Apple Inc. v. WI-LAN Inc., et al

Filing 1

COMPLAINT against WI-LAN Inc. ( Filing fee $ 400, receipt number 0971-8709033.). Filed byApple Inc.. (Attachments: # 1 Exhibit 1, # 2 Exhibit 2, # 3 Exhibit 3, # 4 Exhibit 4, # 5 Exhibit 5, # 6 Civil Cover Sheet)(Scarsi, Mark) (Filed on 6/19/2014)

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Exhibit 5 US008537757B2 (12) United States Patent Arviv et al. (54) (58) ADAPTIVE CALL ADMISSION CONTROL FOR USE IN A WIRELESS COMMUNICATION SYSTEM Field of Classi?cation Search See application ?le for complete search history. (56) References Cited Poway, CA (US); Kenneth L. Stanwood, Cardiff by the Sea, CA (US); David Gazelle, La Jolla, CA (US); Ofer U.S. PATENT DOCUMENTS 3,949,404 A 4/1976 Fletcher et a1. 4,495,619 A Zimmerman, Modiin (IL); Penny l/l985 Acampora Efraim, Kfar Sava (IL); Yair Bourlas, San Diego, CA (US); Sheldon L. Gilbert, San Diego, CA (US) (Continued) FOREIGN PATENT DOCUMENTS 0507384 Bl 0845916 Bl EP (73) Assignee: Wi-Lan, Inc., Ottawa (CA) Notice: (Continued) Jun. 1, 2012 (Under 37 CFR 1.47) (65) Primary Examiner * Kevin C Harper (74) Attorney, Agent, orFirm * Procopio, Cory, Hargreaves Prior Publication Data & Savitch LLP US 2013/0064097 A1 Mar. 14, 2013 (57) Related US. Application Data (60) (60) Continuation of application No. 12/414,363, ?led on Mar. 30, 2009, now Pat. No. 8,213,359, which is a continuation of application No. 11/693,546, ?led on Mar. 29, 2007, now Pat. No. 7,529,204, which is a continuation of application No. 11/350,464, ?led on Feb. 8, 2006, now Pat. No. 7,289,467, which is a division of application No. 10/032,044, ?led on Dec. 21, 2001, now Pat. No. 7,023,798. Provisional application No. 60/258,428, ?led on Dec. 27, 2000. (51) Int- ClH04 W 4/00 (52) OTHER PUBLICATIONS “Asynchronous Transfer Mode (ATM) Technical Overview”, 2nd Edition, Prentice Hall, Oct. 1995, Chapter 3, pp. 21-25. (21) App1.No.: 13/487,013 Filed: l0/l992 6/1998 (Continued) Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. (22) Sep. 17, 2013 None (75) Inventors: Eli Arviv, Modiin (IL); Brian Spinar, (*) US 8,537,757 B2 (10) Patent N0.: (45) Date of Patent: (200901) ABSTRACT The invention relates to communication systems and to sys tems and methods for implementing adaptive call admission control (CAC) in such systems. Adaptive call admission con trol can determine what CPE to base station calls (connec tions) are allowed at any given time. CAC, coupled with precedence, can further determine what connections are sus pended if less bandwidth is available than is currently com mitted. Multiple techniques are disclosed to select connec tions for suspension. These techniques include suspending enough connections through the affected CPE until there is enough bandwidth to meet the remaining commitment, ran domly (or in a round robin fashion) choosing connection to suspend from the entire set of connection, and using prece dence priority levels. US. Cl. USPC ......................................... .. 370/328; 370/465 24 Claims, 6 Drawing Sheets :00 r’ 301, 30:, /306 306 30:1 .106 306 300 l \ A53 TROL mgdc A 1 mm 308 312(1) 1 A Y_,mode C E I046) d: H '14 312(1)) 310 302 /3O6 305 1 {Y \ r 1040») DATA E 104(c) DATA ATA B 4 306 I , 312(9 ‘ 1 F , 4 314(1) , 314(1)) ‘ 304 am“) > > US 8,537,757 B2 Page 2 (56) References Cited U.S. PATENT DOCUMENTS 5,130,983 A 7/1992 Heffner, III 5,297,144 5,420,851 5,444,698 5,471,645 5,511,082 A A A A A 3/1994 5/1995 8/1995 11/1995 4/1996 Gilbert et al. Seshadri et al. Kito Felix How et al. 5,615,212 5,638,371 5,638,374 5,675,573 5,751,708 5,768,254 5,828,695 5,857,147 A A A A A A A A 3/1997 6/1997 6/1997 10/1997 5/1998 6/1998 10/1998 1/1999 RusZcZyk et al. Raychaudhuri et al. Heath Karol et al. Eng et al. Papadopoulos et al. Webb Gardner et al. 5,859,619 A 5,890,055 A 1/1999 Wu et al. 3/1999 Chu et al. 6,006,069 A 12/1999 Langston 6,016,311 6,016,313 6,038,455 6,094,421 6,112,080 6,141,317 6,519,462 1/2000 1/2000 3/2000 7/2000 8/2000 10/2000 2/2003 10/2003 4/2006 5/2006 10/2007 Gilbert et al. Foster, Jr. et al. Gardner et al. Scott Anderson et al. Marchok et al. Lu et al. 5/2008 10/2001 Stanwood et al. .......... .. 370/337 Kato et al. .................. .. 375/222 A A A A A A B1 6,636,500 B2 7,023,798 B2 7,050,407 B1 7,289,467 B2 7,379,441 B2 * 2001/0028678 A1* Krishnamoorthy et al. Bourlas et al. Frazer et al. Bourlas et al. HC Papadopoulos et al., Reduction of Mixed Co-channel Interfer ence in Microcellular STDD Systems, Vehicular Technology Con ference, 1995 IEEE 45th, vol. 2, pp. 759-763. L.H. Charles Lee, “Convolutional Coding, Fundamentals and Appli cations”, Artech House, Inc., 1997, p. 11-51. Lin et al., “Error Control Coding, fundamentals and Applications”, Prentice-Hall Computer Applications in Electrical Engineering Series., 1993, pp. 315-349. Redl et al., “An Introduction to GSM”, Artech House, Inc., 1995; pp. 84, 85 and 95. Sampei et al., “Adaptive Modulation/TDMA Scheme for Personal Multi-Media Communication Systems”, Proceedings of the Global Telecommunications Conference, US, New York, IEEE, Nov. 28, 1994, pp. 989-993. Ue et al., “Symbol Rate and Modulation Level Controlled Adaptive Modulation/TDMN TDD for Personal Communication Systems”, Proceedings of the Vehicular Technology Conference, US. New York, IEEE, vol. Conf. 45, Jul. 25, 1995, pp. 306-310. Ulm et al., “Data-Over-Cable Interface Speci?cations, Radio Fre quency Interface Speci?cation”, Hewlett Packard Interim Speci?ca tion, Doc. Control No. SP-RFII01-970321, published Mar. 21, 1997 by MCNS Holdings, L.P., Section 6, pp. 43-85. Wolf et al., “On the Weight Distribution of Linear Block Codes Formed From Convolutional Codes”, IEEE, IEEE Transactions on Communications, vol. 44:9, Sep. 1996. US. District Court, Northern District of California, “Amended Com plaint for Declaratory Judgment Demand for Jury Trial” ?led Sep. 30, 2008 in Case No. 5:08-cv-4555. J .M. Torrence, L. HanZo, “Upper Bound Performance of Adaptive Modulation in a Slow Rayleigh Fading Channel,” IEEE Electronics Letters, vol. 32, p. 718, Apr. 1996. 2002/0061006 A1 5/2002 Soliman J. Pons and J. Dunlop, “Bit Error Rate Characterisation and Model 2002/0086707 A1* 7/2002 ling for GSM”, IEEE 1998, pp. 3722-3727. P. Bender et al., “CDMA/HDR: A Bandwidth Ef?cient High Speed Wireless Data Service for Nomadic Users”, Communications Maga Zine, IEEE, vol. 38, No. 7, Jul. 2000, pp. 70-77. P. Jain, “On the Impact of Channel and Channel Quality Estimation Struhsaker et al. ......... .. 455/561 FOREIGN PATENT DOCUMENTS EP WO WO WO WO 0891060 9222162 9909779 9953700 0049824 A3 A1 A1 A1 A1 1/1999 12/1992 2/1999 10/1999 8/2000 OTHER PUBLICATIONS C.E Shannon“A Mathematical Theory of Communication”, Bell Sys tem Technical Journal, pp. 379-423 (Part 1), 623-656 (Part II), Jul. 1948. on Adaptive Modulation”, Dec. 2002. J .B. Andersen et al., “Prediction of Future Fading Based on Past Measurements”, Vehicular Technology Conference, VTC 99, vol. 1, pp. 151-155. G. Narlikar et al., “Designing Multihop Wireless Backhand Net works with Delay Guarantees”, Bell Labs, 2005. * cited by examiner US. Patent Sep. 17, 2013 Sheet 1 of6 BSatseion US 8,537,757 B2 US. Patent Sep. 17, 2013 Sheet 2 of6 US 8,537,757 B2 1 m5< 3:: 00m wow 3<5: gm 32m V gm HNMDOE u 25:. > com @om > com .T 4. EN; 3N: g;‘ o; Non 02 02 oom V US. Patent Sep. 17, 2013 =:2m5Eu< 23.:6502 c2o5m2 E238 onc\ e, 21£3I6!258m 23.6052 mom ’, w25SoE53w2Sg.6MS0“2; QEME m m2 k # g /K g2 US 8,537,757 B2 N_ 2u \05 _ /57 858 Sheet 3 of6 Ea: US. Patent Sep. 17, 2013 Sheet 4 of6 US 8,537,757 B2 400 402 Receiver module receives uplink from CPE 4O4\1iRSQ module dclennines signal quality J l 406 RSQ module and control module compare quality of uplink with threshold values 408 ls uplmk using Has quality less robust PHY decreased DO mnde than its across a planned PHY lhreshold? mode? 416 Select and apply more robust PHY mode Select and apply a less robust Has quality PHY mode yes increased across a ‘L Reallocale available bandwidth 4 lhreshol d? 4] , ’ Select second error threshold no * for signal quality? 420 APPIY Precedence FIGURE 4 US. Patent Sep. 17, 2013 US 8,537,757 B2 Sheet 5 0f 6 600 CPE/base station selects more robust PHY mode FIGURE 4 Block 402 I Y Control module determines air link line 602 rate based on a reference PHY mode l V Control module calculates the hard bandwidth 603 commitments based on current PHY mode 606 604 Does the air link line m: hard yes CPE/base station applies more robust PHY mode cornxrurments between the CPE; and base station? A 608 Are air link yes resources available? 610 HO Suspend connection(s) between CPE and base station based on precedence FIGURE 5 US. Patent Sep. 17, 2013 Sheet 6 of6 US 8,537,757 B2 500 502\ Receiver module receives a request for a new connection 504 l V CAC module sums the hard bandwidth commitments between the CPI-Is and base station based on planned PHY modes l 506 510 Control Module determines air link line Allow the new rate based on reference PHY mode connection Y 512 / Control Module determines hard bandwidth 508 commitments based on current PHY mode Does the air link line rate exceed the hard bandwidth commitments? Does the at! link lute rate exceed the hard bandwidth commitments between the CPEs and no base station? Deny the new connection 522 Arc air link resources available? Suspend connection(s) S20 between CPE and base station based on precedence T Allocate air link FIGURE 6 resources to the new connection yes US 8,537,757 B2 1 2 ADAPTIVE CALL ADMISSION CONTROL FOR USE IN A WIRELESS COMMUNICATION SYSTEM premise equipments (CPEs), wherein the base station and the CPEs are each con?gured to increase or decrease the robust ness of their transmission modulation technique by adapting their PHY mode. The system comprises a ?rst CPE having a ?rst modem con?gured to modulate data in a communication link using a ?rst current PHY mode and a ?rst planned PHY mode, a second CPE having a second modem con?gured to RELATED APPLICATIONS This application is a continuation of US. application Ser. No. 12/414,363, ?led Mar. 30, 2009, which is a continuation modulate data in a communication linkusing a second current PHY mode and a second planned PHY mode, and a base ofU.S. application Ser. No. 11/693,546, ?led Mar. 29, 2007, station having a third modem con?gured to transmit and receive data to and from the ?rst and second CPEs. The now US. Pat. No. 7,529,204, which is a continuation ofU.S. application Ser. No. 11/350,464, ?led Feb. 8, 2006, now US. Pat. No. 7,289,467, which is a divisional of US. application Ser. No. 10/032,044, ?led Dec. 21, 2001, now US. Pat. No. 7,023,798, which claims priority to US. provisional patent application Ser. No. 60/258,428, ?led Dec. 27, 2000, all system further comprises a call admission control (CAC) module con?gured to determine whether to allow a new con entitled ADAPTIVE CALL ADMISSION CONTROL FOR USE IN A COMMUNICATION SYSTEM, all of which are nection between the ?rst CPE and the base station or between the second CPE and the base station based on a comparison of a total air link line rate between the ?rst and second CPEs and the base station, wherein the total air link line rate is based on a reference PHY mode, with a bandwidth commitment value incorporated herewith in their entirety by reference. between the base station and the ?rst and second CPEs, wherein the bandwidth commitment is based on the ?rst and BACKGROUND OF THE INVENTION 20 second planned PHY modes. Another aspect is a method for controlling the admission of 1. Field of the Invention The present invention relates to communication systems and to a system and method for implementing adaptive call admission control in such systems. 2. Description of the Related Art A wireless communication system facilitates two-way communication between a plurality of subscriber units (?xed and portable) and a ?xed network infrastructure. Exemplary communication systems include mobile cellular telephone connections in a wireless communication system between a base station and associated CPEs, including a requesting CPE. The method comprises receiving a request for a new 25 connection from a requesting CPE, summing the hard band width commitments between a base station and associated CPEs, including the new connection and existing connec tions, based on a planned PHY mode for each connection, and determining an air link line rate between the base station and 30 the associated CPEs based on a reference PHY mode. The systems, personal communication systems (“PCS”), and method further includes if the air link line rate exceeds the cordless telephones. An objective of these wireless commu hard bandwidth commitments, accepting the new connection nication systems is to provide communication channels on demand between the subscriber units and their respective and determining a second hard bandwidth commitments for the existing connections between the base station and the base stations in order to connect a subscriber unit end user 35 associated CPEs based on a current PHY mode for each with the ?xed network infrastructure (usually a wire-line connection, else denying the new connection. The method still further includes if the air link line rate exceeds the second hard bandwidth commitments, allocating air link resources to the new connection, else determining whether additional air system). In the wireless systems having multiple access schemes, a time “frame” is used as the basic information transmission unit. Each frame is sub-divided into a plurality of time slots. Subscriber units typically communicate with 40 their respective base station using a “duplexing” scheme thus allowing for the exchange of information in both directions of new connection, else suspending at least one of the existing connections between the base station and the associated CPEs. the connection. Transmissions from the base station to the subscriber units are commonly referred to as “downlink” transmissions. Transmissions from the subscriber units to the base station are link resources are available, and if additional air link resources are available, allocating the air link resources to the 45 BRIEF DESCRIPTION OF THE DRAWINGS commonly referred to as “uplink” transmissions. Depending upon the design criteria of a given system, wireless commu FIG. 1 is a simpli?ed block diagram of a wireless commu nication systems have typically used either time division duplexing (“TDD”) or frequency division duplexing nication system including a base station and one or more (“FDD”) methods to facilitate the exchange of information CPEs. FIG. 2 is an illustration of the structure of a Time Division between the base station and the subscriber units. Duplex (“TDD”) frame. 50 SUMMARY OF THE INVENTION 55 The systems and methods have several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope as expressed by the claims which base station and a CPE. FIG. 5 is a ?owchart illustrating the process of precedence being applied to existing connections between the CPE and follow, its more prominent features will now be discussed brie?y. After considering this discussion, and particularly 60 after reading the section entitled “Detailed Description” one will understand how the features of the system and methods provide several advantages over traditional communication the base station. FIG. 6 is a ?owchart illustrating the process of call admis sion control to a new connection between a CPE and the base station. systems. One aspect is a communication system that is con?gured to control the admission of new connections and the suspension of existing connections between a base station and customer FIG. 3 is a block diagram ofa modem. FIG. 4 is a ?owchart illustrating the process of adaptively adjusting a PHY mode for an uplink connection between the DETAILED DESCRIPTION 65 The following detailed description is directed to certain speci?c embodiments of the invention. However, the inven US 8,537,757 B2 3 4 tion can be embodied in a multitude of different systems and limited to a particular transmission sector 106 of the base methods. In this description, reference is made to the draw ings wherein like parts are designated with like numerals station 102. Within a given sector 106, CPEs 104(a), 104(1)), 104(0) receive the same transmission along their respective throughout. downlinks 110(a), 110(1)), 110(0). To distinguish between In connection with the following description many of the data intended for a speci?c CPE, the CPEs can monitor con components of the various systems, some of which are referred to as a “module,” can be implemented as software, ?rmware or a hardware component con?gured to perform one trol information in their respective downlink 110(a), 110(1)), 110(0) and typically retain only the data intended for them. In communication systems that have multiple sectors, the base or more functions or processes. Hardware components can station 102 can include a sectored active antenna array (not include, for example, a Field Programmable Gate Array shown) which is capable of simultaneously transmitting to (FPGA) or Application-Speci?c Integrated Circuit (ASIC). multiple sectors. In one embodiment of the system 100, the active antenna array transmits to four independent sectors. Such components or modules may reside on the addressable storage medium and con?gured to execute on one or more The communication links 112(a), 112(1)), 112(0) are processors. Thus, a module may include, by way of example, components, such as software components, object-oriented software components, class components and task compo referred to as an uplink (i.e., from the CPEs 104 to the base station 102) and can operate on a point-to-point basis. Thus, nents, processes, functions, attributes, procedures, subrou tines, segments of program code, drivers, ?rmware, micro code, circuitry, data, databases, data structures, tables, arrays, uplink 112(a), 112(1)), 112(0). Communication with the base and variables. The functionality provided for in the compo in FIG. 1, each CPE 104(a), 104(1)), 104(0) originates its own 20 station 102 is bi-directional and can be multiplexed on the basis of Time Division Duplexing (TDD). For a TDD trans mission from, for example, CPE 104(a), CPE 104(a) would nents and modules may be combined into fewer components and modules or further separated into additional components send its data along communication link 112(a) to the base and modules.Additionally, the components and modules may station 102 during a preassigned time slot in a transmission advantageously be implemented to execute on one or more frame. The speci?c frame structures of the uplink and down link will be discussed further below. computers. 25 FIG. 1 is a block diagram of an exemplary wireless com munication system 100. Alternatively, the methods and sys Alternatively, the system can employ Frequency Division Duplexing (FDD). In such an FDD system, duplexing of tems herein disclosed can be implemented in wired commu transmissions between the base station and the CPEs is per nication systems (not shown). One exemplary broadband wireless communication system is described in US. Pat. No. formed in the frequency domain. Different sets of frequencies 30 6,016,311, by Gilbert et al., issued Jan. 18, 2000, entitled “Adaptive Time Division Duplexing Method and Apparatus FDD system. for Dynamic Bandwidth Allocation within a Wireless Com munication System,” hereby incorporated by reference. The system 100 includes a base station 102 and at least one cus 35 CPE and the base station. Consequently, each end user con nection can have different and varying usage and bandwidth shows three CPEs 104(a)-(c). More or fewer CPEs can be used. The CPEs and the base station receive and transmit data requirements. Each CPE 104(a)-(c) may service several hun along wireless communication links 110(a)-(c), 112(a)-(c). 40 dred or more end users, but at least one end user will be assigned to transmit and receive data via at least one connec tion through each CPE 104. The data transmitted along the communication links 110, 112 is in analog form, and thus a modem 108 is used to modulate the digital data prior to transmission. FIG. 1 illus trates the modem 108 being located at the base station 102, cate by transmitting their data as radio frequency signals. The term channel refers to a band or range of radio frequencies of suf?cient width for communication. For example, the range of frequencies from 26.500 GHZ to 26.525 GHZ would pro vide a 25 MHZ wide channel. Although the following discus sion uses the example of a system that transmits information within the Local Multi-Point Distribution Services (LMDS) however, a similar or identical modem 108 may be used at the other end of the downlinks 110(a), 110(1)), 110(0) to demodu late the received analog data. Thus, the modems 108 in the 50 base station and each CPE are used for uplinking data from the CPEs to the base station and for downlinking data from the base station to the CPEs. The base station and CPEs can use adaptive modulation and forward error correction (FEC) schemes to communicate. 55 Adaptive modulation, or adaptable modulation density, band at frequencies of approximately 28 GHZ, the invention is not so limited. Information can be transmitted at various frequencies and ranges including, for example, 10 GHZ to 66 GHZ using Quadrature Amplitude Modulation (QAM) sym bols. The systems and methods described herein can also be used in a Multichannel Multi-point Distribution Service includes varying the bit per symbol rate modulation scheme, or modulation robustness, of downlinks and uplinks transmit ted between CPEs and the base station. Examples of such (MMDS) which operates below 10 GHZ. In the MMDS, Orthogonal Frequency Division Multiplexing (OFDM) sym bols may be transmitted between the base station and CPEs as an alternative to single carrier QAM modulation. In such a system, the methods and systems are applied to one or more of the OFDM subchannels. 60 Referring again to FIG. 1, the communication links 110(a), 110(1)), 110(0) are referred to as downlinks (i.e., from the base station 102 to the CPE’ s 104) and can operate on a point (base station)-to-multi-point (CPE’s) basis. Transmissions to and from the base station 1 02 can be directional in nature, and thus Each CPE 104 is further coupled to a plurality of end users that may include both residential and business customers. Each customer can have one or more connections between the tomer premise equipment. The system depicted in FIG. 1 FIG. 1 does not show buildings or other physical obstruc tions (such as trees or hills, for example), that may cause channel interference between data from communication links 110, 112. The CPEs 104 and the base station 102 communi are allocated for uplink and downlink transmissions. The systems and methods described herein can be used in such an modulation schemes include quadrature amplitude modula tion-4 (QAM-4), QAM-16, QAM-64, and QAM-256. If QAM-4 is used, each resulting symbol represents two bits. If QAM-64 is used, each resulting symbol represents six bits. Adaptive FEC includes varying the amount of error correc tion data that is transmitted in the downlink and/ or uplink. 65 Channel characteristics, for example the modulation and FEC, for the downlink and/or uplink can be varied indepen dently. For ease of explanation, the phrase “PHY mode” is US 8,537,757 B2 5 6 used to indicate characteristics of a communication channel or link, including for example, modulation scheme and/ or an FEC. 308 includes information for the CPEs to synchronize With The PHY mode(s) planned for use in the sector 106 is normally determined as a function of the geographical rela the base station 102. The frame control header 308 can include control information indicating Where a PHY mode change occurs in the doWnlink. The frame control header 308 can also include a map of a subsequent uplink subframe 304. tionship betWeen the base station 102 and the CPEs, the rain region, and the implementation or modern complexity of the This map allocates the PSs 306 in the uplink subframe 304 betWeen the different CPEs. The frame control header 308 CPEs. Examples of rain regions include rain regions A-Q. can further include a map of attributes of the doWnlink data Recommendations for modeling the rain region’s effect on signal propagation can be found in Rec. ITU-R PN.837.1. Thus, a planned PHY mode may be different for the CPEs depending on the capabilities and transmission quality of each CPE 104 and base station 102 pair. For ease of explana tion, the phrase “planned PHY mode” is used to indicate the planned PHY mode for a CPE 104 and base station 102 pair 310. For example, attributes may include, but are not limited to, the locations of the PSs 306 in the subframe 302 that are intended for each individual CPE. The doWnlink data 310 is transmitted using a pre-de?ned PHY mode or a sequence of PHY modes With three PHY modes A, B, and C depicted in FIG. 2 as an example. Indi vidual or groups of PSs 306 in the doWnlink subframe 302 are as described above. assigned to data intended for speci?c CPEs 104. For example, Better environmental conditions, e. g., less distance, betWeen some CPEs (such as CPE 104(0) for example) and the base station 102 may permit the use of a less robust PHY mode by such CPEs as compared to a PHY mode used by CPEs located farther from the base station. For example, if the base station 102 could assign PSs in one, some, or all of 20 CPE 104(0) is capable of receiving QAM-64 data coupled With achieving adequate transmission quality betWeen CPE 104(0) and the base station 102, all data transmitted betWeen the CPE and the base station can be modulated using QAM 64. In the same system CPEs 104(a), 104(b), Which, for 25 Still referring to FIG. 2, the uplink subframe 304 comprises uplink data 314(a)-(n). The uplink subframe 304 is used by example, are only capable of receiving QAM-4 data, Will only transmit and receive QAM-4 data. By using different or vari able PHY modes for different CPEs associated With a single base station, the communication system 100 as a Whole increases its bandWidth utilization. 30 The transmission quality betWeen the base station 102 and a CPE 104 may not only vary betWeen each CPE and base station pair as described above, but may also vary over time, or betWeen the uplink and doWnlink transmissions of a single 35 pair (i.e. asymmetrical transmissions). For example, in FIG. 1, the transmission quality may signi?cantly decrease during a rain or snoW storm. When the link quality is decreased, there the CPEs 104(a)-(0) to transmit information to the base sta tion 102. The subframe 304 is subdivided into a plurality of PSs 306. Each CPE 104(a)-(0) transmits its information dur ing its allocated PS 306 or range of PSs 306. The PSs 306 allocated for each CPE can be grouped into a contiguous block ofa plurality of data blocks 314(a)-(n). The CPEs use data blocks 314(a)-(n) to transmit the uplink subframe 304. The range of PSs 306 allocated to each block in the plurality of data blocks 314(a)-(n) can be selected by the base station 102. The data transmitted in each data block 314(a)-(n) is modulated by the transmitting CPE. For example, CPE 104 (a) modulates and transmits uplink data block 314(a). The is an increased chance that transmitted data along communi cation links 110(a), 110(1)), 110(0), 112(0), 112(1)), 112(0) the PHY modes A, B, and C for transmitting data to CPE 104(a). In FIG. 2, the data is divided into three PHY modes, Where PHY mode A (312(a)) is the most robust modulation (i.e. least prone to transmission errors caused by signal inter ference) and While PHY mode C (312(0)) is the least robust (i.e. most prone to transmission errors caused by signal inter ference). In betWeen these PHY modes is PHY mode B (312 (19)). Additional PHY modes can also be used. 40 same or different PHY modes can be used for each data block may be unrecognizable or lost to the receiving base station or 314(a)-(n). The data blocks 314(a)-(n) can also be grouped by CPE. To accommodate these time variations in link quality, the communication system 100 can dynamically adjust or “adapt” the PHY mode for each base station 102 and CPE 104. In such an adaptive system, the bandWidth utilization of the communication system 100 further increases. FIG. 2 represents a time division duplexing (“TDD”) frame and multi-frame structure for use in communication system PHY mode. During its data block, the CPE transmits With a PHY mode that is selected based on measured channel parameters from 45 measured channel parameters from its prior transmission(s). The process for selecting a PHY mode Will be explained in more detail beloW. The measured channel parameters can be 100. Frame 300 includes a doWnlink subframe 302 and an uplink subframe 304. The doWnlink subframe 302 is used by its prior transmission(s). Similarly, the base station can select a doWnlink PHY mode for a communication link based on 50 the base station 102 to transmit information to the CPEs included in the uplink subframe 304 for transmission by the CPEs to the base station or can be included in the doWnlink 104(a)-(0). In any given doWnlink subframe 302, all, some, or subframe 302 for transmission by the base station to the CPE. none of the transmitted information is intended for a speci?c CPE 104. The base station 102 may transmit the doWnlink Once received, the base station or CPE can utilize the channel parameters to determine if the PHY mode of the doWnlink subframe 302 prior to receiving the uplink subframe 304. The uplink subframe 304 is used by the CPEs 104(a)-(0) to trans 55 Each CPE 104 can receive all doWnlink transmissions that are modulated using its current PHY mode or are modulated using a more robust PHY mode than its current PHY mode. mit information to the base station 102. Subframes 302, 304 are subdivided into a plurality of physical layer slots (PS) 306. Each PS 306 correlates With a duration of time. In FIG. 2, each subframe 302, 304 can be subframe 302 or the uplink subframe 304 should be changed. The frame control header 308 is typically modulated using one-half millisecond in duration and include 400 PS for a total the most robust PHY mode to ensure that all CPEs 104(a)-(0) may receive it. Because each CPE receives the frame control of 800 PS per frame 300. Alternatively, subframes having header, each CPE 104 is initially synchronized With the longer or shorter durations and With more or feWer PSs can be doWnlink subframe 302 at the beginning of the frame 300. The doWnlink subframe can be sorted by robustness, Which alloWs each CPE to maintain synchronization during the sub sequent portion of the doWnlink that could include data for that CPE. 60 used. Additionally, the size of the subframes can be asym metrical and can be varied over time. 65 Each doWnlink subframe 302 can include a frame control header 308 and doWnlink data 310. The frame control header US 8,537,757 B2 7 8 FIG. 3 is a block diagram ofa modem 108 Which can be used to modulate/demodulate data in the Wireless communi cation system 100 described above. The modem 108 is used to control the number and quality of existing and neW connec tions betWeen the CPEs and base station. Modems 108 are used by the base station 102 and CPEs 104 to modulate and demodulate data. For ease of description, the modem 108 Will noW be described With reference to the base station 102. The modem 108 can include a control section 108(a) and a a communication system that adapts PHY modes, the selec tion of a PHY mode can be based on channel parameters monitored/measured by the RSQ module 208. These channel parameters can include the signal to noise ratio (SNR) of the modulated data at the receiver module 202 at the base station 102. A bit error rate (BER), at the base station 102 or CPE 104, can also be used in selecting the PHY mode. For example, When the received signal drops beloW a threshold value for a SNR, a more robust PHY mode can be selected by the modem 108 for the connection. Signal quality can be measured over a period of time by the RSQ module 208, and, in response to changes in the signal quality, the control mod ule 212 determines if the PHY mode for the transmitting CPE should be changed. The control module 212 at the base station 102 interfaces With the transmitter module 204 to control the PHY mode for the modem 108. Further, the control module 212, via the transmitter module 204, can alert the transmitting CPE to change its PHY mode. Measuring signal quality over time helps avoid cyclic changes in the PHY mode due to modem section 108(b). The modem section 108(b) includes a receiver module 202 and a transmitter module 204. The con trol section 108(a) includes a call admission control (CAC) module 206, a Receive Signal Quality (RSQ) module 208, a precedence module 210, and a control module 212. Alterna tively, the functionality provided for by the control section 108(a) can be separate from the modem 108. Further, the control section 108(a) components and modules may be com bined into feWer components and modules or further sepa rated into additional components and modules Within the base station 102 and/or CPE 104. At a base station 102, the transmitter module 204 converts digital data to an appropriately modulated analog signal com municated as a doWnlink 110, using for example, QAM modulation and FEC. The analog signal may also be up con verted to a carrier frequency prior to transmission. The 20 25 receiver module 202 at the base station 102 demodulates an uplink 112(a), 112(1)), 112(0) and converts it back to digital form. When con?gured as a CPE 104(a), the transmitter module 204 converts digital data to an appropriately modu lated analog signal communicated as an uplink 112, using for example, QAM modulation and FEC. The analog signal may 30 sion. The receiver module 202 at the CPE 104 demodulates a quality of service requested by the end users served by the 35 end users are variable and selectable. The amount of band on intrinsic factors relating to the neW connection as Well as communication system level factors. Examples of intrinsic 40 include the type and quality of service for the existing con nections, Whether available bandWidth is allocated to the 45 50 information rate and the quality of service required by that service (and also taking into account bandWidth availability and other system parameters as Will be described beloW). For bandWidth allocation for each doWnlink subframe 302 and uplink subframe 304 in a frame 300 (see FIG. 2). In contrast, certain types of data services such as Internet Protocol data services (“TCP/IP”) are bursty, often idle (Which at any one instant may require Zero bandWidth), and are relatively insen sitive to delay variations When active. 55 ured to monitor signal quality of the received uplink signal. In requesting CPE, the available bandWidth in the communica tion link, and the portion of the frame that is allocated for the uplink and doWnlink. An example of a type and quality of service that can be evaluated by the CAC module 206 are hard bandWidth commitments. The CAC module 206 can be con?gured to determine Whether there Will be enough bandWidth to support all of the connections betWeen the CPEs 104 and the base station 102. For example, the CAC module 206 can determine Whether there Will be enough bandWidth for hard bandWidth commit ments betWeen the base station and CPEs. These hard band Width commitments can include, for example, constant bit rate (CBR) connections, the minimum cell rate (MCR) por tion of a guaranteed frame rate (GFR) connections, and some function of sustainable cell rate (SCR) for variable bit rate 60 (VBR) and variable bit rate real-time (VBR-rt) connections. Alternatively, hard bandWidth commitments could be the bandWidth measured, rather than calculated, that is necessary to provide the quality of service (QoS) desired for the con nection. For ease of explanation, the folloWing description 65 uses hard bandWidth commitments as an exemplary type of Referring again to FIG. 3, the Receive Signal Quality (RSQ) module 208 interfaces With the receiver module 202 and the control module 212. The RSQ module 208 is con?g factors are a quality of service and a type of service requested by the end user for the neW connection. The extrinsic factors are external to the neW connection. The extrinsic factors can Width dedicated to a given service can be determined by the example, Tl -type continuous data services typically require a great deal of bandWidth having Well controlled delivery latency. Until terminated, these services require constant What CPE to base station connections are alloWed at any given time. For example, the receiver module 202 can receive a request for a neW connection betWeen the CPE and base station in the uplink 112. The CAC module determines Whether to grant that request. This determination can be based CPE. A CPE or base station can continue an existing connec tion or alloW a neW connection depending on, for example, a user’ s de?ned quality of service, bandWidth needs, and trans mission quality. Thus, each end user potentially uses a differ ent broadband service having different bandWidth and latency requirements. Moreover, each user can select a portion(s) of their bandWidth to have variable priority levels, or prece dence. To this end, the type and quality of service available to the The RSQ module at the CPE can measure signal quality for a signal that is transmitted by the base station 102 and received by the CPE. The CPE can alert the base station to change the base station’s transmitting PHY mode. In one embodiment, only the modem 108 at the base station 102 includes the control module 212. In this embodiment, each CPE measures its oWn signal quality and transmits its value Within its uplink 112 to the base station 102. The control module 212 is then able to monitor the signal quality of the signal received by the CPEs to determine if the doWnlink 110 PHY modes should be changed. The call admission control (CAC) module 206 determines also be up converted to a carrier frequency prior to transmis doWnlink 110 and converts it back to digital form. The Wireless communication system 100 can provide “bandWidth-on-demand” to the CPEs. Thus, the uplink can include bandWidth requests for neW and existing connections from end users. The CPEs request bandWidth allocations from their respective base station 102 based upon the type and transient changes in the communication link’s quality. connection. HoWever, the systems and methods disclosed herein are not so limited and can be applied to any type of US 8,537,757 B2 10 connection. Further, the systems and methods can be applied freed up bandWidth When the decision to alloW neW connec to one or more types of connections. tions is based upon the minimum air link line rate. In another embodiment of the communication system 100 The CAC module 206 determines Whether there is enough that adapts PHY modes, the CAC module 206 alloWs the CPE to take advantage of the freed up bandWidth. The CAC mod bandwidth to allow the neW connection. This can be deter mined by summing the hard bandWidth commitments for each connection on each CPE 104(a), 104(1)), 104(0) (see ule 206 limits neW connections based on a comparison of the bandWidth required for the connection if it is modulated using the CPE’s planned PHY mode With the available bandWidth. The available bandWidth is determined by summing the CPE’s hard bandWidth commitments that Would be used by FIG. 1). Thus, each CPE Will have a hard bandWidth commit ment for its existing connections. All of the hard bandWidth commitments from the CPEs can then be summed to get the total hard bandWidth commitments for all of the existing connections through base station 102. The control module 212 can perform these calculations. The CAC module 206 the existing connections if those connections Were modulated using the planned PHY mode of the CPE. If the available bandWidth is equal to or exceeds the bandWidth required for compares the total hard bandWidth commitments to an air link line rate. The air link line rate is the amount of bandWidth the neW connection, the CAC module 206 Will alloW the connection. HoWever, if the CPE operates using a less robust available betWeen the CPEs and base station. If the air link line rate exceeds the total hard bandWidth commitments, the neW connection is alloWed. If the total hard bandWidth com mitments meet or exceed the air link line rate, the CAC module 206 denies the neW connection. In the communication system described above, each con nection betWeen the CPE 104 and base station 102 Will have 20 PHY mode than its preferred PHY mode, there is the potential that data through the CPE Will be lost. In the presence of adaptive PHY modes and to take advan tage of the CPE’s planned PHY mode, the bit rate associated With each connection’ s PHY mode is compared. Connections at different PHY modes (modulation and FEC) effectively have different bit rates, or air link line rates, and thus are not a planned PHY mode. The planned PHY mode is used by the directly compared. One method for comparing these bit rates CAC module 206 in determining Whether to alloW the neW is to normaliZe the PHY modes associated With each connec connection. As Will be explained beloW, the calculation of the total hard bandWidth commitments for any given sector 106 25 (see FIG. 1) presents additional dif?culties for communica tion systems 100 Which adapt PHY modes. tion. Equation 1, beloW, can be used to normalize the bandWidth used for connections through an individual CPE. In communication systems 100 that adapt, or vary, their PHY modes, the available bandWidth necessary for existing 30 (a)-(c), 112(a)-(c) is adaptive, the robustness of each com munication link can vary (see FIG. 1). As the robustness varies, the bandWidth allocated for an existing connection or Where WCPEZ- is a normaliZed value or Weight for the entire 35 40 45 to the equivalent bandWidth of its connections and the current modulation associated With each connection. Er is the number of bits per unit time that are transmitted by the CPE for a connection. Each connection is modulated using an associ ated PHY mode. The term mod is the inverse of the associated PHY mode ef?ciency that is used to modulate the connection. betWeen CPE 104(a) and the base station 102, 10,000 bits/ s Were transmitted using QAM-4, and during a second connec tion betWeen CPE 104(a) and the base station, 18,000 bits/ s Were transmitted using QAM-64, Equation 1 Would be: WCPEIO4(Q)I(IO,OOO bits/s*1/2 symbol/bit)+(l8,000 50 cient PHY mode regardless of Whether the least e?icient PHY mode is actually used. The least ef?cient PHY mode can bits/s*1/6 symbol/bit):8,000 bits/s. The 8,000 bits/s for CPE 104(a) is then added to WCPE104 include, for example, QAM-4 modulation With a maximum amount of FEC overhead bits. This method ensures that dur ing adverse Weather conditions each CPE Will be able to select its least e?icient PHY mode and transmit its data Within bandWidth used by an individual CPE. WCPEZ. is proportional The bit/symbol rate for QAM-64 is 6, for QAM-l6 is 4, and for QAM-4 is 2. For example, if during a ?rst connection Would be required if all of the existing connections betWeen the CPEs and base station Were modulated using a least e?i Equation 1 [:1 neW connection Will also vary. In such communication systems, connections are alloWed to be modulated With PHY modes that are more or less robust than the planned PHY mode. Each end user connection can dynamically select its current PHY mode. This current PHY mode can be different than the planned PHY mode that Was planned for the connection. If a connection is modulated using a more robust PHY mode than the planned PHY mode, the connection Will exceed its allocated bandWidth. In an embodiment of a communication system 100 that adapts PHY modes, the CAC module 206 alloWs neW con nections With reference to a minimum air link line rate. The minimum air link line rate is a measure of bandWidth that " WCPE; = 2 ER * mod connections can vary. Since each PHY mode used by the base station 102 and/or CPE 104 for its communication link 110 55 (b) and WCPEIO4(C) to determine a total normaliZed bandWidth for the CPEs in sector 106. Normalization is used to determine the effective hard band Width commitment usage through the modem 108. The CAC module 206 interfaces With the control module 212 to com its assigned bandWidth Without losing its connection With the pare the different PHY modes for the existing connections base station. In this embodiment, the CAC module 206 Will and the neW connection With the available bandWidth betWeen the base station 102 and CPEs 104. In this embodi ment, the control module 212 is con?gured to normaliZe each CPE’s air link line rate. Once the control module 212 has determined the normaliZed value for each CPE’s committed bandWidth requirements, the CAC module 206 can sum and deny a neW connection if the neW connection Will cause the CPE to exceed its minimum air link line rate. The CAC 60 module 206 can determine Whether to alloW or deny a neW connection in conjunction With the control module 212. Dur ing spells of good Weather, the CPE can select a less robust PHY mode for its current PHY mode. By selecting a less robust PHY mode, additional bandWidth betWeen the CPE and base station Would be freed up. HoWever, the communi cation system 100 is constrained from taking advantage of the compare them against a common air link line rate. 65 Equation 2, beloW, can be used by the CAC module 206 to determine the total bandWidth used, i.e. WLMFW, by all of the CPEs in the sector. US 8,537,757 B2 11 12 able. Should additional bandwidth be needed when only a few " existing connections, between the base station 102 and CPEs Equation 2 WLink = z WCPEi 104 in sector 106, select a more robust PHY mode, the base station 102 may be able to reallocate the available bandwidth. [:1 Thus, if the communication system is suf?ciently under sub scribed, the CPE 104 can use the additional air link resources Where WCPEZ- is a normalized value or weight for the entire bandwidth used by an individual CPE in the sector. it requires when using a more robust PHY mode than its planned PHY mode during the 53 minutes. If many existing For example, with PHY modes of QAM-4, QAM-16, and QAM-64, each using the same FEC, QAM-4 requires 3 times connections between the base station and CPEs are subject to similar adverse environmental conditions, the base station the air link resources, or bandwidth, of QAM-64 and QAM 16 requires 1.5 times the air link resources of QAM-64. In this example, the control module 212 can normalize to QAM-64. Thus, CPEs operating at QAM-64 would have their hard bandwidth commitments multiplied by a weight of 1, CPE’s operating at QAM-16 would have their hard bandwidth com 102 may be unable to accommodate the CPEs’ bandwidth requests. When the air link resources aren’t available, the precedence module 210 selects which of the existing connec tions from the CPEs 104 (a)-(c) to suspend. The precedence module 210 interfaces with the control module 212 to compare the bit rates for the existing connec tions through each CPE based on each CPE’s current PHY mode. While the CAC module 206 compares the planned mitments multiplied by a weight of 1.5, and CPE’s operating at QAM-4 would have their hard bandwidth commitments multiplied by a weight of 3. The CAC module 206 then sums these hard bandwidth commitments and compares the total against a line rate of a communication link operating entirely at the selected normalized PHY mode, QAM-64 with the single FEC. Alternatively, the control module 212 normalizes to QAM-4 by applying weights of 1/3 to QAM-64, 1/2 to QAM-16, and 1 to QAM-4. The selection of QAM-64 and PHY modes of the CPEs to determine whether a new connec 20 current PHY modes to the selected reference air link line rate to determine if a suspension should occur. The control mod ule 212 is con?gured to compare the current PHY modes of 25 QAM-4, each with a single FEC, for use as a normalization PHY mode are only examples. Any PHY mode could be used to de?ne the air link line rate for normalizing the connections between the CPEs and base station. Still referring to FIG. 3, the precedence module 210 will 30 apply a priority, or precedence, to one or more connections tional bandwidth until there is enough bandwidth to meet the when less bandwidth is available than required to meet the 35 connections based on planned PHY modes of the CPEs but ever, before connections are suspended, the base station 102 can re-allocate bandwidth, that is not intended for hard band width commitments, among the CPEs to increase the avail able bandwidth for hard bandwidth commitments. Alterna tively or in addition to, in TDD systems, the base station 102 can adjust the portion of a downlink subframe 302 and of an 40 45 bandwidth connections with the base station 102 suspended. These CPEs may receive the full brunt of the planned 53 minutes per year outage. In contrast, other CPEs (in particu lar, those barely unable to meet the availability number at the next less robust PHY mode) would have plenty of bandwidth 50 because connections through the geographically challenged 55 CPE’s would be suspended before they need to drop to a more robust PHY mode and request additional bandwidth. Alternatively, the precedence module 210 can also ran domly select connections for suspension or select them in a round robin fashion. The precedence module 210 chooses connection to suspend from the entire set of connections that have hard bandwidth commitments through the CPEs in the sector 106. The CPEs subject to potential suspension include CPEs that may still be operating at their planned PHY mode. uplink subframe 304 in the frame 300 (see FIG. 2) to increase not available, the precedence module 210 selects which con nections from among the CPEs are suspended. Bandwidth problems can arise when one or more CPEs are using more robust PHY modes than their planned PHY modes for their connections. For example, if communication system 100 was designed for 99.99% availability, a comparison would be made between a CPE’s geographical proximity to the base station and the communication system’s rain region. Based on this comparison, a planned PHY mode is selected for that CPE that allows it to operate at that planned PHY 60 ability numbers since the planned outage is evenly shared. For mode than its planned PHY mode, it will require additional during this 53 minutes depending on whether additional air link resources in the communication system 100 are avail In this embodiment, the communication system 100 as a whole, and each individual connection still meets its avail mode or a less robust PHY mode the entire year except for approximately 53 minutes. If a CPE exceeds a SNR or BER threshold and transmits its uplink using a more robust PHY bandwidth for these 53 minutes. At least two things can occur likely be subject to the application of precedence. In this embodiment, CPE’s are penalized by their geographic prox imity to the base station 102. For example, the same CPEs, those that are barely able to meet their availability numbers at their planned PHY modes, would be the ?rst to have their hard the available bandwidth for a CPE that requires additional bandwidth due to a change in the current PHY mode or the addition of a connection. However, if additional bandwidth is remaining demand. The amount of outage during the year for the connections through the affected CPE 104 is planned based on the availability and rain region as discussed above. CPEs 104 located at greater distances from the base station 102 or having limited visibility of the base station wouldmore some or all of the CPEs are operating at a more robust (less e?icient) current PHY mode. The precedence module 210 determines which connection(s) are to be suspended. How the CPEs. As explained above, one method for comparing the PHY modes is normalization. Once normalized, the prece dence module 210 determines if additional bandwidth between the CPEs and base station is available. If additional bandwidth is available, the precedence module 210 can deter mine a margin value. If additional bandwidth is not available, the precedence module 210 selects which connections are going to be suspended. The precedence module 210 can be con?gured to suspend enough connections through the CPE that is requesting addi now be described. The precedence module 210 interfaces with the receiver module 202 and the control module 212 to hard bandwidth commitments. This can occur when the CAC module 206 is con?gured as described above to limit new tion is allowed, the precedence module 210 compares the 65 example, if a rain fade caused the base station 102 and CPEs to lose half of their bandwidth, each connection from among all of the CPEs would, on average, see only 26 minutes outage per year rather than 53 minutes. Thus, the precedence aspect of adaptive CAC can allow you to increase system availability US 8,537,757 B2 13 14 (26 minutes outage vs 53 minutes outage) or capacity. For etc.) and the ability of both the transmitting and receiving example, operating a CPE 104 at a less robust PHY mode than components (eg CPE 104 and base station 102) to respec Would typically be planned for the CPE increases the sys tively transmit and receive data. The base station 102 can tem’ s capacity. The communication system can rely on adap determine the quality of each uplink 112(a)-(c). Alternatively, tive CAC coupled With precedence to distribute the outage among all of the CPEs. This achieves the planned 53 minutes outage, but With increased modulation ef?ciency for the CPE operating at the less robust PHY mode. the base station 102 periodically transmits channel parameter measurements, Which are indicative of the quality of a CPE’ s uplink 112, to that CPE 104. The CPE 104 then uses these channel parameter measurements to determine the quality of its uplink. These channel parameter measurements can include a SNR and/or a BER measurement of the uplink 112(a)-(c). For example, base station 102 can determine the Further, the precedence module 210 can use levels in con junction With the random selection method discussed above When selecting Which connections to suspend. In this embodi ment, each connection betWeen the CPEs 104(a)-(c) and base station 102 is assigned a precedence level. Alternatively, each CPE is assigned a precedence level for its connections. For example, there are ?ve levels, one through ?ve, With prece dence level one being assigned to the most important connec tions and precedence level ?ve being assigned to the least important connections. The random selection of connections for suspension is applied as discussed above With reference to the second embodiment. HoWever, instead of applying the quality of uplink 112(c) based on a measurement by its RSQ module 208 (see FIG. 3). A single SNR measurement or a series of several SNR measurements taken during a frame 3 00 (see FIG. 2) or during multiple frames may be used to deter mine the uplink quality. The control module 212 can analyZe multiple measurements to determine an uplink’s quality. Continuing to block 406, the base station 102 or CPE 104 compares the calculated uplink quality With a current PHY 20 method of the second embodiment to all connections simul taneously, the precedence module 210 applies it based on PHY mode is changed. For example, if CPE 104(a) is cur rently uplinking data to base station 102 using PHY mode B, the PHY mode Will change When the uplink quality exceeds each connection’s assigned precedence level. Continuing With the example above, the random selection Would be ini tially applied to connections assigned to precedence level 25 an upper threshold or goes beloW a loWer threshold. ?ve. If and When the precedence level ?ve connections are Next at decision block 408, the CPE determines Whether the uplink quality has decreased and crossed a PHY mode loWer threshold according to the comparison made in block exhausted, the precedence module 210 applies the random selection process to connections assigned to precedence level 406. Continuing With the example above, if the PHY mode four and so on until there is adequate bandWidth available for the remaining connections that have hard bandWidth commit 30 other connections. Further, the precedence module 210 can alloW connections 35 second threshold is implemented to maintain the connection at the same PHY mode. HoWever, the error rate associated With the connection may increase. FIG. 4 is a ?owchart illustrating the process of adaptively adjusting a PHY mode for a connection betWeen the base station 102 and a CPE. This process can be implemented by a modem 108 at a base station. Alternatively, this process is performed by a modem 108 at the CPE. A speci?c CPE 104 can change its uplink PHY mode independent of that CPE’s loWer threshold associated With PHY mode B has not been crossed, ?oW proceeds to decision block 410 Where the sys tem determines Whether the uplink quality has crossed an ments. Thus, individual connections can be selected to have their uplink or doWnlink transmissions suspended in favor of to continue to operate With their current PHY mode even When a ?rst SNR or BER threshold is exceeded. Instead, a mode threshold. The current PHY mode threshold can include an upper threshold and a loWer threshold at Which the upper PHY mode threshold associated With PHY mode B. If the current modulation upper threshold has been exceeded, ?oW continues to block 412 Where the PHY mode is changed to a less robust, denser modulation. For example, PHY mode C is selected for CPE 104(a). The base station 102 can send a request to the CPE 104 indicating a desired uplink PHY mode change. Alternatively, the base station 102 transmits an uplink 40 map to all CPEs 104 in the doWnlink subframe 302 (see FIG. 2) indicating Which CPEs have been allotted uplink PS’ s and the PS’s associated PHY modes. The base station 102 indi cates to an individual CPE 104 that the PHY mode has been changed by allotting uplink subframe 304 PSs to that CPE doWnlink PHY mode. The speci?c CPE’s PHY mode can also that use a less robust PHY mode. For example, if the uplink PHY mode for CPE 104(a) is to be changed from PHY mode be independent of the uplink PHY modes used by other CPEs B to PHY mode C, the base station 102 assigns uplink sub 104 Within the same sector 106. Because the base station 102 frame PS’s Which are to be modulated using PHY mode C. This uplink assignment serves as an indicator to the CPE that must synchronize With each individual CPE 104 that uplinks data, the uplink quality may be different than the doWnlink 45 50 quality With a speci?c CPE 104. The base station 102 can perform the process of adaptively adjusting the uplink PHY mode used by a speci?c CPE 104. As such, a similar process may be completed for each CPE 104 Within the sector 106 in order to adaptively adjust each CPEs 104 uplink modulation. The folloWing description describes a process for adap 55 tively adjusting a PHY mode for an uplink from a CPE to a base station. The same process is used for adaptively adjust ing a PHY mode for a doWnlink from the base station to the CPE. In particular, ?oW begins in start block 400. How moves to its uplink PHY mode has been change. FloW continues to a block 413 Where the system can reallocate the neWly available bandWidth. For example, the neWly available bandWidth can be allocated for neW or existing hard bandWidth commit ments, neW connections, or connections that had been previ ously suspended. How then returns to block 402 as described above. Returning to decision block 410, if the current PHY mode upper threshold has not been exceeded, ?oW continues to block 402 as described above. 60 Returning to decision block 408, if the PHY mode loWer threshold has been crossed, ?oW proceeds to a decision block 414 Where the system determines Whether the connections, betWeen the CPE and base station that have a hard bandWidth commitment, are using a less robust PHY mode than the 65 module 208. The quality may be a function of the state of the planned PHY mode for the connections. If the connection(s) is using a less robust PHY mode than its planned PHY mode, transmission medium (e.g. air, foggy air, Wet air, smoky air, the process proceeds to block 416 Where a more robust PHY a block 402 Where a receiver module 202 at a base station 102 receives an uplink from a CPE 104. How proceeds to block 404, Where the quality of the channel parameters for the uplink 112 is determined by a receive signal quality (RSQ) US 8,537,757 B2 15 16 mode is selected for the connection(s). If the base station determines Whether the uplink quality has crossed a thresh bandWidth in the doWnlink subframe 304 (see FIG. 2). If 104 in the doWnlink subframe 302 indicating Which CPEs have been allotted uplink PS’s along With the PS’ s associated additional air link resources are available, How proceeds to block 606 Where the more robust PHY mode is applied for the existing connection. How then returns to block 402 of FIG. 4 Where the base station 102 receives the next uplink from a CPE 104. Returning to decision block 608, if additional air link PHY modes. This alloWs the base station 102 to indicate to an resources are not available, How moves to a block 610 Where individual CPE 104 that the PHY mode has been changed by the precedence module 210 suspends existing connections allotting uplink subframe 304 PSs to that CPE that uses a more robust PHY mode. For example, if the uplink PHY mode for CPE 104(a) is to be changed from PHY mode B to betWeen the base station 102 and the CPEs 104. As described PHY mode A, the base station 102 assigns uplink subframe CPE, randomly suspend connections betWeen the base station old, the base station 102 can send a request to the CPE 104 indicating a desired uplink PHY mode change. Alternatively, the base station 102 can transmit an uplink map to all CPEs PS’s Which are to be modulated using PHY mode A. This uplink assignment serves as an indicator to CPE 104(a) that above, the precedence module 210 can, for example, suspend connections only betWeen the base station and the affected 5 its uplink PHY mode has been change. How then continues to block 420 Where a precedence module 210 (see FIG. 3) deter mines Whether connections betWeen the base station and the CPEs are to be suspended. Precedence Will be explained With reference to FIG. 5. How then continues to block 402 as and all of the CPEs in a sector 106, or suspend connections betWeen the base station and all of the CPEs in the sector in a round-robin fashion. Further, the precedence module 210 can randomly suspend connections betWeen the base station and 20 described above. Returning to decision block 414, if the connection’s cur rent PHY mode is at least as robust as its planned PHY mode, the process continues to decision block 418 Where the control module 212 can replace the loWer threshold associated With the current PHY mode of the connection that has the hard bandWidth commitment With a second loWer threshold. The process continues to block 402 as described above except that at block 406 the RSQ module 208 and the control module 212 25 use the second loWer threshold to compare With the measured 30 the CPEs that have a loWer precedence priority than other connections. Alternatively, the precedence module 210 can suspend the connections that have a loWer precedence priority in a round-robin fashion. The process moves to block 606 as described above Where the more robust PHY mode is applied for the existing connection. The process then returns to block 402 of FIG. 4 Where the base station 102 receives the next uplink from a CPE 104. FIG. 6 is a ?owchart illustrating the process of call admis sion control for a neW connection betWeen a CPE and the base station. This process can be implemented at a base station. Alternatively, this process is performed at the CPE. FloW begins in start block 500. How proceeds to block 502 Where signal quality of the connection. Returning to decision block 418, if the control module does the base station receiver module receives a request for a neW not select the second loWer threshold, the process moves to a CAC module 206 sums the hard bandWidth commitments betWeen the CPEs and base station based on the planned modulations of the CPEs. Next, at a block 506, the control module 212 determines an air link line rate for the existing connections betWeen the base station and CPEs based on the reference PHY mode. FloW moves to a decision block 508 Where the CAC module 206 determines Whether the air link line rate determined at block 506 exceeds the hard bandWidth commitments determined at block 504. If the air link line rate exceeds the hard bandWidth commitments, the process con tinues to a block 510 Where the CAC module 206 alloWs the neW connection. HoWever, air link resources are not initially allocated to the connection since the connection has been alloWed based on the planned PHY modes of the CPEs and block 420, as described above, Where the precedence module 21 0 (see FIG. 3) determines Whether connections betWeen the connection. The process continues to block 504 Where the 35 base station and the CPEs are to be suspended. Precedence Will be explained With reference to FIG. 5. Once precedence has been applied, the process returns to state 402 as described above. FIG. 5 is a ?oWchart illustrating the process of applying precedence to existing connections betWeen the CPEs 104 and the base station that have hard bandWidth commitments. 40 This process can be implemented by a modem 108 at a base station. Alternatively, this process is performed by a modem 108 at the CPE. FloW begins in start block 600. How moves to block 601 Where a more robust PHY mode is selected for the 45 existing connection. FloW proceeds to block 602 Where the base station. The CPEs and base station could be operated at control module 212 determines an air link line rate based on a reference PHY mode. FloW moves to block 603 Where the a more robust PHY mode than their planned PHY mode. control module calculates the hard bandWidth commitments for the existing connections betWeen the base station 102 and 50 based on the current PHY mode for each connection. FloW moves to a decision block 514 Where the precedence module 210 determines Whether the air link line rate determined at CPEs 104 based on the current PHY mode for each connec tion. FloW moves to a decision block 604 Where the prece dence module 210 determines Whether the air link line rate determined at block 602 exceeds the hard bandWidth com 55 mitments betWeen the CPEs and base station. If the air link line rate exceeds the hard bandWidth commitments, the pro cess continues to a block 606 Where the more robust PHY mode selected in block 601 is applied for the existing con nection. How then returns to block 402 of FIG. 4 Where the base station 102 receives the next uplink from a CPE 104. Returning to decision block 604, if the air link line rate does not exceed the hard bandWidth commitments, ?oW pro ceeds to a decision block 608 Where the precedence module FloW proceeds to block 512 Where the control module 212 determines the hard bandWidth commitments for the existing connections betWeen the base station 102 and CPEs 104 60 block 506 exceeds the hard bandWidth commitments betWeen the CPEs and base station determined at block 512. If the air link line rate exceeds the hard bandWidth commitments, the process continues to a block 516 Where the base station allo cates air link resources to the neW connection. How then returns to block 502 Where the base station 102 receives a request for a neW connection. Returning to decision block 514, if the air link line rate does not exceed the hard bandWidth commitments, ?oW pro ceeds to a decision block 518 Where the precedence module 210 determines Whether additional air link resources are 65 210 determines Whether additional air link resources are available. These additional air link resources can include available. These additional air link resources can include available bandWidth in the uplink subframe 302 and available available bandWidth in the uplink subframe 302 and available US 8,537,757 B2 17 18 bandwidth in the doWnlink subframe 304 (see FIG. 2). If instruct the modem section to receive the doWnlink data based on the current doWnlink PHY mode, Wherein the doWnlink PHY mode speci?es a modulation format and a forWard error correction technique used for transmission of doWnlink data. 2. A subscriber station as claimed in claim 1, Wherein the current doWnlink PHY mode is different from the preferred doWnlink PHY mode. 3 . A subscriber station as in claim 1, Wherein the DL quality additional air link resources are available, How proceeds to block 516 Where the base station allocates air link resources to the neW connection. How then returns to block 502 Where the base station 102 receives a request for a neW connection. Returning to decision block 518, if additional air link resources are not available, How moves to a block 520 Where the precedence module 210 suspends existing connections betWeen the base station 102 and the CPEs 104. As described above, the precedence module 210 can, for example, suspend parameter is the signal to noise ratio (SNR). connections only betWeen the base station and the affected 4. A subscriber station as in claim 3, Wherein a less robust CPE, randomly suspend connections betWeen the base station preferred doWnlink PHY mode is selected by the subscriber and all of the CPEs in a sector 106, or suspend connections betWeen the base station and all of the CPEs in the sector in a round-robin fashion. Alternatively, the neW connection is accepted into a suspended state since the precedence module 210 has already determined Which of the other connections are to be suspended. Further, the precedence module 210 can randomly suspend connections betWeen the base station and the CPEs that have a loWer precedence priority than other connections. Alternatively, the precedence module 210 can suspend the connections that have a loWer precedence priority in a round-robin fashion. The process moves to block 516 Where the base station allocates air link resources to the neW connection. How then returns to block 502 Where the base station 102 aWaits a request for a neW connection. station if the SNR value is above the ?rst and the second threshold. 5.A subscriber station as in claim 1, Wherein the DL quality parameter is the bit error rate (BER). 6. A subscriber station as in claim 5, Wherein a less robust preferred doWnlink PHY mode is selected by the subscriber 20 25 Returning to decision block 508, if the air link line rate does not exceed the hard bandWidth commitments, ?oW pro ceeds to a block 522 Where the CAC module 206 denies the neW connection. The process then returns to block 502 to 30 aWait the next request for a neW connection. The foregoing description details certain embodiments of the invention. It Will be appreciated, hoWever, that no matter hoW detailed the foregoing appears in text, the invention can be practiced in many Ways. As is also stated above, it should be noted that the use of particular terminology When describ ing certain features or aspects of the embodiments should not instruct the modem section to transmit the uplink data using the uplink PHY mode. 9. A subscriber station as claimed in claim 1, further com 35 40 uplink connection based on the uplink bandWidth allocated to the subscriber station and a planned uplink PHY mode. 45 11 . A subscriber station as claimed in claim 10, Wherein the control module is con?gured to suspend an uplink connection 1. A subscriber station for a Wireless communication sys tem comprising: based on the bandWidth allocated to the subscriber station and the priority of all uplink connections served by the subscriber a modem section con?gured to receive doWnlink data from a base station on a doWnlink link and to transmit uplink data to the base station on an uplink link shared With When less uplink bandWidth is available for the subscriber station on the uplink link than required to serve all uplink connections. 10. A subscriber station as claimed in claim 9, Wherein the control module is con?gured to limit establishment of a neW appended claims and any equivalents thereof. What is claimed is: prising a precedence module that interfaces With the modem module and the control module to apply a priority to one or more uplink connections established at the subscriber station be taken to imply that the terminology is being re-de?ned herein to be restricted to including any speci?c characteristics of the features or aspects of the embodiment With Which that terminology is associated. The scope of the embodiments should therefore be construed in accordance With the station if the BER value is under the second and the ?rst threshold. 7. A subscriber station as claimed in claim 1, Wherein the control section further selects the doWnlink PHY mode based on the subscriber station capabilities. 8. A subscriber station as claimed in claim 1, Wherein the control module is further con?gured to: identify in an UL sub-frame map received from the base station, a current uplink PHY mode selected for the subscriber station based on a UL quality parameter for the uplink data and the bandWidth available to the sub scriber station on the uplink link; and 50 station. 12. A method of communication in a Wireless communi cation system, comprising: other subscribers stations; a receive signal quality module con?gured to monitor a receiving at a subscriber station doWnlink data from a base station on a doWnlink link and transmitting uplink data to the base station on an uplink link shared With other doWnlink (DL) quality parameter for the doWnlink data providing a parameter value; and subscribers stations; a control section con?gured to: determine a preferred doWnlink physical (PHY) mode for the doWnlink data among a plurality of PHY monitoring a quality parameter for the doWnlink data and providing a parameter value; modes of different degrees of robustness, the pre determining a preferred doWnlink physical (PHY) mode ferred doWnlink PHY mode being de?ned betWeen a ?rst and a second threshold for the parameter value; instruct the modem section to transmit to the base station an indication of the preferred doWnlink PHY mode; identify in a DL sub-frame map received from the base station, a current doWnlink PHY mode selected for the subscriber station based on the preferred doWnlink PHY mode and the bandWidth available to the sub scriber station on the doWnlink link; and for the doWnlink data among a plurality of PHY modes 60 of different degrees of robustness, the preferred PHY mode being de?ned betWeen a ?rst and a second thresh old for the parameter value; transmitting to the base station an indication of the pre ferred PHY mode; 65 identifying in a DL sub-frame map received from the base station, a current doWnlink PHY mode selected for the subscriber station based on the preferred doWnlink PHY US 8,537,757 B2 19 20 mode and the bandwidth available to the subscriber sta tion on the doWnlink link; and 19. A method as claimed in claim 18, Wherein the current uplink and doWnlink PHY modes can be adapted indepen receiving the doWnlink data having the current doWnlink PHY mode, dently based on one or more parameters for the uplink and respectively doWnlink data. Wherein the doWnlink PHY mode speci?es a modulation format and a forward error correction technique used for transmission of doWnlink data. 13. A method as claimed in claim 12, Wherein the quality parameter is the signal to noise ratio (SNR), and Wherein a 20. A method as claimed in claim 18, Wherein the step of establishing a current uplink PHY mode comprises: receiving from the base station an indication of the quality of the uplink data and determining if the quality of uplink data is betWeen a ?rst and a second thresholds; selecting a less robust UL PHY mode than the current UL more robust preferred doWnlink PHY mode is provided by the subscriber station if the SNR value is under the ?rst and the second threshold. 14. A method as claimed in claim 12, Wherein the quality parameter is the bit error rate (BER). PHY mode if the quality of uplink data increased over the ?rst and second threshold; and selecting a more robust UL PHY mode than the current UL PHY mode if the quality of uplink data is decreased 15. A method as claimed in claim 14, Wherein a more robust preferred doWnlink PHY mode is selected by the sub scriber station if the BER value is above the second and the ?rst threshold. 16. A method of communication in a Wireless communi cation system, comprising: 20 receiving at a subscriber station doWnlink data from a base station on a doWnlink link and transmitting uplink data to the base station on an uplink link shared With other When a more robust UL PHY mode is selected: determining the amount of UL bandWidth available to the subscriber station using a reference PHY mode for the subscribers stations; monitoring a parameter for the doWnlink data and provid ing a parameter value; transmitting to the base station the parameter value for enabling the base station to establish a current doWnlink PHY mode for the subscriber station based on a ?rst and a second threshold for the parameter value and the doWnlink resources available to the subscriber station on 25 30 ment. the amount of UL bandWidth available to the subscriber sta 35 40 eter value is one of a BER value and a SNR value. 18. A method as claimed in claim 16, further comprising establishing a current uplink PHY mode for transmission of for transmission of uplink data. tion is less than the hard bandWidth commitment for the CPE, re-select a less robust uplink PHY mode Whenever addi tional bandWidth is allocated to the subscriber station from the base station; and suspend a connection established on the subscriber station if additional bandWidth is not available to the subscriber station. 24. A method as claimed in claim 20, further comprising, Wherein the bandWidth resulting from using a more robust UL PHY mode is reallocated to other CPEs or connection for UL uplink data, Wherein the uplink PHY mode speci?es a modu lation format and a forWard error correction technique used mode if the amount of UL bandWidth available to the subscriber station exceeds the hard bandWidth commit 23. A method as claimed in claim 22, further comprising, if identifying in a DL sub-frame map received from the base Wherein the doWnlink PHY mode speci?es a modulation format and a forWard error correction technique used for transmission of doWnlink data. 17. A method as claimed in claim 16, Wherein the param subscriber station; calculating a hard bandWidth commitment for all UL con nections currently established on the CPE, based on the current PHY mode; and transmitting the uplink data using the more robust PHY the down-link; and station, the current doWnlink PHY mode; and receiving the doWnlink data having the current doWnlink PHY mode, under the ?rst and second threshold. 21. A method as claimed in claim 18, Wherein the step of establishing a current uplink PHY mode further comprises maintaining the current UL PHY mode if the quality of the uplink data betWeen the ?rst and second thresholds. 22. A method as claimed in claim 20, further comprising, 45 transmission.

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