Cellular Communications Equipment LLC v. Apple Inc. et al

Filing 1

COMPLAINT against AT&T Inc., AT&T Mobility LLC, Apple Inc., Boost Mobile, LLC, Cellco Partnership d/b/a Verizon Wireless, Sprint Corporation, Sprint Solutions, Inc., Sprint Spectrum L.P., T-Mobile US, Inc., T-Mobile USA, Inc., Verizon Communications, Inc. ( Filing fee $ 400 receipt number 0540-4484085.), filed by Cellular Communications Equipment LLC. (Attachments: # 1 Civil Cover Sheet, # 2 Exhibit A - U.S. Patent No. 6,377,804, # 3 Exhibit B - U.S. Patent No. 6,819,923, # 4 Exhibit C - U.S. Patent No. 7,215,962, # 5 Exhibit D - U.S. Patent No. 7,941,174, # 6 Exhibit E - U.S. Patent No. 8,055,820)(Ward, Thomas)

EXHIBIT D

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1111111111111111111111111111111111111111111111111111111111111
US007941174B2

United States Patent

(10)

Breuer et al.

(12)

(45)

(54)

METHOD FOR MULTICODE TRANSMISSION
BY A SUBSCRIBER STATION

(75)

Inventors: Volker Breuer, Biitzow (DE); Thomas
Ulrich, Bad Dfukheim (DE)

(73)

Assignee: Nokia Siemens Networks GmbH & Co.
KG, Munich (DE)

( *)

Notice:

Patent No.:
US 7,941,174 B2
Date of Patent:
May 10, 2011

(56)

References Cited
U.S. PATENT DOCUMENTS

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.c. 154(b) by 436 days.

(21)

Appl. No.:

11/667,595

(22)

PCT Filed:

Oct. 6, 2005

(86)

PCT No.:

PCT/EP2005/055037

§ 371 (c)(1),
(2), (4) Date:

(87)

Dec. 22, 2008

US 2009/0131027 Al

(51)
(52)
(58)

UE

Bl
A2

1112001
8/2002
6/2005
7/2005
8/2005
3/1999
4/2002

112003

Primary Examiner - Ajit Patel
(74) Attorney, Agent, or Firm - Staas & Halsey LLP

May 21,2009

(57)

(DE) ......................... 10 2004054626

Int. Cl.
H04B 7/00
(2006.01)
U.S. Cl. ........ 455/522; 370/335; 370/342; 370/329;
370/341; 455/422.1
Field of Classification Search ........................ None
See application file for complete search history.

DOD
DOD

03/001681

1211998

A2
A2

* cited by examiner

Foreign Application Priority Data

D
DOD

19823504
1 154667
1229755
1 545040
1365520
1564905
11-74834
2002-118515

International Search Report for International Application No. peTI
EP2005/055037; mailed Jan. 9, 2006.
English Abstract for JP 2004-320164 A, Published Nov. 11,2004.

Prior Publication Data

Nov. 11,2004

EP
EP
EP
EP
EP
JP
JP

OTHER PUBLICATIONS

PCT Pub. Date: May 18, 2006

(30)

FOREIGN PATENT DOCUMENTS
DE

WO

PCT Pub. No.: W02006/051026

(65)

6,266,321 Bl
7/2001 Pehkonen et al.
6,330,232 Bl * 1212001 Fapojuwo ..................... 370/342
6,865,393 Bl * 3/2005 Baum et al. ................ 455/452.2
200210012332 Al * 112002 Tiedemann et al. .......... 370/335
2004/0066795 Al * 4/2004 Zhang ........................... 370/442
2005/0281219 Al * 1212005 Kim et al ...................... 370/328
2008/0159184 Al * 7/2008 Niwano ........................ 370/278

ABSTRACT

In a radio communications system, several codes for transmitting messages are assigned to a subscriber station. A transmission power differential is determined between the total
maximum transmission power of the subscriber station for the
codes and the total transmission power of the subscriber
station for the codes at the beginning of a message transmission, (the differential being respected by the subscriber station), by a first one of the codes.

NODE B

19 Claims, 1 Drawing Sheet

u.s. Patent

D
DOD
DOD
DOD

~
UE

May 10, 2011

NODE B

US 7,941,174 B2

US 7,941,174 B2
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METHOD FOR MULTICODE TRANSMISSION
BY A SUBSCRIBER STATION

codes for transmitting messages. In this case the different
codes serve to distinguish different transmission channels
used by the subscriber station, such as, for example, to distinguish between channels for transmitting payload and signaling information, or to distinguish channels of different
servIces.

CROSS REFERENCE TO RELATED
APPLICATIONS
This application is based on and hereby claims priority to
German Application No.1 02004054626.6 filed on Nov. 11,
2004, the contents of which are hereby incorporated by reference.

SUMMARY
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BACKGROUND
Described below are methods for operating a radio communication system wherein a subscriber station is assigned a
first and a second code for the purpose of transmitting messages.
In radio communication systems, messages containing, for
example, voice information, image information, video information, SMS (Short Message Service), MMS (Multimedia
Messaging Service) or other data are transmitted between a
transmitting radio station and a receiving radio station via a
radio interface with the aid of electromagnetic waves.
Depending on the physical embodiment of the radio communication system, the radio stations in this case can be different
types of subscriber radio stations or network-side radio stations such as base stations. In a mobile radio communication
system at least some of the subscriber stations are mobile
radio stations. The electromagnetic waves are emitted by
carrier frequencies that lie in the frequency band provided for
the respective system.
Mobile radio communication systems are often embodied
as cellular systems, for example conforming to the GSM
(Global System for Mobile Communication) or UMTS (Universal Mobile Telecommunications System) standard, having
a network infrastructure formed of base stations, devices for
monitoring and controlling the base stations and further network-side equipment. Apart from these cellular, hierarchical
radio networks organized as wide area (supralocal) networks
there are also wireless local networks such as, for example,
WLAN s (Wireless Local Area Networks) having a radio coverage area that is generally considerably more limited geographically. The cells covered by the radio access points (AP:
Access Point) of the WLANs are usually small compared
with typical mobile radio cells. Examples of different standards for WLAN s are HiperLAN, DECT, IEEE 802.11, Bluetooth and WATM.
Access by subscriber stations to the common transmission
medium is controlled in radio communication systems by
multiple access (MA) methods/multiplex methods. With
these multiple access techniques the transmission medium
can be divided up between the subscriber stations in the time
domain (Time Division Multiple Access, TDMA), in the frequency domain (Frequency Division Multiple Access,
FDMA), in the code domain (Code Division MultipleAccess,
CDMA) or in the space domain (Space Division Multiple
Access, SDMA). Combinations of multiple access methods
are also possible.
With code division multiple access methods, subscriberspecific codes are used for communication with subscriber
stations, with the result that in the downlink direction the
respective subscriber station or, as the case may be, in the
uplink direction network-side devices can differentiate the
messages to or from the subscriber station from the messages
to or from other subscriber stations by establishing a correlation between the received signal and the subscriber-specific
code. It is possible for a subscriber station to use a plurality of

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An aspect is to disclose an efficient method for operating a
radio communication system wherein a subscriber station is
assigned a first and a second code for the purpose of transmitting messages. Devices for performing the method are
also to be presented.
According to a first method for operating a radio communication system, a subscriber station is assigned a plurality of
codes for transmitting messages. A transmit power difference
to be maintained by the subscriber station is determined
between on the one hand the total maximum transmit power
of the subscriber station for the plurality of codes and on the
other hand the total transmit power of the subscriber station
for the plurality of codes at the start of a message transmission
using a first of the plurality of codes.
According to a second method for operating a radio communication system wherein a subscriber station is assigned a
plurality of codes for transmitting messages, a previously
determined transmit power difference is maintained by the
subscriber station between on the one hand the total maximum transmit power of the subscriber station for the plurality
of codes and on the other hand the total transmit power of the
subscriber station for the plurality of codes at the start of a
message transmission using a first of the plurality of codes.
The subscriber station is assigned at least a first and a
second code for the purpose of transmitting messages. Each
of the different codes can be a combination of a plurality of
individual codes; thus, according to UMTS, for example, the
combination consisting of a spreading and a scrambling code.
In addition to the plurality of codes that are involved in the
method described below, further codes can also be used by the
subscriber station for the purpose of transmitting messages.
A transmit power difference which is to be maintained by
the subscriber station between a first and a second transmit
power is determined. A difference between two values is
maintained if the distance between the two values is greater
than or equal to the difference. The first of the two transmit
powers is the total maximum transmit power of the subscriber
station for the plurality of codes, i.e. the maximum transmit
power, when the subscriber station uses the plurality of codes
in parallel for transmitting messages. The maximum transmit
power for the parallel use of a plurality of codes is preferably
predetermined by the hardware of the subscriber station,
which is to say, for example, by the power amplifier which is
intended to amplifY in a linear manner but produces a nonlinear signal distortion in the power end range, for which
reason it is not used in the end range. It is, however, also
possible for the maximum transmit power for the parallel use
of a plurality of codes of the subscriber station to be predefined on the network side.
The second of the two transmit powers is the total transmit
power of the subscriber station for the plurality of codes at the
start of a message transmission using a first of the codes. This
corresponds to the sum of the transmit power for the first code
and the transmit power for the remaining code or codes, and
moreover in each case at the time of the start of the message
transmission using the first code. If no message transmission
using the remaining code or codes is performed precisely at
the time of the start of the message transmission using the first

US 7,941,174 B2

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code, but instead is only initiated a short time later, then the
transmit power for the remaining code or codes at the point in
time occurring a short time later can be used for the sum
forming operation described.
If messages are transmitted using the first code at specific
time intervals rather than continuously, the start of a time
interval of this kind corresponds to the start of the message
transmission using the first code. The method described
below can be applied in relation to any such start time, i.e. to
any message transmission using the first code, or to a subset
of the start times.
The radio communication system under consideration can
be a cellular mobile radio communication system, in particular a UTMS radio communication system, or also a local radio
communication system.
the transmit power difference may be detennined on the
network side and a base station sends the subscriber station a
message containing infonnation relating to the determined
transmit power difference. In this case the transmit power
difference is determined not by the subscriber station, but by
one or more devices of the infrastructure network of the radio
communication system, in particular by the base station.
After the network-side detennination of the transmit power
difference, information relating to the determined transmit
power difference is notified to the subscriber station so that
the subscriber station can extract the transmit power difference from the information or determine the transmit power
difference from the infonnation.
It is advantageous if the message to the subscriber station
also contains infonnation relating to a maximum data rate to
be used by the subscriber station for the message transmission
using the first code.
The transmit power difference may be determined as a
function ofa property of the base station and/or the radio cell
of the base station, and/or of an interference situation, and/or
of at least one service used by the subscriber station, and/or of
a classification of the subscriber station. In this way the transmit power difference can be defined differently from base
station to base station or, as the case may be, from radio cell
to radio cell under conditions that are otherwise identical.
With regard to the interference, the interference within the
cell to which the subscriber station is assigned, and/or within
cells adjacent to this cell, can be taken into account. It is
advantageous in particular to take into account the type of
service used by the subscriber station by transmitting messages using the first code during the determination of the
transmit power difference. Subscriber stations can be classified or prioritized on the network side and handled in accordance with this classification during the determination of the
transmit power difference.
The transmit power difference may be detennined by the
subscriber station. This difference can be determined in particular as a function of a plurality of transmit powers used in
the past by the subscriber station for a second code, in particular using the variance of these transmit powers. This taking into account of the transmit powers used in the past can
also be indirect, in that power control infonnationreceived by
the subscriber station in respect of the transmit powers used
for the second code is used.
The network-side device and the subscriber station can
have a transmit power difference which is to be maintained by
the subscriber station between, on the one hand, the total
maximum transmit power of the subscriber station for the
plurality of codes and, on the other hand, the total transmit
power of the subscriber station for the plurality of codes at the
start of a message transmission using a first of the plurality of
codes.

In addition or alternatively, the subscriber station can
maintain a previously determined transmit power difference
between, on the one hand, the total maximum transmit power
of the subscriber station for the plurality of codes and, on the
other hand, the total transmit power of the subscriber station
for the plurality of codes at the start of a message transmission
using a first of the plurality of codes.
BRIEF DESCRIPTION OF THE DRAWINGS
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These and other objects and advantages will become more
apparent and more readily appreciated from the following
description of an exemplary embodiment, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a pictorial diagram of a portion of a radio communication system.
DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENT
Reference will now be made in detail to the preferred
embodiments, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals
refer to like elements throughout.
FIG. 1 shows a section of a UMTS radio communication
system with a subscriber station UE (UE: User Equipment)
and a base station NODE B. The base station NODE B is
connected to further network-side devices of the infrastructure network NET. In the uplink (UL) direction the communication, i.e. the message transmission from the subscriber
station UE to the base station NODE B, takes place on a
dedicated channel, described, for example, in [3GPP TS
25.211 V6.2.0, 3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; Physical channels and mapping of transport channels onto physical channels (FDD)]. For this purpose the subscriber station UE is
assigned the code DCH. A second code EDCH (Enhanced
Dedicated Uplink Channel) is assigned to the subscriber station UE, in particular for transmitting high bit rate traffic.
In order to regulate the power in accordance with a closed
loop power control, the base station NODE B sends the subscriber station UE power control instructions, the TPC bits, at
regular intervals, i.e. information as to whether the transmit
power is to be increased or decreased by the subscriber station
UE. The subscriber station UE is subject to a maximum value
for the transmit power which cannot be exceeded. In deteriorating radio transmission conditions the subscriber station UE
is requested by the base station NODE B to increase its
transmit power. The transmit power can be increased at most
up to the maximum value of the transmit power of the subscriber station UE. If the subscriber station UE receives a
further request to increase its transmit power after reaching
the maximum value of its transmit power, it can adjust the
TFC (Transport Fonnat Combination) used by it. For each
physical channel the TFC specifies the ratio of coded data, i.e.
the total data, to the payload data, and consequently the data
rate. For a given radio channel each TFC is uniquely linked to
a transmit power. Under constant radio traffic conditions,
therefore, a switch to a TFC with a lower data rate corresponds to a switch to a lower transmit power. In order to
comply with the request of the base station NODE B for a
transmit power increase, the subscriber station UE can thus
switch to a TFC with a lower data rate and leave the transmit
power unchanged or reduce it. The switching of a TFC can
only take place at specific times, and moreover at specific TTl
limits (TTl: Transmission Time Interval).

US 7,941,174 B2

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If the subscriber station UE uses not just the code DCH, but
the two codes EDCH and DCH in parallel, the situation in
which the subscriber station UE reaches the maximum value
of its transmit power occurs more often than if the subscriber
station UE uses only the code DCH. There are the following
reasons for this:
The total transmit power of the subscriber station UE when
using a plurality of codes is produced from the sum of
the transmit powers of the individual codes. The total
transmit power of the subscriber station UE is therefore
higher on average, the more codes it uses.
The code EDCH is intended to be used for transmitting
high bit rate data packets to the base station NODE B. In
keeping with the link between data rate and transmit
power via the TFC, the subscriber station UE requires a
higher transmit power for the code EDCH than for the
code DCH.
If the subscriber station UE uses the two codes EDCH and
DCH in parallel, the maximum value of the transmit
power can be reduced compared with the case where it
uses only the code DCH. The reason for this is that in a
multicode transmission the PAR value (PAR: Peak to
Average Ratio) can be worse. This reduction in the maximum transmit power in a multi code transmission applies
to most subscriber stations; if this reduction were to be
avoided, higher requirements in terms of the linearity of
the amplifiers of the subscriber stations would be necessary.
The length of an EDCH message (TTl: Transmission Time
Interval) is 10 ms. During this time the subscriber station UE
receives 15 TPC bits. The TFC for the code EDCH cannot be
changed during the TTl, i.e. the subscriber station UE can
respond to an instruction from the base station NODE B to
increase its transmit power only by increasing the transmit
power; adjusting the TFC for the code EDCH is not possible
during the transmission of an EDCH message. Another possible way to respond to the request from the base station
NODE B to increase the transmit power is to adjust the TFC
for the code DCH. This can be switched by the subscriber
station UE at the start of a TTl for the code DCH. The times
of the TTl start of the two codes DCH and EDCH can be
different from each other. In this way it is possible for the
subscriber station UE to comply with the request to increase
the transmit power during the transmission of an EDCH message by changing the TFC for the code DCH and thereby
enabling the transmit power for the code EDCH to be
increased if a suitable TTl limit for switching over the TFC is
present. This is only possible, however, if the subscriber station UE is not already using the lowest possible data rate for
the code DCH. However, this smallest TFC corresponding to
the lowest possible data rate is always used by the subscriber
station UE when it has little data to be transmitted using the
code DCH.
If when using the two codes EDCH and DCH the subscriber station UE reaches the (reduced) maximum value of
the transmit power during the transmission of an EDCH message, and if it receives instructions from the base station
NODE B to continuously increase its transmit power, it must
abort the transmission of the EDCH message before the end
of the EDCH message if an adjustment of the TFC of the code
DCH is not possible. Aborting the message transmission of
the code DCH is not possible, for if the base station NODE B
can no longer receive the messages of the code DCH, the
connection between the base station NODE B and the subscriber station UE is interrupted, with the result that the
maintaining of the communication using the code DCH for
upholding the connection between subscriber station UE and

base station NODE B is indispensable. Aborting the transmission of the EDCH message means wasting radio
resources, since the incomplete EDCH message cannot be
evaluated on the network side, yet interference has been generated due to the incomplete transmission of the EDCH message.
The subscriber station UE is notified by the base station
NODE B prior to the transmission of an EDCH message of
which TFC may be used at a maximum for this transmission,
i.e. the maximum possible data rate for the EDCH message.
Before the transmission of the EDCH message the subscriber
station UE specifies a TFC which will be used for the EDCH
message, taking into account that the maximum data rate
assigned to it by the base station NODE B may not be
exceeded. According to the radio traffic conditions or, as the
case may be, the radio charmel between the subscriber station
UE and the base station NODE B, a specific transmit power
for the transmission of the EDCH message is linked to the
selected TFC under constant propagation conditions.
If the subscriber station UE chooses a high data rate and
therefore a high transmit power for the transmission of the
EDCH message, it is possible that it will receive a request to
increase the transmit power several times during the transmission of the EDCH message, which ultimately can lead, as
described in the foregoing, to the abortion of the transmission
of the EDCH message since the maximum transmit power of
the subscriber station UE would have been exceeded. If, on
the other hand, the subscriber station UE chooses a low data
rate and therefore a low transmit power for the transmission of
the EDCH message, it is possible that ifthere are few requests
to increase the transmit power a large part of the total transmit
power available to the subscriber station UE will not be used
and consequently a lower data rate was used for the EDCH
message than would be possible and desirable from the point
of view of the subscriber station UE. In selecting the TFC for
the transmission of an EDCH message a compromise must
therefore be found between a high data rate for the EDCH
message and a reliable, i.e. complete, transmission of the
EDCH message.
In order to solve this problem, it is proposed that a transmit
power difference which is to be maintained by the subscriber
station UE be determined by the base station NODE B. The
transmit power difference, which can be termed the "power
headroom", is required to exist between the total transmit
power for the two codes DCH and EDCH at the start of the
transmission of an EDCH message and the maximum transmit power for the two codes DCH and EDCH. The transmit
power difference thus corresponds to an nnused transmit
power at the start of the transmission of an EDCH message.
For illustration purposes a numeric example will be considered:
The maximum transmit power of the subscriber station UE
when using only the code DCH, i.e. without multicode
transmission, is 21 dBm.
Let the maximum transmit power of the subscriber station
UE when using the two codes DCH and EDCH be
reduced by 3 dB compared to the maximum transmit
power when using only one code, i.e. it amonnts to 21
dBm-3 dB=18 dBm.
For the code DCH let the subscriber station UE use the
minimum possible data rate, this corresponding to a
transmit power for the code DCH of 3 dBm given a
specific assumed radio propagation condition. Thus, a
maximum of18 dBm-3 dB=15 dBm is available for the
codeEDCH.
Let the base station NODE B specifY a transmit power
difference of 8 dB for the subscriber station UE. This

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yields the maximum transmit power to be used by the
subscriber station UE at the start of the transmission of
the EDCH message as: 18 dBm-3 dB-8 dB=7 dBm.
The transmit power difference can be determined in the
base station NODE B as a function of a number of parameters:
The Type of Cell of the Base Station NODE B.
A distinction can be made between "capacity limited" and
"coverage limited" cells. A "capacity limited" cell is a cell in
which the transmit power of the base station that is to be
divided up among the subscriber stations in the downlink
direction is the limiting factor for the cell size. This applies
mostly to small cells in urban areas. The subscriber stations in
such cells generally transmit at low transmit power, so the
maximum transmit power of the subscriber stations is seldom
reached. No large "power headroom" must therefore be set
for a "capacity limited" cell, i.e. a base station of a "capacity
limited" cell defines only small transmit power differences. A
"coverage limited" cell is a cell in which the transmit power of
the subscriber stations in the uplink direction is the limiting
factor for the cell size. This applies mostly to large cells in
rural areas. Since the subscriber stations of a "coverage limited" cell frequently reach their maximum transmit power, a
large "power headroom" should be set at the start of the
transmission of an EDCH message to ensure that sufficient
scope for increasing the transmit power during the transmission of the EDCH message is present. A base station of a
"coverage limited" cell will therefore define high transmit
power differences.
The Current Interference Situation in the Cell or in an Area
Formed by a Plurality of Cells.
The greater the current interference in a cell and/or in the
surrounding cells, the higher the transmit power differences
should be specified. The consequence of this is that subscriber
stations which are located in the vicinity of the receiving base
station and which therefore require a low transmit power and
so generate little interference receive preference, i.e. achieve
greater data rates for the EDCH messages than the more
remote subscriber stations. Owing to the fact that the subscriber stations in the vicinity of the base station must use
only low transmit powers to achieve high data rates, their
EDCH transmissions scarcely experience any restrictions due
to large transmit power differences. In contrast, subscriber
stations which are very distant from the base station are
subject to restrictions in respect of the transmission ofEDCH
messages, since only a low data rate is possible for the EDCH
messages due to the great distance from the receiving base
station or during the soft handover to the receiving base
stations and due to the high transmit power difference, with
the consequence that many of these subscriber stations must
forego the transmission of EDCH messages. As a result the
subscriber stations generate little interference in the surrounding cells. Specifying the transmit power difference thus
represents a controlling intercell interference.
The Service Used by a Subscriber Station in Respect of the
CodeEDCH.
A distinction can be made between two basic types of
services. Firstly there are services in which a minimum service rate is guaranteed (referred to as the Guaranteed Bit Rate,
or GBR). These can be realtime services in which a reliable
transmission is necessary, such as, for example, videotelephony and online gaming. A high transmit power difference
should be specified for these services so that even if the radio
channel deteriorates during the transmission of an EDCH
message this can be made up for by an increase in the transmit
power and the EDCH message can be transmitted without
having to be aborted. Secondly there are services in which a
high data rate is required, while an occasional breakdown in

the transmission of an EDCH message does not have an
overly negative impact. The aborted EDCH messages can be
transmitted in full at a later time. Examples of this are nonrealtime games. A low transmit power difference should be
specified for the latter-mentioned services to ensure that a
high data rate (maximum throughput) can be achieved for the
EDCH messages.
The Strategy of the Network Operator in Respect of the
EDCH.
If a high data throughput is to be achieved overall for all
users via the EDCH, low transmit power differences should
be defined by the base stations.
The Class of the Subscriber Station.
The subscriber stations can be classified, with subscriber
stations belonging to a higher priority class having to maintain a lower transmit power difference than subscriber stations belonging to a lower priority class. Threshold values, for
example, can be used as maximum values of the transmit
power difference for subscriber stations belonging to certain
classes. The lowering of the transmit power difference as the
priority of the subscriber stations increases can be explained
by the fact that the base station must divide up the total
interference that is tolerable for the EDCH at its receiver for
the EDCH channel of all subscriber stations between the
subscriber stations. In particular the subscriber stations which
are at a great distance from the base station generate an
increased amount of interference. Using a low transmit power
difference, a high priority subscriber station is allocated a
large proportion of the interference that is to be divided up
between the subscriber stations. When a high transmit power
difference is to be maintained a subscriber station can decide
that the respective data rate for the EDCH message is so small
that it will dispense with the transmission of the EDCH message. If a high value for the transmit power difference is
determined for the subscriber stations when a high level of
interference is present, it is possible at these times for EDCH
messages to be transmitted only by subscriber stations which
have been assigned a high priority, since the defined transmit
power difference is too high for the transmission of an EDCH
message for the lower priority subscriber stations. The classification can have an effect on the billing of the respective
subscriber.
When determining the transmit power difference the base
station NODE B can use one of the described parameters or
combinations of the parameters. The transmit power difference can be determined on a subscriber-station-specific basis,
i.e. for individual subscriber stations, or for a group of subscriber stations or for all subscriber stations which use a code
EDCH.
The transmit power difference is signaled to the subscriber
station UE by the base station NODE B. It is possible that the
subscriber station UE has to maintain the transmit power
difference exactly, i.e. that the sum formed from the transmit
powers for the two codes DCH and EDCH at the start of the
transmission of the EDCH message differs from the maximum transmit power available for the two codes DCH and
EDCH precisely by the transmit power difference, or that the
transmit power difference defined by the base station NODE
B represents a minimum value which must be present at least
between the sum of the transmit powers for the two codes
DCH and EDCH at the start of the transmission of the EDCH
message and the maximum transmit power available for the
two codes DCH and EDCH. The determined transmit power
difference can be signaled using a message introduced specifically for these purposes, though the information relating to
the transmit power difference can also be integrated into
another message. It is advantageous in particular if a message

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is sent from the base station NODE B to the subscriber station
UE containing both the specification of the transmit power
difference requiring to be maintained and the specification of
the TFC with the maximum data rate that may be used by the
subscriber station UE for the respective transmission of the
EDCH message. If the same transmit power difference is
determined for a plurality of subscriber stations, these can be
informed of the defined transmit power difference in a joint
notification.
While the case has been described in which the transmit
power difference is detennined by the base station, the transmit power difference can also be determined by a device
controlling the base station NODE B, such as, for example, by
a CRNC (Controlling RNC). This device then informs the
base station NODE B of the defined transmit power difference. As described above in relation to the message transmission between base station and subscriber station, the information relating to the defined transmit power difference is
preferably contained in a message which also includes the
specification of the TFC with the maximum data rate that may
be used by the subscriber station for the respective transmission of the EDCH message.
As an alternative to the transmit power difference being
defined by the base station NODE B, it can also be determined
by the subscriber station UE. In this case the subscriber station UE can take into account the instructions received in the
past concerning the transmit power control in relation to the
code DCH, i.e. the TPC bits. Ifthe transmit power for the code
DCH within a specific period of time in the past lies, for
example in the range between -10 dBm and + 10 dBm, i.e. if
the transmit power for the code DCH exhibits a great variance, the transmit power difference will be defined as a higher
value by the subscriber station UE than in the case of a small
variance, which is to say, for example, if the transmit power
for the code DCH within the specific period of time in the past
lies in the range between -3 dBm and +3 dBm. Thus, the
variance of the transmit powers of a first channel, of the code
DCH, is used to determine the transmit power for a second
channel, for the code EDCH. The actual value for the transmit
power of the code EDCH is determined by the subscriber
station from the transmit power difference, the current value
of the transmit power for the code DCH, the TFC for the code
EDCH, the maximum value of which is predefined for it by
the base station NODE B, its maximum transmit power for
multicode transmission, and the current radio transmission
conditions.
A description has been provided with particular reference
to preferred embodiments thereof and examples, but it will be
understood that variations and modifications can be effected
within the spirit and scope of the claims which may include
the phrase "at least one of A, B and C" as an alternative
expression that means one or more ofA, B and C may be used,
contrary to the holding in Superguide V. DlRECTV, 358 F3d
870,69 USPQ2d 1865 (Fed. Cir. 2004).
The invention claimed is:
1. A method for operating a radio communication system in
which a subscriber station is assigned a plurality of codes for
transmitting messages, comprising:
detennining a transmit power difference which is to be
maintained by the subscriber station between on one
hand a total maximum transmit power of the subscriber
station for the codes and on another hand a total transmit
power of the subscriber station for the codes at a start of
a message transmission using a first one of the codes.
2. The method as claimed in claim 1,
wherein said detennining of the transmit power difference
is perfonned by a network device, and wherein said

method further comprises sending from a base station to
the subscriber station a message containing infonnation
relating to the transmit power difference as determined
by the network device.
3. The method as claimed in claim 2, wherein the message
to the subscriber station contains information relating to a
maximum data rate to be used by the subscriber station for the
message transmission using the first code.
4. The method as claimed in claim 3, wherein said determining of the transmit power difference is based on a function
of at least one of a property of the base station, a property of
a radio cell of the base station, an interference situation, at
least one service used by the subscriber station, and a classification of the subscriber station.
5. The method as claimed in claim 2, wherein said determining of the transmit power difference is based on a function
of at least one of a property of the base station, a property of
a radio cell of the base station, an interference situation, at
least one service used by the subscriber station, and a classification of the subscriber station.
6. The method as claimed in claim 1, wherein said determining of the transmit power difference is performed by the
subscriber station.
7. The method as claimed in claim 6, wherein said determining of the transmit power difference is based on a function
of a plurality of transmit powers used previously by the subscriber station for a second of the codes.
8. The method as claimed in claim 7, wherein the radio
communication system is a Universal Mobile Telecommunications System radio communication system.
9. A method for operating a radio communication system in
which a subscriber station is assigned a plurality of codes for
transmitting messages, comprising:
maintaining a previously detennined transmit power difference by the subscriber station between on one hand a
total maximum transmit power of the subscriber station
for the codes and on another hand a total transmit power
of the subscriber station for the codes at a start of a
message transmission using a first one of the codes.
1 0. The method as claimed in claim 9, wherein the transmit
power difference is determined on the network side and a base
station sends the subscriber station a message containing
information relating to the defined transmit power difference.
11. The method as claimed in claim 10, wherein the message to the subscriber station contains infonnation relating to
a maximum data rate to be used by the subscriber station for
the message transmission using the first code.
12. The method as claimed in claim 11, wherein said determining of the transmit power difference is based on a function
of at least one of a property of the base station, a property of
a radio cell of the base station, an interference situation, at
least one service used by the subscriber station, and a classification of the subscriber station.
13. The method as claimed in claim 10, wherein said determining of the transmit power difference is based on a function
of at least one of a property of the base station, a property of
a radio cell of the base station, an interference situation, at
least one service used by the subscriber station, and a classification of the subscriber station.
14. The method as claimed in claim 9, wherein said determining of the transmit power difference is performed by the
subscriber station.
15. The method as claimed in claim 14, wherein said determining of the transmit power difference is based on a function
of a plurality of transmit powers used previously by the subscriber station for a second of the plurality of codes.

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US 7,941,174 B2
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16. The method as claimed in claim 15, wherein the radio
communication system is a Universal Mobile Telecommunications System radio communication system.

18. A subscriber station for a radio communication system,
the subscriber station assigned a plurality of codes for transmitting messages, comprising:
at least one processor programmed to determine a transmit
power difference which is to be maintained by the subscriber station between on one hand a total maximum
transmit power of the subscriber station for the codes
and on another hand a total transmit power of the subscriber station for the codes at a start of a message
transmission using a first one of the codes.
19. A subscriber station as claimed in claim 18, wherein
said at least one processor is further programmed to maintain
the transmit power difference.

17. A base station in a radio communication system in
which a subscriber station is assigned a plurality of codes for
transmitting messages, comprising:

at least one processor programmed to determine a transmit
power difference which is to be maintained by the subscriber station between on one hand a total maximum
transmit power of the subscriber station for the codes
and on another hand a total transmit power of the subscriber station for the codes at a start of a message
transmission using a first one of the codes.

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