METHOD AND APPARATUS FOR ALLOWING SOFT HANDOFF OF A CDMA REVERSE LINK UTILIZING AN ORTHOGONAL CHANNEL STRUCTURE

• US 20110170467A1
• Filed: 03/22/2011
• Published: 07/14/2011
• Est. Priority Date: 07/19/2000
• Status: Active Grant

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Alapuranen, Bertti O., Proctor, James A. JR.
• Granted Patent: US 8,676,131 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/12 Generation of orthogonal codes
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 52/386 centralized, e.g. when the radio network controller or equivalent takes part in the power control
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

Method and apparatus for base stations and subscriber units allows soft handoff of a CDMA reverse link utilizing an orthogonal channel structure. Subscriber units transmit an orthogonally coded signal over a reverse link to the base stations. A given base station provides timing control of the timing offset of the reverse link signal. Based on at least one criterion, an alignment controller determines that the given base station should hand off timing control to another base station, and a soft handoff process ensues. In response to a command or message for soft handoff of the subscriber unit from the given base station to another base station, the subscriber unit makes a coarse timing adjustment to the timing of the coded signal. The subscriber unit may make fine timing adjustments based on feedback from the base station controlling timing. Multiple base stations may provide power control feedback to the subscriber unit.

Claims

1. A wireless subscriber unit comprising:

circuitry configured to transmit packet data in soft handover to a plurality of base stations;

wherein the packet data is transmitted using at least one orthogonal code and a pseudo noise (PN) code;

wherein the circuitry is further configured to receive commands from the plurality of base stations;

wherein the circuitry is further configured in response to the received commands, to adjust a power level associated with the transmission of the packet data;

wherein on a condition that any command from any of the plurality of base stations indicates a decrease in the power level, the power level is decreased;

wherein on a condition that at least one command from at least one of the plurality of base stations indicates an increase in the power level and no other base station sent a command indicating a decrease in power command, the power level is increased.

2. A method comprising:

transmitting, by a wireless subscriber unit, packet data in soft handover to a plurality of base stations;

wherein the packet data is transmitted using at least one orthogonal code and a pseudo noise (PN) code;

receiving, by the wireless subscriber unit, commands from the plurality of base stations;

in response to the received commands, adjusting, by the subscriber unit, a power level associated with the transmission of the packet data;

wherein on a condition that any command from any of the plurality of base stations indicates a decrease in the power level, the power level is decreased;

wherein on a condition that at least one command from at least one of the plurality of base stations indicates an increase in the power level and no other base station sent a command indicating a decrease in power command, the power level is increased.

3. A wireless subscriber unit comprising:

circuitry configured to transmit packet data in soft handover to a at least a first base station and a second base station;

wherein the packet data is transmitted using at least one orthogonal code and a pseudo noise (PN) code;

wherein the circuitry is further configured to receive a first command from at least one first base station and a second command from at least one second base station;

wherein the command from the at least one first base station is a plurality of bits;

wherein the plurality of bits indicates one of a plurality of power levels;

wherein the circuitry is further configured in response to the received first and second command, to adjust a power level associated with the transmission of the packet data;

wherein the power level is a lowest power level derived from the first command or the second command.

4. A method comprising:

transmitting, by a wireless subscriber unit, packet data in soft handover to a at least a first base station and a second base station;

wherein the packet data is transmitted using at least one orthogonal code and a pseudo noise (PN) code;

receiving, by the wireless subscriber unit, a first command from at least one first base station and a second command from at least one second base station;

wherein the command from the at least one first base station is a plurality of bits;

wherein the plurality of bits indicates one of a plurality of power levels; and

in response to the received first and second command, adjusting, by the wireless subscriber unit, a power level associated with the transmission of the packet data;

wherein the power level is a lowest power level derived from the first command or the second command.