Tdd base station for code group synchronization

Abstract

A time division duplex (TDD) base station having a code group out of N code groups includes circuitry configured to transmit a primary synchronization code along with a plurality of secondary synchronization codes. The plurality of synchronization codes are quadrature phase shift keying modulated and number less than (log 2 N)+1. The plurality of synchronization codes are used to identify the code group of the TDD base station.

What is claimed is: 
     
         1 . An integrated circuit (IC), implemented in a time division duplex (TDD) base station having a code group out of N code groups, the IC comprising:
 circuitry configured to output for transmission a primary synchronization code along with a plurality of secondary synchronization codes, the plurality of secondary synchronization codes being quadrature phase shift keying modulated and numbering less than (log 2 N)+1, and wherein the plurality of synchronization codes are used to identify the code group of the TDD base station.   
     
     
         2 . The IC of  claim 1  wherein N is equal to 32 code groups. 
     
     
         3 . The IC of  claim 2  wherein the 32 code groups are divided into two code group sets and a first of the code group sets has codes 1-16 and a second of the code group sets has codes 17-32. 
     
     
         4 . The IC of  claim 1  wherein the secondary synchronization codes are derived from a row of a Hadamard matrix. 
     
     
         5 . The IC of  claim 1  wherein the secondary synchronization signals are transmitted either on an in-phase or quadrature carrier. 
     
     
         6 . An integrated circuit (IC), implemented in a time division duplex (TDD) user equipment (UE) configured to synchronize to a TDD base station, the IC comprising:
 circuitry configured to receive a signal from the TDD base station;   circuitry configured to determine a primary synchronization code from the received signal;   circuitry configured to determine a first plurality of secondary synchronization codes sent on a first carrier from the received signal, wherein the first plurality of secondary synchronization codes are quadrature phased shift keyed (QPSK) modulated and the first carrier is an in-phase (I) carrier;   circuitry configured to determine a second plurality of secondary synchronization codes sent on a second carrier from the received signal, wherein the second plurality of secondary synchronization codes are QPSK modulated and the second carrier is a quadrature (Q) carrier; and   circuitry configured to determine a code group assignment and selected timeslot based upon an analysis of the secondary synchronization codes sent on the first and second carriers.   
     
     
         7 . The IC of  claim 6  wherein each of the first and second plurality of secondary synchronization codes correspond to a row of a Hadamard matrix. 
     
     
         8 . The IC of  claim 6  wherein there are 32 code groups. 
     
     
         9 . The IC of  claim 8  wherein the first plurality of secondary synchronization codes is assigned to a first group of codes out of the 32 code groups and the second plurality of secondary synchronization codes is assigned to a second group of codes out of the 32 code groups. 
     
     
         10 . The IC of  claim 9  wherein the first plurality of secondary synchronization codes is assigned to a lower group and the second plurality of secondary synchronization codes is assigned to a higher group. 
     
     
         11 . A time division duplex (TDD) system for synchronizing a TDD user equipment (UE) to a TDD base station, the system including a UE and a base station, the system comprising:
 the UE comprising:
 a receiver configured to receive a primary synchronization code along with a plurality of secondary synchronization codes from a TDD base station, the TDD base station associated with having a code group out of N code groups, the plurality of secondary synchronization codes numbering less than (log 2 N)+1 and the secondary synchronization codes being quadrature phase shift keying modulated; and 
 a corresponding matched filter to each of the received secondary synchronization codes; and 
 wherein the UE is configured to identify the code group of the TDD base station by the received plurality of secondary synchronization codes; and 
   the base station comprising:
 an antenna and associated circuitry configured to transmit a primary synchronization code along with a plurality of secondary synchronization codes, the plurality of secondary synchronization codes being quadrature phase shift keying modulated and numbering less than (log 2 N)+1, and wherein the plurality of synchronization codes are used to identify the code group of the TDD base station. 
   
     
     
         12 . The system of  claim 11  wherein N is equal to 32 code groups. 
     
     
         13 . The system of  claim 12  wherein the 32 code groups are divided into two code group sets and a first of the code group sets has codes 1-16 and a second of the code group sets has codes 17-32. 
     
     
         14 . The system of  claim 11  wherein the secondary synchronization codes are derived from a row of a Hadamard matrix. 
     
     
         15 . The system of  claim 11  wherein the secondary synchronization signals are transmitted either on an in-phase or quadrature carrier.