Signal acquisition in a multi-user communication system using multiple walsh channels

Claim 3

The method of claim 1 wherein said altering step further comprises the step of determining when said combining results exceed at least two predetermined threshold values.

Claim 4

The method of claim 1 wherein the step of combining comprises accumulating square products and summing them together over an interval commencing and ending at said Walsh function boundaries.

Claim 5

The method of claim 1 wherein the channel signal to be acquired is a pilot channel signal.

Claim 6

The method of claim 1 wherein the channel signal to be acquired is a paging channel signal.

Claim 7

The method of claim 1 wherein the channel signal to be acquired is a relatively strong traffic channel signal.

Claim 8

The method of claim 1 wherein said coherent accumulation occurs over an interval L/2 n long, with L being the length of Walsh functions used, and a pilot signal is transferred over a first channel and relatively strong signals are preferentially transferred on channels that are spaced apart from the first channel by increments of sL/2 n , where n is a positive integer and s equals 1 through 2 n -1.

Claim 9

The method of claim 7 wherein said Walsh functions have a length of 128 chips and a pilot signal is transferred over channel 0 while communications traffic is transferred over channels 32, 64, and 96.

Claim 10

The method of claim 7 wherein said orthogonal codes are Walsh functions of length 128 and a pilot signal is transferred over channel 1 while communications traffic is transferred over channels 33, 65, and 97.

Claim 11

The method of claim 7 wherein said strong signals comprise a paging signal.

Claim 12

The method of claim 7 wherein said Walsh functions have a length of 128 chips and a pilot signal is transferred over channel 0 while paging signals are transferred over at least one of channels 32, 64, and 96.

Claim 13

The method of claim 7 wherein said strong signals comprise a synchronization signal.

Claim 14

Apparatus for acquiring time synchronization with one or more orthogonal channel signals in a spread spectrum communication system in which one or more communication signals are received and demodulated by system subscribers, comprising: a receiver for receiving one or more communication signals each comprising channel signals which are orthogonally encoded using one of a preselected set of Walsh functions which are spread using at least one common pseudorandom noise (PN code) sequence applied at one of a plurality of timing offsets relative to each other within said system; means for selecting a PN code sequence time offset value and for generating said PN sequence with said selected time offset, being responsive to a reselect input for altering said selected time offset value and re-generating said PN code sequence with said altered time offset value; a signal despreader connected to receive communication signals and said PN sequence, and despread said communication signals into encoded symbols by applying said PN code sequence at said chosen time offset; a coherent accumulator connected to receive encoded symbols and to sum amplitudes for encoded symbols together over a predetermined time interval equivalent to the length of said Walsh functions divided by 2 n , where n is a positive integer; product means connected to said coherent accumulator for receiving and squaring the summation results; means for combining connected to receive and integrate square products over an interval commencing and ending at Walsh function boundaries as selected by the receiving subscriber unit; means for comparing connected to receive and to compare results of said integration to at least one threshold value; and means for generating a reselect command connected to said means for selecting and generating, and to said means for comparing, for generating a reselect command after a comparison to a threshold when said threshold is not exceeded.

Claim 15

Apparatus for acquiring time synchronization with one or more orthogonal channel signals in a spread spectrum communication system in which one or more communication signals are received and demodulated by system subscribers, comprising: a receiver for receiving one or more communication signals each comprising channel signals which are orthogonally encoded using one of a preselected set of Walsh functions which are spread using at least one common pseudorandom noise (PN code) sequence applied at one of a plurality of timing offsets relative to each other within said system; means for selecting a PN code sequence time offset value and for generating said PN sequence with said selected time offset, being responsive to a reselect input for altering said selected time offset value and re-generating said PN code sequence with said altered time offset value; a signal despreader connected to receive communication signals and said PN sequence, and despread said communication signals into encoded symbols by applying said PN code sequence at said chosen time offset; a coherent accumulator connected to receive encoded symbols and to sum amplitudes for encoded symbols together over a predetermined time interval equivalent to the length of said Walsh functions divided by 2 n , where n is a positive integer; product means connected to said coherent accumulator for receiving and squaring the summation results; means for combining connected to receive and integrate square products over an interval commencing and ending at Walsh function boundaries as selected by the receiving subscriber unit; means for comparing connected to receive and to compare results of said integration to at least one threshold value; and means for generating a reselect command connected to said means for selecting and generating, and to said means for comparing, for generating a reselect command after a comparison to a threshold when said threshold is not exceeded.

Claim 16

The apparatus of claim 13 wherein said means for comparing uses at least two predetermined threshold values.

Claim 17

The apparatus of claim 13 wherein said means for combining comprises at least one accumulation element for storing and adding together square products over an interval commencing and ending at said Walsh function boundaries.

Claim 18

The apparatus of claim 13 wherein the channel signal to be acquired is a pilot channel signal.

Claim 19

The apparatus of claim 13 wherein the channel signal to be acquired is a paging channel signal.

Claim 20

The apparatus of claim 13 wherein the channel signal to be acquired is a relatively strong traffic channel signal.

Claim 21

The apparatus of claim 13 wherein said accumulation occurs over an interval of length L/2 n , where L is the length of Walsh functions used, a pilot signal is transferred over a first channel and relatively strong signals are preferentially transferred on channels that are spaced apart from the first channel by increments of sL/2 n , where n is a positive integer and s equals 1 through 2 n -1.

Claim 22

The apparatus of claim 19 wherein said Walsh functions have a length of 128 chips and a pilot signal is transferred over channel 0 while traffic is transferred over channels 32, 64, and 96.

Claim 23

The apparatus of claim 19 wherein said Walsh functions have a length of 128 chips and a pilot signal is transferred over channel 1 while traffic is transferred over channels 33, 65, and 97.

Claim 24

The apparatus of claim 19 wherein said strong signals comprise a paging signal.

Claim 25

The apparatus of claim 19 wherein said strong signals comprise a synchronization signal.