Multichannel CDMA subtractive interference cancellation method employed by a base station

• US 7,161,919 B2
• Filed: 06/06/2002
• Issued: 01/09/2007
• Est. Priority Date: 04/22/1993
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Schilling, Donald L., Kowalski, John
• Primary Examiner(s): Chin; Wellington
• Assistant Examiner(s): Boakye; Alexander O.
• Application Number:
  US10/163,790
• Publication Number:
  US 20020172172A1
• Time in Patent Office: 1,678 Days
• Field of Search: 370/342, 370/441, 370/201, 370/333, 370/335, 370/310, 370/479, 370/331, 370/332, 375/343, 375/347, 375/346, 375/206, 375/207
• US Class Current: 370/335
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/71075 Parallel interference cancellation

Abstract

A method employed by a base station wherein a plurality of channels are received as a received signal. Each channel is associated with a code. For each of the plurality of channels, others of the plurality of channels are subtracted from the received signal and a result of that subtracting is despread as data for that channel.

Claims

1. A method employed by a base station for recovering data transmitted over a plurality of channels employing wireless code division multiple access communication, comprising:

a) receiving the plurality of channels as a received signal, each channel associated with a code; and

b) subtracting for each of the plurality of channels others of the plurality of channels from the received signal and despreading a result of that subtracting by a delayed version for a first chip-code signal by a first channel mixer and filtered by a first channel filter, as data for that channel; and

c) respreading that channel despread signal with a respective channel code;

wherein the respreading channel code is aligned to a timing of the despread received signal;

wherein despreading the result further comprises passing the result of the subtractor through a mixer together with a code of a channel excluded from the subtraction operation.

2. The method of claim 1 wherein despreading the result further comprises filtering a result of the subtraction employing a code which is matched to a code of the channel excluded from the subtraction operation.

3. The method of claim 1 wherein steps (a) and (b) are repeated employing the despread result obtained during initial performance of steps (a) and (b).

4. The method of claim 3 further comprising combining the result from the repeated operation of steps (a) and (b) and passing the combined results through a decision device.