Digital radio systems

• US 8,270,456 B2
• Filed: 07/26/2007
• Issued: 09/18/2012
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: MStar Semiconductor Incorporated (MediaTek, Inc.)
• Inventors: Leach, Martin, Valadon, Cyril, Campbell, Neil Colin
• Primary Examiner(s): Joseph, Jaison
• Application Number:
  US12/373,998
• Publication Number:
  US 20100014614A1
• Time in Patent Office: 1,881 Days
• Field of Search: 375/229, 375/230, 375/232, 375/148
• US Class Current: 375/148
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10

Abstract

Apparatus comprising a pre-filter rake architecture with various features designed to, in at least some circumstances, to lessen the data processing burden associated with the architecture. In one embodiment, the pre-filter aspect can be disabled.

Claims

1. A method of ameliorating channel effects present in a signal received through a channel, the method comprising assessing the interference affecting the signal and processing the signal to ameliorate channel effects, if intra-cell interference dominates inter-cell interference in the signal, in a manner comprising filtering the signal through filter means to ameliorate channel dispersion in the signal and then processing the signal through Rake receiver means or, if intra-cell interference does not dominate inter-cell interference in the signal, in a manner comprising processing the signal through the Rake receiver means without prior amelioration of channel dispersion by the filter means.

2. The method according to claim 1, wherein the step of assessing the interference comprises calculating the ratio of, on the one hand, intracell interference and, on the other hand, intercell interference and noise.

3. A method of quantising soft decisions, the method comprising determining a quantisation step and using the step to quantise soft decisions obtained by demodulating symbols constituting a signal, wherein the size of the quantisation step is determined with regard to an amplitude distribution of the symbols,

wherein said determining step comprises characterising said distribution using a function of the average amplitude of and of the average power of symbols from the signal.

4. The method according to claim 3, wherein said function has the form λ

+√

{square root over (χ

−

λ

²)}, wherein λ

is the average amplitude and χ

is average constellation power.