Advanced Signal Processors for Interference Cancellation in Baseband Receivers

• US 20140341323A1
• Filed: 12/16/2013
• Published: 11/20/2014
• Est. Priority Date: 09/20/2002
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC
• Original Assignee: III Holdings 1, LLC
• Inventors: McCloud, Michael L., Nagarajan, Vijay
• Granted Patent: US 9,172,411 B2
• Time in Patent Office: Days
• US Class Current: 375/346
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04J 13/0003 Code application, i.e. aspects relating to how codes are applied to form multiplexed channels
• CPC Class Codes: H04J 13/20 having an orthogonal variable spreading factor [OVSF]
• CPC Class Codes: H04J 2011/0006 with CDM/CDMA
• CPC Class Codes: H04W 24/06 Testing, supervising or monitoring using simulated traffic

Abstract

An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.

Claims

1. A method for cancelling interference from a received baseband signal in a CDMA system, comprising:

generating at least one composite interference vector (CIV) by combining estimates from interfering subchannels,

generating a soft-cancellation operator, and

performing a soft cancellation of the received baseband signal to output an interference-cancelled signal.