06310869 is referenced by 28 patents and cites 13 patents.

Several methods and corresponding apparatus reduce peak to average power in signals transmitted in a wireless communications system, particularly with respect to pilot symbols transmitted from a base station to several user stations. A large peak to average amplitude of inserted pilot symbols has been found to result from a common sign chip position that exists in orthogonal codes, such as Walsh codes. In a first embodiment, the Walsh codes are multiplied by a random value of ±1. Under a second embodiment, the common sign chip position is eliminated in each Walsh code. The user station then inserts the missing chip position to regain orthogonality. In a third embodiment, the base station transmits pilot symbols, on a separate pilot channel, in only symbol positions that user stations expect to find pilot symbols. Under a fourth embodiment, each Walsh code is randomly shifted.

Title
Method and apparatus for reducing amplitude variations and interference in communication signals, such as in wireless communication signals employing inserted pilot symbols
Application Number
9/144402
Publication Number
6310869 (B1)
Application Date
August 31, 1998
Publication Date
October 30, 2001
Inventor
Leonid Razoumov
San Diego
CA, US
Daisuke Terasawa
San Diego
CA, US
Jack Holtzman
San Diego
CA, US
Agent
Pavel Kalousek
US
Kent D Baker
US
Philip Wadsworth
US
Assignee
Qualcomm Incorporated
CA, US
IPC
H04J 13/00
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