Abstract: Orthogonal transmit diversity is implemented by employing a data splitter (803) to subdivide channel information (801) into at least a first portion of bits (802) and a second portion of bits (804). Each portion is spread with its own Walsh code for eventual transmission to a mobile station via a predetermined carrier frequency. When the number of bits in the first and second portion (802, 804) are small, separate Walsh codes are used to maintain orthogonality. When the number of bits in the first and second portion (802, 804) are relatively large, a time-division multiplex transmission is used to maintain orthogonality. A controller (809) controls the subdivision of the channel information and also an interleaver (308) to further enhance the effects of the diversity transmission. Control information related to the subdivision is transmitted to the mobile station so the channel information can be accurately reconstructed prior to decoding.
Type:
Grant
Filed:
September 4, 1997
Date of Patent:
January 9, 2001
Assignee:
Motorola, Inc.
Inventors:
Michael D. Kotzin, Kamyar Rohani, Walter J. Rozanski, Jr.
Abstract: A cellular communication system (50) is offered wherein communicated signals are exchanged on an indexed uplink communication resource and a non-indexed downlink communication resource. The non-indexed downlink communication format allows communication units to identify proximate service providers without knowledge of the index algorithm. The indexed signal transmitted by a user communication unit improves noise immunity in a signal transceived on the uplink. Signal quality is improved on the downlink through the use of selectable diversity antennas (22 or 23).