Qualcomm Incorporated

Gordon Skinner, Deceased

Ephraim Zehavi

Brian K Harms

By Margo Boodakian, Executrix

A system and method for rapidly acquiring timing of an access transmission that uses an access probe that is transmitted in stages. A first stage of the access probe is spread with a short pseudonoise (PN) code pair. A second stage of the access probe is spread with both the short PN code pair and a long PN code. Transmitting the access probe in stages reduces the number of hypotheses, and hence the time, required by a receiver attempting to acquire the access probe.

Rapid signal acquisition and synchronization for access transmissions

A technique for using energy received by subscriber units over multiple orthogonal channels within a spread spectrum communication system to acquire signal timing by controlling signal amplitude integration intervals used in detecting such timing. Received signals are despread and respective amplitudes integrated over periods that are divisible by factors of 2 into the length of Walsh functions used to generate orthogonal signal channels. Non-coherent combinations of the results of this integration are subsequently formed over periods that commence and terminate on Walsh function boundaries, and used to determine when a correct time offset has been selected for despreading signals. Additional advantages are realized by assigning signals that consistently provide a higher energy content such as paging, synchronization, and most frequently assigned traffic channels to specific orthogonal channels within the communication system. In exemplary embodiments, Walsh functions of length 128 are used as channelizing codes and a pilot signal is assigned to channel 0. This results in traffic channels or paging and synchronization functions being assigned to channel 64 when the integration periods are 64 chips long, and to channels 32, 64, and 96 when the periods are 32 chips long. In this manner, additional energy is available during the integration process for use in determining when correct signal acquisition timing offsets have been selected, without the use of additional hardware.

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Gordon Skinner, Deceased