| US 7,574,224 B2 | ||
| Methods and apparatus for performing timing synchronization with base stations | ||
| Frank A. Lane, Asbury, N.J. (US); Rajiv Larola, Basking Ridge, N.J. (US); and Junyi Li, Bedminster, N.J. (US) | ||
| Assigned to QUALCOMM Incorporated, San Diego, Calif. (US) | ||
| Filed on Jul. 18, 2005, as Appl. No. 11/184,735. | ||
| Claims priority of provisional application 60/689910, filed on Jun. 13, 2005. | ||
| Prior Publication US 2006/0281476 A1, Dec. 14, 2006 | ||
| Int. Cl. H04B 7/00 (2006.01) | ||
| U.S. Cl. 455—502 [455/13.2; 455/208; 370/324; 370/350; 370/509; 370/510; 370/512] | 20 Claims |
| 1. A method of operating a communications device for use in a communications system where beacon time slots occur on a periodic
basis, a beacon signal being transmitted by a base station during each beacon time slot according to a periodic downlink timing
structure, said downlink timing structure including a plurality of superslots within each beacon slot, the individual superslots
within a beacon slot being identifiable through the use of a superslot index, each superslot including a plurality of symbol
transmission time periods, the method comprising:
receiving at least one beacon signal;
processing the received beacon signal to determine a downlink timing reference point, superslots occurring within a beacon
slot having a predetermined relationship to the determined downlink timing reference point;
transmitting a first access probe at a time corresponding to a first timing offset relative to the start of a super slot in
a beacon slot;
transmitting a second access probe at a time corresponding to a second timing offset relative to the start of a super slot,
said second access probe being transmitted at a point in time, which is less than the longer of i) twice the time required
for a transmitted signal to travel from the communications device to the base station and ii) the duration of a superslot,
from the point in time at which the first access probe was transmitted;
monitoring to determine if a response to one of the transmitted access probes was received from the base station; and
if it is determined that a response was received from the base station, performing a transmission timing adjustment as a function
of information included in said response.
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