Methods and apparatus for supporting uplinks with remote base stations
First Claim
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;
coding information in a first access probe signal that identifies a first superslot index;
transmitting the first access probe signal that identifies the first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index;
monitoring to determine if a response to the first access probe signal was received from the base station;
if it is determined that the response to the first access probe signal was received,performing a transmission timing adjustment as a function of information included in the response; and
if it is determined that the response to the first access probe signal was not received,coding information in a second access probe signal that identifies a second superslot index, andtransmitting the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset.
3 Assignments
0 Petitions
Accused Products
Abstract
A wireless terminal using OFDM signaling supporting both terrestrial and satellite base station connectivity operates using conventional access probe signaling in a first mode of operation to establish a timing synchronized wireless link with a terrestrial base station. In a second mode of operation, used to establish a timing synchronized wireless link with a satellite base station, a slightly modified access protocol is employed. The round trip signaling time and timing ambiguity between a wireless terminal and a satellite base station is substantially greater than with a terrestrial base station. The modified access protocol uses coding of access probe signals to uniquely identify a superslot index within a beaconslot. The modified protocol uses multiple access probes with different timing offsets to further resolve timing ambiguity and allows the satellite base station access monitoring interval to remain small in duration. Terrestrial base station location/connection information is used to estimate initial timing.
38 Citations
37 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; coding information in a first access probe signal that identifies a first superslot index; transmitting the first access probe signal that identifies the first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index; monitoring to determine if a response to the first access probe signal was received from the base station; if it is determined that the response to the first access probe signal was received, performing a transmission timing adjustment as a function of information included in the response; and if it is determined that the response to the first access probe signal was not received, coding information in a second access probe signal that identifies a second superslot index, and transmitting the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. 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 communications device comprising:
-
a receiver for receiving at least one beacon signal; a received signal processing module for receiving signals including at least one received beacon signal, the processing module to determine a downlink timing reference point from the at least one received beacon signal, superslots occurring within a beacon slot having a predetermined relationship to the determined downlink timing reference point; a coding module for coding information in a first access probe signal that identifies a first superslot index; a transmitter for transmitting the first access probe signal that identifies the first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index; if a monitoring module determines a response to the first access probe signal was received from the base station, then a timing correction module, responsive to said monitoring module, performs a transmission timing adjustment as a function of information included in the response; and if the monitoring module determines the response to the first access probe signal was not received from the base station, then the coding module codes information in a second access probe signal that identifies a second superslot index, and the transmitter transmits the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. 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 communications device comprising:
a processor configured to; control the communications device to receive at least one beacon signal; control the communications device to process 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; control the communications device to encode information in a first access probe signal that identifies a first superslot index; control the communications device to transmit the first access probe signal that identifies the first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index; control the communications device to monitor to determine if a response to the first access probe signal was received from the base station; and if it is determined that the response to the first access probe signal was received, control the communications device to perform a transmission timing adjustment as a function of information included in said response;
orif it is determined that the response to the first access probe signal was not received, control the communications device to encode information in a second access probe signal that identifies a second superslot index, and control the communications device to transmit the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset.
-
34. A computer readable medium embodying computer executable instructions for controlling a communications device 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 computer readable medium comprising:
-
instructions for causing the communications device to receive at least one beacon signal; instructions for causing the communications device to process 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; instructions for causing the communications device to encode information in a first access probe signal that identifies a first superslot index; instructions for causing the communications device to transmit the first access probe signal that identifies the first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index; instructions for causing the communications device to monitor to determine if a response to the first access probe signal was received from the base station; instructions for causing the communications device to perform a transmission timing adjustment as a function of information included in the response if it is determined that a response was received; and instructions for causing the communications device to encode information in a second access probe signal that identifies a second superslot index, and transmit the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset, if it is determined that the response to the first access probe signal was not received. - View Dependent Claims (35)
-
-
36. 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 communications device comprising:
-
receiver means for receiving at least one beacon signal; received signal processing means for processing the received signals including received beacon signals, to determine a downlink timing reference point from at least one received beacon signal, superslots occurring within a beacon slot having a predetermined relationship to the determined downlink timing reference point; coding means for coding information in a first access probe signal that identifies a first superslot index; transmitter means for transmitting the first access probe signal that identifies a first superslot index, the first access probe signal being transmitted at a first timing offset relative to a start of a first superslot having the first superslot index; if monitoring means determines a response to the first access probe signal was received from the base station, then timing correction means, responsive to said monitoring means, performs a transmission timing adjustment as a function of information included in the response; and if the monitoring means determines the response to the first access probe signal was not received from the base station, then the coding means codes information in a second access probe signal that identifies a second superslot index, and the transmitter means transmits the second access probe signal that identifies the second superslot index at a second timing offset relative to a start of a second superslot having the second superslot index, the second timing offset being different from the first timing offset. - View Dependent Claims (37)
-
Specification