Signal acquisition in a wireless communication system by transmitting repeated access probes from a terminal to a hub
First Claim
1. A method for signal acquisition in a wireless communication system between a terminal and a hub comprising the steps of:
- transmitting a system time message from said hub at a system message transmit time;
receiving said system time message at said terminal at a system message receive time following said system message transmit time by an unknown amount of time;
determining a first access probe transmit time for transmitting a first access probe from said terminal;
transmitting said first access probe from said terminal at said first access probe transmit time; and
sequentially transmitting a plurality of additional access probes each offset from one another by an amount of time equal to said time period adjusted by a delta time interval, wherein said delta time interval is set to a duration shorter than the duration of any one of a set of predetermined sequential search windows employed by said hub, said search windows of substantially equal duration and offset from one another by a set time period.
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Accused Products
Abstract
A novel and improved method and apparatus for signal acquisition in a wireless telecommunication system having large transmission delay uncertainty is described. A terminal first acquires the forward link signal from a hub and extracts timing information from that forward link signal. Using the timing information the terminal estimates the time at which a next search window takes place during an access slot, and the time and pseudorandom code state necessary to transmit an access probe so as to arrive at during the search window assuming the terminal is located a maximum distance from the hub. The terminal proceeds to transmit additional access probes at times occurring one access slot period plus a delta time interval after the previous transmission. The delta time interval has a duration less than that of a search window associated with each access slot. Each access probe is processed with various transmission codes the states of which are incremented by an access slot period for each access probe transmitted.
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Citations
21 Claims
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1. A method for signal acquisition in a wireless communication system between a terminal and a hub comprising the steps of:
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transmitting a system time message from said hub at a system message transmit time; receiving said system time message at said terminal at a system message receive time following said system message transmit time by an unknown amount of time; determining a first access probe transmit time for transmitting a first access probe from said terminal; transmitting said first access probe from said terminal at said first access probe transmit time; and sequentially transmitting a plurality of additional access probes each offset from one another by an amount of time equal to said time period adjusted by a delta time interval, wherein said delta time interval is set to a duration shorter than the duration of any one of a set of predetermined sequential search windows employed by said hub, said search windows of substantially equal duration and offset from one another by a set time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A wireless telecommunications system comprising:
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a hub for transmitting a system time message from said hub at a system message transmit time and for searching for access probes during a set of predetermined sequential search windows of substantially equal duration and offset from one another by a set time period; and a terminal for receiving said system time message at a system message receive time following said system message transmit time by an unknown amount of time, for determining a first access probe transmit time for transmitting a first access probe from said terminal, for transmitting said first access probe from said terminal at said first access probe transmit time, and for sequentially transmitting a plurality of additional access probes each offset from one another by an amount of time equal to said time period adjusted by a delta time interval, wherein said delta time interval is set to a duration shorter than the duration of said search windows. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for signal acquisition in a wireless communication system between a terminal and a hub comprising:
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means for transmitting a system time message from said hub at a system message transmit time; means for receiving said system time message at said terminal at a system message receive time following said system message transmit time by an unknown amount of time; means for determining a first access probe transmit time for transmitting a first access probe from said terminal; means for transmitting said first access probe from said terminal at said first access probe transmit time; and means for sequentially transmitting a plurality of additional access probes each offset from one another by an amount of time equal to said time period adjusted by a delta time interval, wherein said delta time interval is set to a duration shorter than the duration of any one of a set of predetermined sequential search windows employed by said hub, said search windows of substantially equal duration and offset from one another by a set time period. - View Dependent Claims (20)
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21. A method for establishing wireless communication with a hub located an unknown transmission distance away, said method comprising the steps of:
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(a) receiving a system time message delayed by an amount no greater than a maximum delay; (b) adjusting an internal time to said system time plus one predetermined maximum round trip delay; (c) transmitting an access probe at a next time slot according to said internal system time; (d) adjusting said internal time by a delta time interval that is less than the duration of any one of a set of predetermined sequential search windows employed by said hub, said search windows of substantially equal duration and offset from one another by a set time period; and (e) transmitting a second access probe at a next available time slot offset by said time period and calculated according to said internal system time.
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Specification