Reducing collisions in a radio communications system
View Patent ↗A method and apparatus are provided that allows a predetermined training sequence to be selected from among different choices. According to one aspect of the present invention, the invention includes receiving a downlink broadcast burst from a base station, determining timing for sending an uplink burst, selecting a training sequence for the uplink burst; and transmitting the uplink burst using the selected training sequence.
1. A method comprising:
receiving at a receiving station a downlink broadcast burst from a base station;
determining timing for transmitting an uplink burst;
selecting a training sequence at the receiving station for the uplink burst by determining a digit from a number stored in the receiving station, the number being unique to each receiving station, and applying the determined digit to select from among a set of predetermined training sequences; and
transmitting the uplink burst from the receiving station using the selected training sequence.
2. The method of claim 1 wherein the stored number comprises the identification number of the receiving station.
3. The method of claim 1 wherein receiving a downlink broadcast burst comprises receiving an indication of a set predetermined training sequences for use in selecting a training sequence.
4. The method of claim 1 wherein determining timing comprises determining timing of a broadcast channel on which broadcast burst was received.
5. The method of claim 1 wherein determining timing comprises determining nominal timing relative to a frame of the broadcast burst.
6. The method of claim 1 wherein determining timing comprises determining timing on a broadcast channel on which the broadcast burst was received.
7. The training sequence of claim 1 wherein the training sequence training sequence comprises a repetition of a core sequence successively a specified number of times.
8. The training sequence of claim 7 wherein the core sequence has 12 symbols.
9. The training sequence of claim 7 wherein the core sequence has a normalized cross-correlation of about ⅓.
10. The training sequence of claim 7 wherein the core sequence has a normalized autocorrelation of about ⅓.
11. The training sequence of claim 7 wherein the absolute value of the mean of the core sequence is about zero.
12. A machine-readable medium having stored thereon data representing sequences of instructions which, when executed by a machine, cause the machine to perform operations comprising:
receiving at a receiving station a downlink broadcast burst from a base station;
determining timing for transmitting an uplink burst;
selectin a training sequence at the receiving station for the uplink burst by determining a digit from a number stored in the receiving station, the number being unique to each receiving station, and applying the determined digit to select from among a set of predetermined training sequences; and
transmitting the uplink burst from the receiving station using the selected training sequence.
13. The medium of claim 12 wherein the stored number comprises a sequence further comprising instructions for determining a digit from an identification number of the receiving station.
14. The medium of claim 12 wherein the instructions causing the machine to perform operations comprising receiving a downlink broadcast burst further comprise instructions for receiving an indication of a set of predetermined training sequences for use in selecting a training sequence.
15. An apparatus comprising:
a receiver to receive a downlink broadcast burst from a base station;
a processor to determine timing for sending an uplink burst, and to selecting a training sequence at the receiving station for the uplink burst by determining a digit from a number stored in the receiving station, the number being unique to each receiving station, and applying the determined digit to select from among a set of predetermined training sequences for the uplink burst; and
a transmitter to transmit the uplink burst using the selected training sequence.
16. The apparatus of claim 15 further comprising a register containing an identification number of the apparatus and wherein the processor selects by determining a digit from the identification number register.
17. The apparatus of claim 15 wherein the receiver receives a downlink broadcast burst including an indication of a set of predetermined training sequences for use in selecting a training sequence.
18. The method of claim 15 wherein determining timing comprises determining timing of a broadcast channel on which the broadcast burst was received.