Uplink transmitter in a random phase multiple access communication system
A method for communicating through a multiple access communication interface includes receiving a first signal from a first tag, where the first signal is spread using a predetermined pseudo-noise (PN) code, and further where the first signal includes first payload data. A second signal is received from a second tag. The second signal is spread using the predetermined PN code, and the second signal includes second payload data. The first payload data from the first signal is identified at least in part with a PN array despreader. The second payload data from the second signal is also identified at least in part with the PN array despreader.
1. A method for communicating information to an access point, the method comprising:
generating a data stream at a processor;
spreading the data stream with a common pseudo-noise (PN) code, wherein the common PN code is used by a plurality of tags in communication with the access point;
applying a frequency offset to the spread data stream based at least in part on a timing of the access point; and
transmitting the spread data stream with a randomly selected timing offset.
2. The method of claim 1 , wherein the common PN code comprises a gold code.
3. The method of claim 1 , further comprising receiving an acknowledgement, wherein the acknowledgement indicates that a transmission of the spread data stream is successful.
4. The method of claim 1 , further comprising re-transmitting the spread data stream with a second randomly selected timing offset if an acknowledgement is not received within a predetermined time period.
5. The method of claim 1 , wherein the data stream is spread with a spreading factor of 64, 128, 256, 512, 1024, 2048, 4096, or 8192.
6. The method of claim 1 , wherein the spread data stream is transmitted in a randomly selected sub-slot of a transmit slot.
7. The method of claim 1 , wherein the randomly selected timing offset is between zero and a spreading factor minus one.
8. A transmit apparatus for communicating information to an access point, the transmit apparatus comprising:
a pseudo-noise (PN) spreader configured to receive a data stream and spread the data stream with a common PN code, wherein the common PN code is used by a plurality of tags in communication with the access point;
a frequency control rotator in communication with the PN spreader and configured to apply a frequency offset to the spread data stream based at least in part on a timing of the access point;
a delay module in communication with the frequency control rotator and configured to generate a randomly selected timing offset for the spread data stream; and
a transmitter configured to transmit the spread data stream with the randomly selected timing offset.
9. The transmit apparatus of claim 8 , wherein the common PN code comprises a gold code.
10. The transmit apparatus of claim 8 , further comprising an encoder configured to encode the data stream.
11. The transmit apparatus of claim 8 , wherein the transmitter is further configured to re-transmit the spread data stream with a second randomly selected timing offset if an acknowledgement is not received within a predetermined time period.
12. The transmit apparatus of claim 8 , wherein the data stream is spread with a spreading factor of 64, 128, 256, 512, 1024, 2048, 4096, or 8192.
13. The transmit apparatus of claim 8 , wherein the transmitter is further configured to transmit the spread data stream in a randomly selected sub-slot of a transmit slot.
14. The transmit apparatus of claim 8 , wherein the randomly selected timing offset is between zero and a spreading factor minus one.
15. A tag for communicating information to an access point, wherein the tag comprises:
a transmit apparatus comprising
a pseudo-noise (PN) spreader configured to receive a data stream and spread the data stream with a common PN code, wherein the common PN code is used by a plurality of tags in communication with the access point;
a frequency control rotator in communication with the PN spreader and configured to apply a frequency offset to the spread data stream based at least in part on a timing of the access point;
a delay module in communication with the frequency control rotator and configured to generate a randomly selected timing offset for the spread data stream; and
a transmitter configured to transmit the spread data stream with the randomly selected timing offset;
a processor in communication with the transmit apparatus, wherein the processor is configured to execute operations performed by the transmit apparatus; and
a receiver in communication with the processor.
16. The tag of claim 15 , wherein the receiver is configured to receive an acknowledgement, and further wherein the acknowledgement indicates that a transmission of the spread data stream is successful.
17. The tag of claim 16 , wherein the transmitter is further configured to re-transmit the spread data stream with a second randomly selected timing offset if the acknowledgement is not received within a predetermined time period.
18. The tag of claim 15 , wherein the data stream is spread with a spreading factor of 64, 128, 256, 512, 1024, 2048, 4096, or 8192.
19. The tag of claim 15 , wherein the transmitter is further configured to transmit the spread data stream in a randomly selected sub-slot of a transmit slot.
20. The tag of claim 15 , wherein the randomly selected timing offset is between zero and a spreading factor minus one.