Application of asynchronous coded multiple access (ACMA) in a system employing orthogonal frequency division multiplexing (OFDM)

1. A method for transmitting a random-access Radio Frequency (RF) signal by applying Asynchronous Coded Multiple Access (ACMA) in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the method comprising:

providing a reference clock defining symbol-start instants;

encoding an information stream as OFDM symbols using a low rate forward error correction (FEC) coding suitable for successive interference cancellation (SIC) to form a payload;

generating a burst, comprising symbols, by performing an Inverse Fast Fourier Transform on a Unique Word (UW) multiplexed with the payload; and

synchronizing a transmission of each of the symbols of the burst with consecutive symbol-start instants,

wherein

the UW comprises a plurality of Zadoff-Chu (ZC) like sequences disposed in a subset of consecutive symbol-start instants of the burst.

2. The method of claim 1 , wherein each of the symbols comprises T tones, each of the plurality of ZC-like sequences is based on a prime number less than or equal to T, and each of the plurality of ZC-like sequences is cyclically extended to T sequences.

3. The method of claim 1 , wherein the UW is multiplexed with the payload by disposing the UW before the payload.

4. The method of claim 1 , wherein the burst further comprises a Channel State Estimation (CSE) word multiplexed with the payload, the CSE comprise a ZC-like sequence, and the UW and the CSE word are used for performing a channel state estimation.

5. The method of claim 1 , further comprising scrambling the payload.

6. The method of claim 1 , wherein the reference clock further defines frames, each of the frames comprises a subset of symbol-start instants, the burst is disposed in one of the frames, and a count of the symbols in the burst is less than or equal to a count of the subset of symbol-start instants of a respective frame of the frames.

7. A user equipment (UE) to communicate a random-access Radio Frequency (RF) signal by applying Asynchronous Coded Multiple Access (ACMA) in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the UE comprising:

a reference clock defining symbol-start instants;

an encoder to encode an information stream as OFDM symbols using a low rate forward error correction (FEC) coding suitable for successive interference cancellation (SIC) to form a payload; and

an Inverse Fast Fourier Transform block to generate a burst, comprising symbols, by transforming a Unique Word (UW) multiplexed with the payload; and

wherein

the UW comprises a plurality of Zadoff-Chu (ZC) like sequences disposed in a subset of consecutive symbol-start instants of the burst, and

a transmission of each of the symbols of the burst is synchronized with consecutive symbol-start instants of the reference clock.

8. The UE of claim 7 , wherein each of the symbols comprises T tones, each of the plurality of ZC-like sequences is based on a prime number less than or equal to T, and each of the plurality of ZC-like sequences is cyclically extended to T sequences.

9. The UE of claim 7 , wherein the UW is multiplexed with the payload by disposing the UW before the payload.

10. The UE of claim 7 , wherein the burst further comprises a Channel State Estimation (CSE) word multiplexed with the payload, the CSE comprise a ZC-like sequence, and the UW and the CSE word are used for performing a channel state estimation.

11. The UE of claim 7 , further comprising a scrambler to scramble the payload.

12. The UE of claim 7 , wherein the reference clock further defines frames, each of the frames comprises a subset of symbol-start instants, the burst is disposed in one of the frames, and a count of the symbols in the burst is less than or equal to a count of the subset of symbol-start instants of a respective frame of the frames.

13. The UE of claim 7 , further comprising an antenna to communicate the burst to a receiver.

14. A method for detecting a random-access burst arrival in a communication system applying Asynchronous Coded Multiple Access (ACMA) employing Orthogonal Frequency Division Multiplexing (OFDM), the method comprising:

providing a reference clock defining symbol-start instants;

receiving bursts comprising symbols comprising multiplexed Zadoff-Chu (ZC) like sequences and a payload;

searching for ZC-like sequences at each of the symbol-start instants in the bursts; and

detecting a burst arrival when symbols disposed at a subset of consecutive symbol-start instants match a unique word (UW),

wherein

the symbols are Orthogonal Frequency Division Multiplexing (OFDM) symbols disposed in consecutive symbol-start instants and encoded using a low rate forward error correction (FEC) coding suitable for successive interference cancellation (SIC),

at least two of the bursts are at least partially concurrent,

the UW comprises a plurality of cyclically shifted ZC-like sequences, and

each of the bursts is modulated at a common frequency over a common frequency band with a common polarization.

15. The method of claim 14 , wherein the plurality of cyclically shifted ZC-like sequences are coherently combinable.

16. The method of claim 14 , wherein the UW is multiplexed with the payload by disposing the UW before the payload.

17. The method of claim 14 , wherein each of the bursts further comprises a Channel State Estimation (CSE) word multiplexed with the payload, the CSE comprise a ZC-like sequence, and the UW and the CSE word are used for performing a channel state estimation.

18. The method of claim 14 , further comprising descrambling the payload of at least one of the bursts.

19. The method of claim 14 , wherein the reference clock further defines frames, each of the frames comprises a subset of symbol-start instants, one of the bursts is disposed in one of the frames, and a count of the symbols in the one of the bursts is less than or equal to a count of the subset of symbol-start instants of a respective frame of the frames.

20. A base station to detect a random-access burst arrival in a communication system applying Asynchronous Coded Multiple Access (ACMA) employing Orthogonal Frequency Division Multiplexing (OFDM), the base station comprising:

a reference clock defining symbol-start instants;

a receiver to receive bursts comprising symbols comprising multiplexed Zadoff-Chu (ZC) like sequences and a payload; and

a burst detector to search for ZC-like sequences at each of the symbol-start instants in the bursts and to detect a burst arrival when symbols disposed at a subset of consecutive symbol-start instants match a unique word (UW),

wherein

the symbols are Orthogonal Frequency Division Multiplexing (OFDM) symbols disposed in consecutive symbol-start instants and encoded using a low rate forward error correction (FEC) coding suitable for successive interference cancellation (SIC),

at least two of the bursts are at least partially concurrent,

the UW comprises a plurality of cyclically shifted ZC-like sequences, and

each of the bursts is modulated at a common frequency over a common frequency band with a common polarization.

21. The base station of claim 20 , wherein the UW is multiplexed with the payload by disposing the UW before the payload.

22. The base station of claim 20 , wherein each of the bursts further comprises a Channel State Estimation (CSE) word multiplexed with the payload, the CSE comprise a ZC-like sequence, and the UW and the CSE word are used for performing a channel state estimation.

23. The base station of claim 20 , further comprising a descrambler to descramble the payload of at least one of the bursts.

24. The base station of claim 20 , wherein the reference clock further defines frames, each of the frames comprises a subset of symbol-start instants, one of the bursts is disposed in one of the frames, and a count of the symbols in the one of the bursts is less than or equal to a count of the subset of symbol-start instants of a respective frame of the frames.

25. The base station of claim 20 , further comprising an antenna to receive the bursts from a plurality of transmitters.