Method and system for adaptive orthogonal frequency division multiplexing using precoded cyclic prefix

• US 8,565,063 B2
• Filed: 05/07/2009
• Issued: 10/22/2013
• Est. Priority Date: 05/07/2008
• Status: Active Grant

• Current Assignee: Xianbin Wang
• Original Assignee: Xianbin Wang
• Inventors: Wang, Xianbin
• Primary Examiner(s): Vu, Huy D
• Assistant Examiner(s): Baig, Adnan
• Application Number:
  US12/437,358
• Publication Number:
  US 20090279626A1
• Time in Patent Office: 1,629 Days
• Field of Search: 370/208, 370/254, 370/332
• US Class Current: 370/208
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2605 Symbol extensions, e.g. Zero Tail, Unique Word [UW]
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: Y02D 30/00 Reducing energy consumption in communication networks

Abstract

A method for adaptive signal communication on a wireless or wireline network is disclosed including detecting the communication environment or determining the communication requirements, for communication on the wireless or wireline network. The method may include determining system parameter information for adaptive Orthogonal Frequency Division Multiplexing (OFDM) based on the communication environment or communication requirements and encoding the system parameter information into at least one precoded cyclic prefix (PCP) sequence. The method further provides for generating an OFDM symbol transmission by combining at least one PCP, and an adaptive OFDM symbol, using the system parameters, then transmitting the signal from at least one OFDM transmitter to at least one OFDM receiver followed by demodulating the at least one PCP, and demodulate the OFDM signal using the system parameters recovered. A related OFDM system for implementing the method for a wireless or wireline network or platform is disclosed as are wireless or wireline devices operable with this method.

Claims

1. A method for adaptive signal communication on a wireless or wireline network based on transmitter-receiver adaptation and interaction comprising the following steps for transmission and reception of an adaptive communication signal:

at a transmitter;

(a) detecting the communication environment and determining communication requirements by a common interface device from at least one local information source and controlling information received by the local receiver from a remote transmitter, for combined communication supporting at least one data stream on the wireless or wireline network;

(b) determining system transmission parameter information for adaptive Orthogonal Frequency Division Multiplexing (OFDM) transmission based on the communication environment or communication requirements in (a);

(c) dynamically encoding a binary sequence to represent a transmission scheme associated with the system transmission parameter information in (b);

(d) generating complex precoded cyclic prefix (PCP) providing an identification element and a system transmission parameter element based on the selected binary sequence in (c);

(e) generating a PCP-OFDM symbol transmission by combining in a communication signal (i) the at least one encoded PCP sequence, and (ii) an adaptive OFDM symbol without introducing any repetition of the OFDM symbol itself, wherein the adaptive OFDM symbol is generated with the data to be transmitted and the system transmission parameters encoded in the encoded PCP, thereby enabling adaptive transmission of the data based on the system parameters affecting the transmission;

(f) transmitting the communication signal from at least one OFDM transmitter to at least one OFDM receiver; and

at a receiver;

(g) receiving the communication signal and demodulating the at least one PCP to retrieve the system parameter information encoded into the PCP and estimating communication channel;

(h) demodulating the OFDM symbol and dividing the recovered combined data stream into original multiple form using the identification and system parameters recovered in step (g), after cancelling the interference from PCP to data-carrying OFDM signal using recovered PCP and channel in (g) and equalizing the received signal; and

(i) communicating controlling information to the local transmitter;

wherein the binary sequence includes a pseudo random sequence comprising one of an m-sequence, a Gold sequence or a Kasami sequence, and the interactive operation of an OFDM transmitter or receiver is enabled by the system transmission parameter information encoded into the PCP, the identification element of the PCP being a wireless or wireline communication transmitter identification.

2. The method of claim 1 for PCP enabled transmitter-receiver interaction, and the method further comprises the step of the OFDM transmitter and the OFDM receiver adapting a communication link therebetween using the PCP.

3. The method of claim 2 wherein the OFDM transmitter includes or is linked to a common interface device, receiver controlling information, a spectrum sensing and controlling unit (SSCU), and at least one OFDM signal generator is operable to generate one or more OFDM symbols, comprising the further step of the OFDM signal generator generating one or more adaptive OFDM symbols using variable system transmission parameters including a data carrying multicarrier modulated signal section and the PCP.

4. The method of claim 3 wherein the data carrying multicarrier modulated communication signal is generated using the Inverse Fast Fourier Transform (IFFT), with its size, bandwidth, modulation scheme, transmission power and carrier frequency controlled by the SSCU.

5. The method claimed in claim 3 wherein the PCP comprises at least one signal sequence, representing system transmission parameters of the OFDM wireless or wireline communication platform, and controlling information sent to at least one OFDM receiver.

6. The method of claim 5 wherein the PCP for each OFDM symbol is changed from one OFDM symbol to another, encoded from at least one binary sequence representing the controlling information from the SSCU.

7. The method of claim 5 wherein the PCP is combined with one OFDM symbol generated by the system parameter carried by the PCP depending on the controlling information from the SSCU, and with instruction identified for transmission, said PCP being at least one pseudo random sequence generated by a binary sequence representing the controlling information from SSCU, the transmitter further including one additional identical PCP and a guard time before new PCP and OFDM symbol with new system parameters can be used, wherein a series of new OFDM symbols are generated using the new system transmission parameters encoded into the new PCP, and the transmitted signal can adapt its bandwidth by changing the size of the inverse Fourier transform.

8. The method of claim 5 wherein the at least one PCP signal sequence is a complex Kasami sequence.

9. The method of claim 5 comprising the further steps of:

(a) generating an identification element of the sequence which represents identification of the transmitter and remains unchanged; and

(b) a system transmission parameter element is modulated by a binary sequence representing the controlling information from SSCU.

10. The method of claim 5 wherein the at least one signal sequence is precoded by transmitter instruction and system parameters, including one or more of modulation and coding schemes, transmission bandwidth, carrier frequency, instruction to receivers including combination schemes for multiple data streams, and transmitter identification.

11. The method of claim 1 comprising the additional step of determining the combined communication controlling information from parameters of at least one multimedia communication data stream from its associated binary information source.

12. The method of claim 1 comprising the further step of identifying an OFDM transmitter by differentiating received signals by their transmitting source using the identification element of the PCP sequence.

13. The method of claim 12 comprising the further step of initiating a frame synchronization method using the correlation between the received signal and the identification element of the PCP sequence.

14. The method of claim 1 comprising adaptive communication signal receiving, such adaptive communication signal receiving including the following steps:

i) cancelling or reducing interference so as to remove or reduce intra-carrier interference (ICI) or inter-block Interference (IBI) caused by the introduction of the PCP, reconstructed using the identified PCP and an estimated channel impulse response, or ii) equalizing one OFDM symbol and its PCP at the same time in a frequency domain and converting the equalized signal back to time domain using Fast Fourier Transform (FFT) and IFFT with size of the OFDM symbol and the PCP combined, and removing the equalized PCP from the time domain equalized signal and demodulating the OFDM signal using FFT with size of the OFDM symbol only.

15. The method claimed in claim 9 wherein the method comprises the additional step of a spectrum sensing technique for unsynchronized PCP-OFDM and conventional OFDM signals which are based on:

(a) the correlation between the spectrum from the identification element of PCP sequence and received PCP-OFDM signal, wherein the spectrum OFDM signal is computed from the signal segment with duration of N+Ncp samples, where N and Ncp are the duration of the OFDM symbol and precoded cyclic prefix, and the spectrum of the PCP sequence are computed from zero-padded PCP sequence with duration of N+Ncp samples, where all following N samples are set to zero; and

(b) the correlation of between the spectrum from the local in-band pilots reference and received conventional OFDM signal, wherein the spectrum OFDM signal is computed from the signal segment with duration of N+Ncp samples, where N and Ncp are the duration of the OFDM symbol and cyclic prefix, and the spectrum of the in-band pilot reference are computed from pilot only OFDM signal with duration of N+Ncp samples, where all the data carrying subcarriers are set to zero.

16. A system for adaptive signal communication on a wireless or wireline network based on transmitter-receiver adaptation and interaction, wherein the system is adapted to perform the following for transmission and reception of an adaptive communication signal:

at a transmitter;

(a) detect the communication environment and determine communication requirements by a common interface device from at least one local information source and control information received by the local receiver from a remote transmitter, for combined communication supporting at least one data stream on the wireless or wireline network;

(b) determine system transmission parameter information for adaptive Orthogonal Frequency Division Multiplexing (OFDM) transmission based on the communication environment or communication requirements in (a);

(c) dynamically encode a binary sequence to represent a transmission scheme associated with the system transmission parameter information in (b);

(d) generate a complex precoded cyclic prefix (PCP) providing an identification element and a system transmission parameter element based on the selected binary sequence in (c);

(e) generate a PCP-OFDM symbol transmission by combining in a communication signal (i) the at least one encoded PCP sequence, and (ii) an adaptive OFDM symbol without introducing any repetition of the OFDM symbol itself, wherein the adaptive OFDM symbol is generated with the data to be transmitted and the system transmission parameters encoded in the encoded PCP, thereby enabling adaptive transmission of the data based on the system parameters affecting the transmission;

(f) transmit the communication signal from at least one OFDM transmitter to at least one OFDM receiver; and

at a receiver;

(g) receive the communication signal and demodulate the at least one PCP to retrieve the system parameter information encoded into the PCP and estimating communication channel;

(h) demodulate the OFDM symbol and divide the recovered combined data stream into original multiple form using the identification and system parameters recovered in (g), after cancelling the interference from PCP to data-carrying OFDM signal using the recovered PCP and channel in (g) and equalizing the received signal; and

(i) communicate controlling information to the local transmitter;

wherein the binary sequence includes a pseudo random sequence comprising one of an m-sequence, a Gold sequence or a Kasami sequence, and the interactive operation of an OFDM transmitter or receiver is enabled by the system transmission parameter information encoded into the PCP, the identification element of the PCP being a wireless or wireline communication transmitter identification.

17. A non-transitory computer readable media storing computer code that when loaded onto transmitter and receiver devices adapts the devices to perform a method for adaptive signal communication on a wireless or wireline network based on transmitter-receiver adaptation and interaction, the non-transitory computer readable media comprising:

(a) code for detecting, at a transmitter, the communication environment and determining communication requirements by a common interface device from at least one local information source and controlling information received by the local receiver from a remote transmitter, for combined communication supporting at least one data stream on the wireless or wireline network;

(b) code for determining, at the transmitter, system transmission parameter information for adaptive Orthogonal Frequency Division Multiplexing (OFDM) transmission based on the communication environment or communication requirements in (a);

(c) code for dynamically encoding, at the transmitter, a binary sequence to represent a transmission scheme associated with the system transmission parameter information in (b);

(d) code for generating, at the transmitter, a complex precoded cyclic prefix (PCP) providing an identification element and a system transmission parameter element based on the selected binary sequence in (c);

(e) code for generating, at the transmitter, a PCP-OFDM symbol transmission by combining in a communication signal (i) the at least one encoded PCP sequence, and (ii) an adaptive OFDM symbol without introducing any repetition of the OFDM symbol itself, wherein the adaptive OFDM symbol is generated with the data to be transmitted and the system transmission parameters encoded in the encoded PCP, thereby enabling adaptive transmission of the data based on the system parameters affecting the transmission;

(f) code for transmitting the communication signal from at least one OFDM transmitter to at least one OFDM receiver;

(g) code for receiving, at a receiver, the communication signal and demodulating the at least one PCP to retrieve the system parameter information encoded into the PCP and estimating communication channel;

(h) code for demodulating, at the receiver, the OFDM symbol and dividing the recovered combined data stream into original multiple form using the identification and system parameters recovered in (g), after cancelling the interference from PCP to data-carrying OFDM signal using recovered PCP and channel in (g) and equalizing the received signal; and

(i) code for communicating controlling information to the local transmitter;

wherein the binary sequence includes a pseudo random sequence comprising one of an m-sequence, a Gold sequence or a Kasami sequence, and the interactive operation of an OFDM transmitter or receiver is enabled by the system transmission parameter information encoded into the PCP, the identification element of the PCP being a wireless or wireline communication transmitter identification.