Method and System for Adaptive Orthogonal Frequency Division Multiplexing Using Precoded Cyclic Prefix

• US 20090279626A1
• Filed: 05/07/2009
• Published: 11/12/2009
• Est. Priority Date: 05/07/2008
• Status: Active Grant

• Current Assignee: Xianbin Wang
• Original Assignee: Xianbin Wang
• Inventors: WANG, XIANBIN
• Granted Patent: US 8,565,063 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• 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 communication signal communication on a wireless or wireline network comprising the following steps for transmission of an adaptive communication signal:

a. detecting the communication environment or determining communication requirements, for communication on the wireless or wireline network;

b. determining system parameter information for adaptive OFDM based on the communication environment or communication requirements;

c. encoding the system parameter information into at least one precoded cyclic prefix (PCP) sequence;

d. generating a OFDM symbol transmission by combining at least one PCP, and an adaptive Orthogonal Frequency Division Multiplexing (OFDM) symbol, using the system parameters encoded in the corresponding PCP;

e. transmitting the signal from at least one OFDM transmitter to at least one OFDM receiver;

f. demodulating the at least one PCP; and

g. demodulating the OFDM signal using the system parameters recovered in step (fi.

2. The method of claim 1 wherein the system parameter information encoded to the PCP is applied by operation of an Orthogonal Frequency Division Multiplexing (OFDM) wireless or wireline communication platform.

3. The method of claim 2 further comprising the step of the OFDM transmitter and the OFDM receiver adapting a communication link therebetween using the PCP.

4. The method of claim 3 wherein the OFDM transmitter includes or is linked to 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 OFDM symbols using variable system parameters including a data carrying multicarrier modulated signal section and the PCP.

5. The method of claim 4 wherein the data carrying multicarrier modulated signal is generated using the inverse Discrete Fourier Transform (IDFT), with its size controlled by the SSCU.

6. The method claimed in claim 4 wherein the PCP comprises at least one signal sequence, representing the OFDM wireless or wireline communication platform, and controlling information sent to the OFDM receiver.

7. The method of claim 6 wherein the PCP for each OFDM symbol is changed from one OFDM symbol to another, depending on the controlling information from the SSCU.

8. The method of claim 6 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 the data information to be transmitted wherein the transmitter includes one additional PCP and a guard time which is no less than one PCP duration before new PCP and OFDM symbol with a new system parameter can be used and the transmitted signal can adapt its bandwidth by changing the size of the inverse Fourier transform.

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

10. The method of claim 4 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 signal parameter element is modulated by the controlling information from SSCU.

11. The method of claim 4 wherein the at least one signal sequence is precoded by transmitter information and system parameters, including one or more of modulation and coding schemes, transmission bandwidth, and carrier frequency.

12. The method of claim 1 comprising the additional step of determining the controlling information from parameters of the multimedia communication data stream from an associated binary information source.

13. 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.

15. The method of claim 1 comprising adaptive communication signal receiving, such adaptive communication signal receiving including the further step of canceling 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, using the identified PCP and the estimated channel impulse response.

16. The method claimed in claim 10 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 of 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 cyclic prefix, and the spectrum of the PCP sequence are computed from zero-padded signal data part 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 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 pilot are computed from pilot signal with duration of N+Ncp samples, where all the data carrying subcarriers are set to zero.

14. The method of wherein the method comprises the additional step of a frame synchronization method using the correlation between the received signal and the identification element of the PCP sequence.

17. A method for adaptive communication signal communication on a wireless or wireline network comprising the following steps for transmission of an adaptive communication signal:

a. generating an Orthogonal Frequency Division Multiplexing (OFDM) transmission by combining at least one precoded cyclic prefix (PCP) and an adaptive OFDM symbol using system parameters encoded in the corresponding PCP;

b. transmitting the signal from at least one OFDM transmitter to at least one OFDM receiver;

c. demodulating the at least one PCP; and

d. demodulating the OFDM signal using the system parameters recovered from step (c).

18. An adaptive Orthogonal Frequency Division Multiplexing (OFDM) system for providing a wireless or wireline network or a wireless or wireline communication platform, the OFDM system comprising or being linked to at least one OFMD receiver and at least one OFDM transmitter, wherein the OFDM receiver and OFDM transmitter are operable to adapt their communication link based on variable transmission parameters using a precoded cyclic prefix (PCP).

19. The system of claim 18, PCP can represent one or more of the following transmission parameters:

spectrum sensing, sharing and bandwidth control, location information, transmission parameters, transmission power control information, or other receiver and transmitter interaction information.

20. A wireless or wireline device comprising an OFDM transmitter and optionally an OFDM receiver, the wireless or wireline device being connectable to a wireless network for wireless or wireline communications, wherein the OFDM transmitter and the OFDM receiver are operable to facilitate adaptation of wireless or wireline communications to address variable transmission parameters in the wireless or wireline network, using a precoded cyclic prefix (PCP) in the wireless communications.

21. A wireless or wireline communication management server comprising one or more network servers connectable to a wireless or wireline network, wherein a plurality of wireless or wireline devices are connectable to the wireless or wireline network, and the one or more network servers are operable to manage wireless communications between the wireless devices on the wireless or wireline network, wherein the one or more network servers include or are linked to a computer program operable to enable the one or more network servers to:

a. enable processing of one or more wireless or wireline transmissions that include at least on precoded cyclic prefix (PCP) using an adaptive Orthogonal Frequency Division Multiplexing (OFDM) system, said PCP being based on variable signal parameters associated with the wireless or wireline device sending the wireless transmission; and

b. adapting one or more wireless network parameters based on the variable signal parameters based on the wireless or wireline transmissions including the PCP.

22. A wireless or wireline device computer program comprising computer instructions which when made available to a wireless or wireline device connectable to a wireless or wireline network are operable on the wireless or wireline device to enable (1) the generation of a wireless or wireline transmission comprising at least one PCP sequence based on variable signal:

parameters associated with the wireless or wireline device, (2) demodulation of the PCP.