Wireless communication system based on code spreading-orthogonal frequency division multiple access and smart antenna

• US 8,174,960 B2
• Filed: 10/08/2008
• Issued: 05/08/2012
• Est. Priority Date: 10/10/2007
• Status: Expired due to Fees

• Current Assignee: Beijing Xinwei Telecom Technology Company Limited (Beijing Xinwei Technology Group Co., Ltd.)
• Original Assignee: Beijing Xinwei Telecom Technology Company Limited (Beijing Xinwei Technology Group Co., Ltd.)
• Inventors: Xu, Guanghan, Li, Hang, Huang, Jun
• Primary Examiner(s): Pham, Brenda H
• Application Number:
  US12/682,441
• Publication Number:
  US 20100238846A1
• Time in Patent Office: 1,308 Days
• Field of Search: 370/208, 370/203, 370/276, 370/295, 370/319, 370/334, 370/344, 370/349
• US Class Current: 370/208
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 5/0019 in which one code is applied, as a temporal sequence, to all frequencies

Abstract

A time division duplex wireless communication system based on Code Spreading-Orthogonal Frequency Division Multiple Access (CS-OFDMA) and a smart antenna includes: an antenna array and multichannel transceiver, a space processor, a demodulator, an L2 processor and a modulator. The CS-OFDMA system provided by the present invention combines synchronous CDMA technique and OFDMA technique, overcomes the severe ISI caused by spectrum-spreading by the conventional CDMA system while transmitting wideband data, effectively counteracts frequency-selective fading and inter-cell interference, and is beneficial to reliable transmission of narrowband voice and wideband data and also beneficial to co-frequency networking.

Claims

1. A time division duplex wireless communication system based on Code Spreading-Orthogonal Frequency Division Multiple Access (CS-OFDMA) and smart antenna, comprising:

an antenna array and multichannel transceiver, configured to receive a first CS-OFDMA signal from a terminal and transmit a second CS-OFDMA signal to the terminal, wherein receiving time does not overlap with transmitting time;

a space processor, configured to estimate a space-frequency channel response of the terminal according to the first CS-OFDMA signal received by the antenna array and multichannel transceiver from the terminal;

a demodulator, configured to perform a symbol detection according to the space-frequency channel response estimated by the space processor;

an L2 processor, configured to process a symbol detected by the demodulator, allocate uplink and downlink channels to the terminal according to a channel allocation definition of the system, generate a message for the terminal and a modulator and transmit the message to the modulator;

the modulator, configured to modulate the message into the second CS-OFDMA signal according to the space-frequency channel response estimated by the space processor and the message from the L2 processor, and transmit the second CS-OFDMA signal to the antenna array and multichannel transceiver.

2. The wireless communication system according to claim 1, wherein the space-frequency channel response estimated by the space processor comprises a space eigenvector and a frequency-domain channel response of the terminal.

3. The wireless communication system according to claim 1, wherein the channel allocation definition comprises:

dividing one continuous bandwidth into multiple non-overlapping frequency bands, selecting, from each frequency band, at least one non-overlapping frequency point to form a channel allocation unit.

4. The wireless communication system according to claim 1, wherein the modulator is further configured to modulate a terminal channel reallocation message from the L2 processor to a downlink traffic channel which is currently allocated to the terminal.

5. The wireless communication system according to claim 1, wherein the space processor is further configured to obtain a space eigenvector of the terminal from a predetermined random access channel;

the demodulator is further configured to demodulate an access request message of the terminal from the predetermined random access channel;

the L2 processor is further configured to allocate a channel and generate an access response message for the terminal;

the modulator is further configured to modulate the access response message to a predetermined random access response channel and perform beam forming according to the space eigenvector.

6. The wireless communication system according to claim 1, wherein the space processor is further configured to obtain interference and noise information from an uplink time-frequency window;

the L2 processor is further configured to allocate a channel according to the interference and noise information.

7. The wireless communication system according to claim 1, wherein the demodulator is further configured to demodulate an uplink message which is transmitted by the terminal and contains interference and noise information received by the terminal;

the L2 processor is further configured to allocate a channel according to the interference and noise information.

8. The wireless communication system according to claim 1, wherein the demodulator is further configured to demodulate an uplink message which is transmitted by the terminal and contains interference, noise and transmitting power information received by the terminal;

the L2 processor is further configured to allocate a channel according to the interference, noise and transmitting power information.

9. The wireless communication system according to claim 1, wherein the space processor is further configured to detect an uplink ranging signal of the terminal as well as a delay and signal strength of the uplink ranging signal on a predetermined ranging channel;

the L2 processor is further configured to generate a ranging response message containing timing and power control information according to the delay and the signal strength of the uplink ranging signal.

10. The wireless communication system according to claim 9, wherein the ranging channel is located in a guard slot from a downlink to an uplink.

11. The wireless communication system according to claim 1, wherein the space processor is further configured to detect an uplink ranging signal of the terminal as well as a delay, signal strength and a space eigenvector of the uplink ranging signal on a predetermined ranging channel;

the L2 processor is further configured to generate a ranging response message containing timing and power control information according to the delay and the signal strength of the uplink ranging signal;

the modulator is further configured to perform beam forming according to the space eigenvector, and modulate the ranging response message to a predetermined ranging response channel.

12. The wireless communication system according to claim 1, wherein the space processor is further configured to obtain a space eigenvector and estimate statistics of interference and noise on a time-frequency window corresponding to a channel;

the demodulator is further configured to calculate weight of uplink beam forming for interference counteraction according to the space eigenvector and the estimated statistics of interference and noise.

13. The wireless communication system according to claim 6, wherein a location of the time-frequency window is determined by an index of a preamble of the wireless communication system.

14. The wireless communication system according to claim 1, wherein the space processor is further configured to estimate a delay of the terminal;

the L2 processor is further configured to generate a timing command message of the terminal according to the delay;

the modulator is further configured to modulate the timing command message to a terminal traffic channel.

15. The wireless communication system according to claim 1, wherein the space processor is further configured to obtain a space eigenvector of the terminal through a predetermined random access channel;

the demodulator is further configured to obtain a terminal access request message which contains interference and noise information received by the terminal from the predetermined random access channel by way of demodulation;

the L2 processor is further configured to allocate a channel according to the interference and noise information received by the terminal and generate a terminal access response message;

the modulator is further configured to modulate the terminal access response message to a predetermined access response channel, and perform beam forming according to the space eigenvector.

16. The wireless communication system according to claim 12, wherein a location of the time-frequency window is determined by an index of a preamble of the wireless communication system.