Fiber aided wireless network architecture

• US 7,684,709 B2
• Filed: 09/29/2006
• Issued: 03/23/2010
• Est. Priority Date: 09/29/2006
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Ray, Siddharth, Zheng, Lizhong, Medard, Muriel
• Primary Examiner(s): Phan; Hanh
• Application Number:
  US11/540,975
• Publication Number:
  US 20080080868A1
• Time in Patent Office: 1,271 Days
• Field of Search: 398/115, 398/116, 398/117, 398/118, 398/135, 398/66, 398/67, 398/68, 398/69, 398/70, 398/71, 398/72, 398/79, 398/141, 398/74, 398/75, 398/73, 398/76, 398/77, 398/78, 398/59, 398/60, 398/98, 398/99, 398/100, 398/101, 398/102, 398/103, 398/119, 398/136, 398/158, 398/159, 370/310, 370/277, 370/338, 370/328, 370/329, 370/339, 370/432, 370/389, 370/465, 455/422, 455/422.1, 455/427, 455/103, 455/436, 455/445, 455/426
• US Class Current: 398/115
• CPC Class Codes: H04B 10/25754 Star network topology

Abstract

A FAWNA that allows high-speed mobile connectivity by leveraging the speed of optical networks. Specifically, SIMO FAWNA, which comprises a SIMO wireless channel interfaced with a fiber channel through wireless-to-optical interfaces. Received wireless signal at each interface are sampled and quantized prior to transmission. The capacity of the FAWNA approaches the capacity of the architecture exponentially with fiber capacity. It is also shown that for a given fiber capacity, there is an optimal method of operating wireless bandwidth and number of interfaces. An optimal method to divide the fiber capacity among the interfaces is shown, which ensures that each interface is allocated a rate so that noise is dominated by front end noise rather than by quantization distortion. A method is also presented in which, rather than dynamically changing rate allocation based on channel state, a less complex, fixed rate allocation may be adopted with very small loss in performance.

Claims

1. A communications system, comprising:

multiple interfaces configured to receive wireless communications signals and transmit non-decoded signals on at least one communications path, each interface including a conversion unit with a quantizer to convert the wireless communications signals to non-decoded signals by quantizing the wireless communications signals in an encoded state; and

a central processor coupled to the at least one communications path to jointly process the non-decoded signals to produce decoded information, a data rate between the central processor and a given interface being allocated to allow the guantizer to quantize the wireless communications signals with quantization distortion less than noise at a front end of the given interface.

2. The communications system of claim 1 wherein the central processor is configured to jointly process the non-decoded communications using a technique applicable to combining signals received by multiple antennas.

3. The communications system of claim 1 wherein the central processor includes a transmitter unit configured to transmit the decoded information in the form of packets.

4. The communications system of claim 3 wherein the central processor includes a transmitter unit configured to transmit the decoded information to a node in a network.

5. The communications system of claim 1 wherein the central processor is configured to transmit a downstream signal to at least a subset of the multiple interfaces in a substantially simultaneous manner.

6. The communications system of claim 1 wherein the interfaces include a downconverter to downconvert the wireless communications signals to baseband signals without downconverting to intermediate frequency signals.

7. The communications system of claim 6 wherein the interfaces further include a sampler to sample the baseband signals at a rate equal to at least a rate at which the wireless communications signals are received.

8. The communications system according to claim 1 wherein the interfaces are configured to support a given bandwidth to balance quantization errors and power efficiency.

9. The communications system of claim 1 wherein the at least one communications path includes an optical fiber.

10. The communications system of claim 9 wherein multiple interfaces are coupled to the optical fiber.

11. The communications system of claim 10 wherein the optical fiber has a fixed data rate capacity and the interfaces coupled to the optical fiber are selectively enabled to support wireless-to-fiber communications with the fixed data rate capacity.

12. The communications system of claim 1 wherein the number of communication paths are equal to or greater than the number of interfaces.

13. The communications system of claim 1 wherein the interfaces are configured to receive the wireless communications signals at a first data rate and wherein the interfaces are configured to transmit the non-decoded communications to the central processor at a second data rate that is greater than the first data rate.

14. A method of providing a fiber aided wireless network, comprising:

converting a wireless communications signal to a non-decoded communications signal on at least one communications path by;

allocating a data rate to allow quantizing to occur with a quantization distortion less than noise at a front end of a respective interface; and

quantizing the wireless communications signal in an encoded state; and

jointly processing the non-decoded signals on the at least one communications path to produce decoded information.

15. The method of claim 14 wherein jointly processing the non-decoded signals further comprises using a technique applicable to combining signals received by multiple antennas.

16. The method of claim 14 wherein jointly processing the non-decoded signals further comprises transmitting the decoded information in the form of packets.

17. The method of claim 16 wherein jointly processing the non-decoded signals further comprises transmitting the decoded information to a node in a network.

18. The method of claim 14 wherein jointly processing the non-decoded signals further comprises transmitting a downstream signal to at least a subset of the multiple interfaces in a substantially simultaneous manner.

19. The method of claim 14 wherein converting the wireless communications signals further comprises downconverting the wireless communications signals to baseband signals without downconverting to intermediate frequency signals.

20. The method of claim 19 wherein downconverting the wireless communications signals further comprises sampling the baseband signals at a rate equal to at least a rate at which the wireless communications signals are received.

21. The method of claim 14 wherein converting the wireless communications signals further comprises configuring interfaces to support a given bandwidth to balance quantization errors and power efficiency.

22. The method of claim 14 further comprising transmitting via an optical fiber the non-decoded information on the at least one communications path.

23. The method of claim 22 wherein the optical fiber has a fixed data rate capacity and further comprising selectively converting the wireless communications signal to the non-decoded signal at multiple locations along the optical fiber.

24. The method of claim 23 wherein the number of communication paths is equal to or greater than the number of locations at which converting the wireless communication signals occurs.

25. The method of claim 14 wherein converting the wireless communications signal further comprising receiving the wireless communications signals at a first data rate and transmitting the non-decoded information at a second data rate, wherein the second data rate is greater than the first data rate.