Ultra-wideband communication systems and methods

• US 20080225963A1
• Filed: 10/25/2007
• Published: 09/18/2008
• Est. Priority Date: 09/25/2000
• Status: Abandoned Application

• Current Assignee: Intellectual Ventures Holding 73 LLC (Intellectual Ventures LLC)
• Original Assignee: Intellectual Ventures Holding 73 LLC (Intellectual Ventures LLC)
• Inventors: Lakkis, Ismail
• Application Number:
  US11/978,049
• Publication Number:
  US 20080225963A1
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 1/7163 using impulse radio
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/71635 Transmitter aspects H04B1/7174 takes precedence
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

Systems and methods of ultra-wideband communication are provided. In one embodiment, an ultra-wideband communication system divides a stream of data conveying symbols into a plurality of unspread substreams. A common spreading code is generated at the ultra-wideband transmitter, and each of the unspread substreams are spread using the common spreading code to form a plurality of spread substreams. The spread substreams are combined to form a composite signal that is transmitted. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Claims

1. A method of ultra-wideband communication, comprising:

dividing a stream of data conveying symbols into a plurality of unspread substreams at an ultra-wideband transmitter;

generating a common spreading code at the ultra-wideband transmitter;

spreading each of the unspread substreams using the common spreading code to form a plurality of spread substreams;

combining the plurality of spread substreams to form a composite signal; and

transmitting the composite signal from the ultra-wideband transmitter.

2. The method of claim 1, wherein the step of transmitting the composite signal from the ultra-wideband transmitter comprises transmitting a plurality of discrete electromagnetic pulses, with each pulse having a duration that can range between about 10 picoseconds to about 1 microsecond.

3. The method of claim 1 further comprising:

receiving the composite signal at an ultra-wideband receiver; and

despreading the composite signal at the ultra-wideband receiver using a mismatched filter to generate a baseband signal;

where the mismatched filter comprises a matched filter and a sidelobe suppression filter.

4. The method of claim 1, wherein the spreading activity comprises temporally offsetting the spreading of each of the unspread substreams so that the spread substreams correspond to unspread substreams spread by cyclical variations of the common spreading code.

5. The method of claim 1, wherein the dividing of the stream of data conveying symbols produces successive blocks of symbols, where each block of symbols is comprised of symbols concurrently present in each unspread substream, each block having a block period, and the temporally offsetting and the combining of substreams are configured so that for a portion of each block period the composite signal is responsive to symbols from more than one block.

6. The method of claim 1, wherein the dividing of the stream of data conveying symbols produces successive blocks of symbols, where each block of symbols is comprised of symbols concurrently present in each unspread substream, each block having a block period, and the temporally offsetting and the combining of substreams are configured so that for a portion of each block period the composite signal is responsive to symbols from only common blocks.

7. The method of claim 3, wherein the step of dividing of the stream of data conveying symbols and the spreading each of the unspread substreams produce M unspread substreams and M spread substreams, where M is an integer number;

and

wherein the step of combining combines the M spread substreams so that, for each block P of the M spread substreams occur first in the composite signal, where P is an integer number less than M; and

wherein the step of combining additionally comprises, for each block, repeating the P spread substreams so that the P spread substreams also occur last in the composite signal; and

where between the step of receiving and despreading the composite signal, a step of removing the first-occurring P spread substreams from the communication signal is performed.

8. The method of claim 1, further comprising applying block encoding to an input stream of data so that encoding blocks coincide with said successive blocks of symbols.

9. The method of claim 3, further comprising equalizing the composite signal at the ultra-wideband receiver following the despreading activity using a maximum likelihood sequence estimation (MLSE) equalizer.

10. The method of claim 3, further comprising:

performing a first time-frequency domain transformation on the unspread substreams at the ultra-wideband transmitter prior to the spreading activity; and

performing a second time-frequency domain transformation on the composite signal at the ultra-wideband receiver prior to the despreading activity.

11. The method of claim 10, further comprising equalizing the communication signal at the ultra-wideband receiver following the second time-frequency domain transformation using a frequency domain equalizer.

12. The method of claim 4, wherein the cyclical variations of the common spreading code are applied to the unspread substreams as a matrix in a cyclic Toeplitz form.

13. The method of claim 3, wherein the ultra-wideband receiver is a first ultra-wideband receiver, the mismatched filter is a first mismatched filter, the baseband signal is a first baseband signal, and the method additionally comprises:

receiving the composite signal at a second ultra-wideband receiver;

despreading the composite signal in the second ultra-wideband receiver using a second mismatched filter to generate a second baseband signal;

generating the stream of data-conveying symbols as a time division multiple access (TDMA) stream having a plurality of time slots wherein a first one of the plurality of time slots is assigned to the first ultra-wideband receiver and a second one of the plurality of time slots is assigned to the second ultra-wideband receiver;

evaluating the first baseband signal at the first ultra-wideband receiver to detect the first one of the time slots; and

evaluating the second baseband signal at the second ultra-wideband receiver to detect the second one of the time slots.

14. The method of claim 1, wherein the ultra-wideband transmitter is a first ultra-wideband transmitter and the composite signal is a first composite signal, the first transmitter is configured so that the first composite signal substantially occupies a predetermined spectrum and the first composite signal is detectable throughout a first radio coverage area, further comprising the step of:

transmitting a second composite signal from a second ultra-wideband transmitter, the second composite signal substantially occupying the predetermined spectrum and being detectable throughout a second radio coverage area which is adjacent to the first radio coverage area.

15. An ultra-wideband communication system comprising:

a demultiplexer for dividing a stream of data conveying symbols into a plurality of unspread substreams;

a spreading section coupled to the demultiplexer and configures to generate a plurality of spread substreams from the plurality of unspread substreams;

a combining section coupled to the spreading section and configured to form a composite signal from the plurality of spread substreams; and

a transmission section coupled to the combining section and configured to transmit the composite signal over an ultra-wideband communication channel.

16. The system of claim 15, wherein the composite signal transmitted by the transmission section comprises a plurality of discrete electromagnetic pulses, with each pulse having a duration that can range between about 10 picoseconds to about 1 microsecond.

17. The system of claim 15, wherein each of the plurality of spread substreams corresponds to each of the plurality of unspread substreams modulated by a common spreading code.

18. The system of claim 15, wherein each of the plurality of spread substreams corresponds to each of the plurality of unspread substreams modulated by cyclic variations of a common spreading code.

19. The system of claim 15, wherein the composite signal is a first composite signal, with the ultra-wideband communication system further comprising:

a receiving section configured to receive a second composite signal from the ultra-wideband communications channel; and

a despreading section coupled to the receiving section, the despreading section being configured to generate a baseband signal in response to the second composite signal.

20. The system of claim 15, wherein the demultiplexer produces successive blocks of symbols, where each block includes symbols concurrently present in each unspread substream, and each block has a block period, and wherein the spreading section is configured so that for a portion of each block period the composite signal is responsive to symbols from two different blocks.

21. The system of claim 15, further comprising a time division multiple access (TDMA) modulation section coupled to the demultiplexer, the TDMA modulation section being configured so that the composite signal is a TDMA signal for which recipients are distinguished from one another by being assigned to different time slots.

22. The system of claim 15, wherein the transmission section is a first transmission section, and the composite signal is a first composite signal, and the ultra-wideband communication system has a first and a second adjacent radio coverage areas, and the ultra-wideband communication system further comprises:

a second transmission section configured to transmit a second composite signal to the second adjacent radio coverage area over an ultra-wideband communication channel, the first and the second composite signals being transmitted using a common spectrum.

23. The system of claim 19, wherein:

the demultiplexer produces successive blocks of M symbols that concurrently influence the unspread substreams, where M is an integer number;

the spreading section is configured to produce M spread substreams, the M spread substreams being responsive to symbols only from common blocks;

the combining section is configured so that, for each block, P of the M spread substreams occur first in the composite signal, where P is an integer number less than M;

the combining section is further configured so that, for each block, the P spread substreams are repeated so that the P spread substreams also occur last in the composite signal; and

wherein the ultra-wideband communication system further comprises;

a cyclic prefix removal section coupled between the receiving and the despreading sections for removing the first-occurring P spread substreams from the composite signal.

24. The system of claim 19, further comprising a maximum likelihood sequence estimation (MLSE) equalizer communicating with the despreading section.

25. The system of claim 19, further comprising:

a first time-frequency domain transformation section coupled between the demultiplexer and the spreading section;

a second time-frequency domain transformation section coupled between the receiver and the despreading section, wherein the despreading section comprises a frequency domain equalizer.