Receiver processing systems

• US 7,295,597 B2
• Filed: 01/24/2003
• Issued: 11/13/2007
• Est. Priority Date: 01/25/2002
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fitton, Michael Philip, Rizvi, Khurram Ali, Chow, Yuk Ching
• Primary Examiner(s): Ghayour; Mohammed
• Assistant Examiner(s): GHULAMALI, QUTBUDDIN
• Application Number:
  US10/350,037
• Publication Number:
  US 20040017843A1
• Time in Patent Office: 1,754 Days
• Field of Search: 375/316, 375/147, 375/148, 375/150, 375/260, 375/243, 375/245, 375/258, 375/149, 375/141, 348/400, 348/403, 348/405, 370/342, 370/343, 370/441, 370/442, 713/322
• US Class Current: 375/148
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/71075 Parallel interference cancellation
• CPC Class Codes: H04J 13/0077 Multicode, e.g. multiple codes assigned to one user

Abstract

A multicode receiver for receiving data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the receiver having intercode interference suppression, the receiver including a multicode spread spectrum receiver to provide a set of data estimates having a plurality of estimates of data carried by the plurality of spread spectrum signals, one estimate for each spread spectrum signal, a plurality of respreaders to respread the plurality of data estimates, a plurality of interference suppressers, at least one for each of the plurality of spreading codes, each at least one interference suppresser for each code being configured to suppress respread data estimates for the spread spectrum signals of the other codes, from a received signal, a plurality of rake fingers each having the plurality of interference suppressers, and a plurality of rake combiners, one for each of the plurality of spreading codes.

Claims

1. A multicode receiver for receiving data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the receiver having intercode interference suppression, the receiver comprising:

a multicode spread spectrum receiver to provide a set of data estimates comprising a plurality of estimates of data carried by said plurality of spread spectrum signals, one estimate for each said spread spectrum signal;

a plurality of respreaders to respread said plurality of data estimates;

a plurality of interference suppressers, at least one interference suppressor for each of said plurality of spreading codes, each said at least one interference suppresser for each code being configured to suppress respread data estimates for the spread spectrum signals of the other codes from a received signal;

a plurality of rake fingers each comprising respective said plurality of interference suppressers; and

a plurality of rake combiners, one for each of said plurality of spreading codes.

2. A multicode receiver as claimed in claim 1 wherein said multicode spread spectrum receiver comprises a multicode rake receiver.

3. A multicode receiver as claimed in claim 1 further comprising a channel estimator to modify each said data estimate by a channel response estimate.

4. A multicode receiver as claimed in claim 1 wherein a said interference suppresser comprises an adjustable weight to weight a said respread data estimate.

5. A multicode receiver as claimed in claim 1 wherein said multicode spread spectrum receiver comprises a multicode receiver as claimed in any preceding claim.

6. A multicode receiver as claimed in claim 1 suitable for a mobile communications system, and further comprising means to suppress interference from a pilot or a control channel of said mobile communications system.

7. A multicode receiver as claimed in claim 1 configured for space-time transmit diversity STTD reception and further comprising means to suppress interference between spread spectrum signals received from different transmit antennas.

8. A multicode receiver as claimed in claim 7 suitable for a mobile communications system, and further comprising means to suppress interference from a pilot or a control channel of said mobile communications system.

9. A multicode receiver for receiving data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the receiver having intercode interference suppression, the receiver comprising:

a multicode spread spectrum receiver to provide a set of data estimates comprising a plurality of estimates of data carried by said plurality of spread spectrum signals, one estimate for each said spread spectrum signal;

a plurality of respreaders to respread said plurality of data estimates;

a plurality of interference suppressers, at least one for each of said plurality of spreading codes, each said at least one interference suppresser for each code being configured to suppress respread data estimates for the spread spectrum signals of the other codes from a received signal;

a plurality of rake fingers each comprising said plurality of interference suppressers; and

a plurality of rake combiners, one for each of said plurality of spreading codes, wherein said multicode spread spectrum receiver is configured to provide a plurality of sets of data estimates, each set corresponding to a multipath component of a received signal, wherein said plurality of respreaders comprises one respreader for each said data estimate of each said set, an wherein each of said plurality of rake fingers is configured to receive a respread set of said data estimates.

10. A method of suppressing intercede interference in a multicode receiver for receiving data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the method comprising:

using a multicode spread spectrum receiver to provide a set of data estimates comprising a plurality of estimates of data carried by said plurality of spread spectrum signals, one estimate for each said spread spectrum signal;

respreading said plurality of data estimates;

suppressing with a plurality of rake fingers, each including a plurality of interference suppressers, from a received signal for each code, the respread data estimates for the spread spectrum signals of the other codes of the received signal; and

combining with a plurality of rake combiners, one for each of said plurality of spreading codes, signals received from said plurality of rake fingers.

11. A computer readable medium storing a computer code, which when executed by a computer, suppresses intercode interference of data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the code comprising instructions to:

provide a set of data estimates comprising a plurality of estimates of data carried by said plurality of spread spectrum signals, one estimate for each said spread spectrum signal;

respread said plurality of data estimates;

suppress with a plurality of rake fingers, each rake including a plurality of interference suppressers, from a received signal for each code, the respread data estimates for the spread spectrum signals of the other codes of the received signal; and

combine, with a plurality of rake combiners, one for each of said plurality of spreading codes, signals received from said plurality of rake fingers.

12. An interference suppresser for a rake receiver, the rake receiver being configured for demodulating a first multicode signal from a received signal comprising a plurality of substantially orthogonal multicode signals, the interference suppresser comprising:

a signal input for a received signal;

a plurality of sets of interference estimate inputs, one set for each finger of the rake receiver;

a plurality of outputs, one for each finger of the rake receiver, each output and each set of inputs being associated with a multipath component of the received signal, said each set of inputs comprising inputs for interference estimates for each multicode other than the first multicode;

a summer for each set of inputs to sum the interference estimates for each multicode; and

a plurality of subtractors between the signal input and each said output, the subtractors between the signal input and a said output being configured to receive the summed sets of interference estimates from inputs associated with each multipath component except the multipath component with which the output is associated.

13. An interference suppresser as claimed in claim 12 further comprising:

a plurality of weighting means to weight the interference estimates input at said plurality of sets of interference estimate inputs.

14. An interference suppresser as claimed in claim 13 wherein each said weighting means has an adjustable weight.

15. An interference suppresser for a multicode rake receiver, the multicode rake receiver comprising a plurality of rake receivers, one for each said multicode signal, the interference suppresser comprising a plurality of interference suppressors, each as claimed in claim 12, and each sharing a common said signal input.

16. An interference suppressor as claimed in claim 15 further comprising:

a plurality of weighting means to weight the interference estimates input at said interference estimate inputs.

17. An interference suppresser as claimed in claim 16 wherein each said plurality of weighting means has an adjustable weight.

18. A computer readable medium storing a computer code, which when executed by a computer, demodulates a first multicode signal from a received signal including a plurality of substantially orthogonal multicode signals, the code comprising instructions to:

receive the received signal;

estimate a plurality of sets of interference inputs, one set for each finger of a rake receiver;

output a plurality of signal outputs, one for each finger of the rake receiver, each output and each set of inputs being associated with a multipath component of the received signal, each set of inputs comprising inputs for interference estimates for each multicode other than the first multicode;

sum for each set of inputs the interference estimates for each multicode; and

receive the summed sets of interference estimates from inputs associated with each multipath component except the multipath component with which the output is associated.