Iterative multi-stage detection technique for a diversity receiver having multiple antenna elements
View Patent ↗An iterative multistage detection system and method for orthogonally multiplexing K channels onto a signal processing chain using N orthogonal sequences of length N. The K channels include a first set of N channels and a second set of M channels (the M channels being separate and distinct from the N channels), where K=N+M. In a first iteration, interference from the first set of N channels imparted on the second set of M channels is removed from the multiplexed signal, thereby enabling the symbol values associated with the second set of M channels to be reliably estimated. In a second iteration, interference from the second set of M channels imparted on the first set of N channels is removed from the first set of N channels, thereby enabling the symbol values associated with the first set of N channels to be reliably estimated.
1. A method for multiplexing K channels on to a receiver chain, the K channels including N channels corresponding to N antenna elements and M channels corresponding to M antenna elements, the method comprising:
spreading each of the N channels according to a corresponding one of N orthogonal sequences so as to form N spread channels;
overlaying a first scrambling sequence onto the N spread channels so as to form a first set of N channels;
spreading each of the M channels according to one of the N orthogonal sequences so as to form M spread channels;
overlaying a second scrambling sequence on to the M spread channels so as to form a second set of M channels;
combining the first set of N channels and the second set of M channels so as to form K multiplexed channels; and
providing the K multiplexed channels to the receiver chain.
2. The method according to claim 1 , comprising orthogonally multiplexing said K multiplexed channels to the receiver chain.
3. The method according to claim 1 , comprising:
generating a first composite signal comprising N orthogonal sequences derived from the N channels; and
scrambling the first composite signal to generate said first set of N channel signals.
4. The method according to claim 3 , comprising:
generating a first composite signal comprising M orthogonal sequences derived from the M channels, wherein the M orthogonal sequences are a subset of the N orthogonal sequences; and
scrambling the first composite signal to generate said second set of M channel signals.
5. The method according to claim 1 , comprising combining said first set of N channel signals and said second set of M channel signals to generate said K multiplexed channels.
6. The method according to claim 1 , comprising downconverting via the receiver chain, the K multiplexed channels to corresponding baseband multiplexed channels.
7. The method according to claim 6 , comprising generating K separate signals from said downconverted baseband multiplexed channels.
8. The method according to claim 1 , comprising canceling interference due to the first set of N channels from the second set of M channels.
9. The method according to claim 1 , comprising canceling interference due to the second set of M channels from the first set of N channels.
10. A system for multiplexing K channels on to a receiver chain, the K channels including N channels corresponding to N antenna elements and M channels corresponding to M antenna elements, the system comprising:
at least one processor that spreads each of the N channels according to a corresponding one of N orthogonal sequences so as to form N spread channels;
said at least one processor enables overlaying a first scrambling sequence onto the N spread channels so as to form a first set of N channels;
said at least one processor spreads each of the M channels according to one of the N orthogonal sequences so as to form M spread channels;
said at least one processor overlays a second scrambling sequence on to the M spread channels so as to form a second set of M channels;
said at least one processor combines the first set of N channels and the second set of M channels so as to form K multiplexed channels; and
said at least one processor provides the K multiplexed channels to the receiver chain.
11. The system according to claim 10 , wherein said at least one processor orthogonally multiplexes said K multiplexed channels to the receiver chain.
12. The system according to claim 10 , wherein said at least one processor:
generates a first composite signal comprising N orthogonal sequences derived from the N channels; and
scrambles the first composite signal to generate said first set of N channel signals.
13. The system according to claim 12 , wherein said at least one processor:
generates a first composite signal comprising M orthogonal sequences derived from the M channels, wherein the M orthogonal sequences are a subset of the N orthogonal sequences; and
scrambles the first composite signal to generate said second set of M channel signals.
14. The system according to claim 10 , wherein said at least one processor combines said first set of N channel signals and said second set of M channel signals to generate said K multiplexed channels.
15. The system according to claim 10 , wherein said at least one processor downconverts via the receiver chain, the K multiplexed channels to corresponding baseband multiplexed channels.
16. The system according to claim 15 , wherein said at least one processor generates K separate signals from said downconverted baseband multiplexed channels.
17. The system according to claim 10 , wherein said at least one processor cancels interference due to the first set of N channels from the second set of M channels.
18. The system according to claim 10 , wherein said at least one processor cancels interference due to the second set of M channels from the first set of N channels.
19. A system for multiplexing K channels on to a receiver chain, the K channels including N channels corresponding to N antenna elements and M channels corresponding to M antenna elements, the system comprising:
one or more circuits that spreads each of the N channels according to a corresponding one of N orthogonal sequences so as to form N spread channels;
said one or more circuits enables overlaying a first scrambling sequence onto the N spread channels so as to form a first set of N channels;
said one or more circuits spreads each of the M channels according to one of the N orthogonal sequences so as to form M spread channels;
said one or more circuits overlays a second scrambling sequence on to the M spread channels so as to form a second set of M channels;
said one or more circuits combines the first set of N channels and the second set of M channels so as to form K multiplexed channels; and
said one or more circuits provides the K multiplexed channels to the receiver chain.
20. The system according to claim 19 , wherein said one or more circuits orthogonally multiplexes said K multiplexed channels to the receiver chain.
21. The system according to claim 19 , wherein said one or more circuits:
generates a first composite signal comprising N orthogonal sequences derived from the N channels; and
scrambles the first composite signal to generate said first set of N channel signals.
22. The system according to claim 21 , wherein said one or more circuits:
generates a first composite signal comprising M orthogonal sequences derived from the M channels, wherein the M orthogonal sequences are a subset of the N orthogonal sequences; and
scrambles the first composite signal to generate said second set of M channel signals.
23. The system according to claim 19 , wherein said one or more circuits combines said first set of N channel signals and said second set of M channel signals to generate said K multiplexed channels.
24. The system according to claim 19 , wherein said one or more circuits downconverts via the receiver chain, the K multiplexed channels to corresponding baseband multiplexed channels.
25. The system according to claim 24 , wherein said one or more circuits generates K separate signals from said downconverted baseband multiplexed channels.
26. The system according to claim 19 , wherein said one or more circuits cancels interference due to the first set of N channels from the second set of M channels.
27. The system according to claim 19 , wherein said one or more circuits cancels interference due to the second set of M channels from the first set of N channels.