Method and apparatus of two stage scaling and quantization for coded communication systems

1. An apparatus comprising:

a first quantizer circuit configured to generate a first intermediate signal in response to (i) an input signal and (ii) a first scaling signal, wherein said first quantizer circuit has a first bit-width;

a memory configured to (i) store said first intermediate signal and (ii) present a second intermediate signal, in response to an address signal; and

a second quantizer circuit configured to generate an output signal in response to (i) said second intermediate signal and (ii) a second scaling signal, wherein said second quantizer circuit has a second bit-width greater than said first bit-width of said first quantizer.

2. The apparatus according to claim 1 , wherein said first and second scaling signals are calculated in response to one or more physical conditions that change more slowly than one or more conditions of said input signal.

3. The apparatus according to claim 2 , wherein said first and second scaling signals are applied to a number of soft values of received symbols.

4. The apparatus according to claim 1 , further comprising:

a control circuit configured to generate said first and second scaling signals in response to said input signal.

5. The apparatus according to claim 4 , wherein said control circuit is further configured to generate said address signal.

6. The apparatus according to claim 1 , wherein said input signal is generated with an automatic gain control circuit.

7. The apparatus according to claim 1 , wherein said memory comprises a deinterleaver memory.

8. The apparatus according to claim 1 , wherein said first quantizer circuit implements quantization at said first bit-width and scaling at a first scaling value.

9. The apparatus according to claim 1 , wherein said second quantizer circuit implements quantization at said second bit-width and scaling at a second scaling value.

10. The apparatus according to claim 1 , wherein said apparatus is implemented in a CDMA system.

11. An apparatus comprising:

first quantizer means for generating a first intermediate signal by quantizing a product of (i) an input signal and (ii) a first scaling signal, wherein said first quantizer means has a first bit-width;

means for (i) storing said first intermediate signal and (ii) presenting a second intermediate signal in response to an address signal; and

second quantizer means for generating an output signal in response to (i) said second intermediate signal and (ii) a second scaling signal, wherein said second quantizer means has a second bit-width greater than said first bit-width of said first quantizer.

12. A method for quantizing a coded signal comprising the steps of:

(A) generating a first intermediate signal by quantizing a product of (i) an input signal and (ii) a first scaling signal, wherein step (A) operates at a first bit-width;

(B) storing said first intermediate signal and presenting a second intermediate signal, in response to an address signal; and

(C) generating an output signal by quantizing (i) said second intermediate signal and (ii) a second scaling signal, wherein step (C) operates at a second bit-width greater than said first bit-width of step (A).

13. The method according to claim 12 , wherein said first and second scaling signals are calculated in response to one or more physical conditions that change more slowly than one or more conditions of said input signal.

14. The method according to claim 13 , wherein said first and second scaling signals are applied to a number of soft values of received symbols.

15. The method according to claim 12 , further comprising:

generating said first and second scaling signals in response to said input signal.

16. The method according to claim 12 , further comrpsing:

generating said address signal.

17. The method according to claim 12 , wherein said input signal is generated with an automatic gain control circuit.

18. The method according to claim 12 , wherein step (A) implements quantization at said first bit-width and scaling at a first scaling value.

19. The method according to claim 12 , wherein step (C) implements quantization at said second bit-width and scaling at a second scaling value.