3GPPFDD HS CQI Decoder

3GPPFDD_HS_CQI_Decoder

Description: Channel decoder for channel quality information
Library: 3GPPFDD, TrCH DeMultiplexers & DeCoders
Class: SDF3GPPFDD_HS_CQI_Decoder
Derived From: 3GPPFDD_HS_CQI_Coding

Parameters

Pin Input

Pin Output

Notes/Equations

1. This model decodes the channel quality information coded using a (20,5) code.
2. Each firing: if CQI_Type=Decimal, 1 CQI_B tokens produced when 20 CQI_S tokens are consumed; if CQI_Type=Binary, 5 CQI_B tokens are produced when 20 CQI_S tokens are consumed.
3. The (20,5) code words are a linear combination of the 5 basis sequences denoted M_i,n in the following table.

   Basis Sequences for (20,5) Code

   i	Mi,0	Mi,1	Mi,2	Mi,3	Mi,4
   0	1	0	0	0	1
   1	0	1	0	0	1
   2	1	1	0	0	1
   3	0	0	1	0	1
   4	1	0	1	0	1
   5	0	1	1	0	1
   6	1	1	1	0	1
   7	0	0	0	1	1
   8	1	0	0	1	1
   9	0	1	0	1	1
   10	1	1	0	1	1
   11	0	0	1	1	1
   12	1	0	1	1	1
   13	0	1	1	1	1
   14	1	1	1	1	1
   15	0	0	0	0	1
   16	0	0	0	0	1
   17	0	0	0	0	1
   18	0	0	0	0	1
   19	0	0	0	0	1

   The CQI values 0 to 30 (defined in [2] ) are converted from decimal to binary to map them to channel quality information bits (1 0 0 0 0) to (1 1 1 1 1), respectively. Information bit pattern (0 0 0 0 0) is not used. The channel quality information bits are a₀, a₁, a₂, a₃, a₄ (where a₀ is LSB and a₄ is MSB). The output code word bits b_i are given by:
   
   where i = 0, ..., 19.
4. The decoding algorithm is:
   • Generate a set of 30 codes for all possible CQI (1 to 30, for example).
   • Calculate the correlation of the received signal with each of the 30 codes.
   • Search the one with the maximum correlation value.
   • Convert to the decimal value to binary value if needed.

References

1. 3GPP Technical Specification TS 25.212 V5.6.0, "Multiplexing and channel coding (FDD)," Release 5.
2. 3GPP Technical Specification TS 25.214 V5.6.0, "Physical layer procedures (FDD)," Release 5.