WCDMA3G CCTrCHRMatch

Pin Inputs

Pin Outputs

Notes/Equations

1. This model is used to implement transport channel rate matching. The bit number of current transport channel data is changed to the bit number required by the relevant coded composite transport channel (CCTrCH). Discontinuous transmission indicators are inserted with fixed transport channel positions in downlinks.
   Each firing:

   • for downlinks, Mp × Np × T tokens of out and one token of outSize are produced when T × Nt tokens of TFMax, T tokens of TFCI and S tokens of in are consumed
   • for uplinks, Mp × Np tokens of out and one token of outSize are produced when Nt tokens of TFMax, one token of TFCI and S tokens of in are consumed.

   Refer to the following tables for the values of T, S, and Mp.

   T Values

   TTI	Frame Number in TTI (T)
   TTI_10 ms	1
   TTI_20 ms	2
   TTI_40 ms	4
   TTI_80 ms	8

   
   

   Values

   TrCHType	TF	TTI	Downlink Input Data Size (S)	Uplink Input Data Size (S)
   DCH_8_kbps	0	10 ms	96	312
   	1	20 ms	176	276
   	2	40 ms	336	258
   	3	80 ms	656	252
   DCH_16_kbps	4	10 ms	368	552
   	5	20 ms	688	516
   	6	40 ms	1344	504
   	7	80 ms	2640	495
   DCH_32_kbps	8	10 ms	688	1032
   	9	20 ms	1344	1008
   	10	40 ms	2640	990
   	11	80 ms	5256	986
   DCH_64_kbps	12	10 ms	1980	1980
   	13	20 ms	3900	1950
   	14	40 ms	7740	1935
   	15	80 ms	77162	1929
   DCH_128_kbps	16	10 ms	3900	3900
   	17	20 ms	7740	3870
   	18	40 ms	77402	3858
   	19	80 ms	102693	3851
   DCH_256_kbps	20	10 ms	7740	7740
   	21	20 ms	77402	7716
   	22	40 ms	102693	7702
   	23	80 ms	123125	7695
   DCH_512_kbps	24	10 ms	77402	15432
   	25	20 ms	102693	15404
   	26	40 ms	123125	15390
   	27	80 ms	136719	15380
   DMCH_2_4_kbps	2	40 ms	360	90
   DMCH_12_2_kbps	5	20 ms	804	402
   DMCH_64_kbps	9	20 ms	3900	1950
   DMCH_144_kbps	13	20 ms	8700	4350
   DMCH_384_kbps	17	20 ms	115562	11556
   DMCH_2048_kbps	21	20 ms		61520
   BCH_11_1_kbps	0	10 ms	270
   BCH_12_3_kbps	5	20 ms	2702

   
   

   Mp Values

   Physical Channel Type	Bits per Frame (Mp)
   DL_PhyCHType
   DPCH_15kbps_TF0_T2_P4	60
   DPCH_15kbps_TF2_T2_P4	30
   DPCH_30kbps_TF0_T2_P2	240
   DPCH_30kbps_TF2_T2_P2	210
   DPCH_30kbps_TF0_T2_P4	210
   DPCH_30kbps_TF2_T2_P4	180
   DPCH_30kbps_TF0_T2_P8	150
   DPCH_30kbps_TF2_T2_P8	120
   DPCH_60kbps_TF0_T2_P4	510
   DPCH_60kbps_TF2_T2_P4	480
   DPCH_60kbps_TF0_T2_P8	450
   DPCH_60kbps_TF2_T2_P8	420
   DPCH_120kbps_TF8_T4_P8	900
   DPCH_120kbps_TF0_T4_P8	900
   DPCH_240kbps_TF8_T4_P8	2100
   DPCH_240kbps_TF0_T4_P8	2100
   DPCH_480kbps_TF8_T8_P16	4320
   DPCH_480kbps_TF0_T8_P16	4320
   DPCH_960kbps_TF8_T8_P16	9120
   DPCH_960kbps_TF0_T8_P16	9120
   DPCH_1920kbps_TF8_T8_P16	18720
   DPCH_1920kbps_TF0_T8_P16	18720
   PCCPCH	270
   UL_DPDCHType
   DPDCH_15kbps	150
   DPDCH_30kbps	300
   DPDCH_60kbps	600
   DPDCH_120kbps	1200
   DPDCH_240kbps	2400
   DPDCH_480kbps	4800
   DPDCH_960kbps	9600

2. Model functions
   In rate matching, bits on a transport channel are repeated or punctured. Higher layers assign a rate-matching attribute for each transport channel.
   Notations are:

   Nij for uplink, number of bits in a radio frame before rate matching on transport channel i with transport format combination j; for downlink, an intermediate calculation variable.
   N_il^TTI (used in downlink only) number of bits in a transmission time interval before rate matching on transport channel i with transport format l.
   ΔN_ij for uplink, if positive, number of bits to be repeated in each radio frame on transport channel i with transport format combination j;
   for uplink, if negative, number of bits to be punctured in each radio frame on transport channel i with transport format combination j.
   for downlink, an intermediate calculation variable.
   ΔN_il^TTI (used in downlink only) if positive, number of bits to be repeated in each transmission time interval on transport channel i with transport format l; if negative, number of bits to be punctured in each transmission time interval on transport channel i with transport format l.
   RM_i semi-static rate matching attribute for transport channel i; signalled from higher layers.
   N_data,j total number of bits available for the CCTrCH in a radio frame with transport format combination j.
   Z_ij intermediate calculation variable.
   F_i no. of radio frames in transmission time interval of transport channel i.
   n_i radio frame number in transmission time interval of transport channel i (0 ≤ n_i ≤ F_i).
   q (used in uplink only) average puncturing distance.
   I_F (n_i ) (used in uplink only) inverse interleaving function of first interleaver.
   S(n_i) (used in uplink only) shift of puncturing pattern for radio frame n_i
   TF_i (j) transport format of transport channel i for format combination j.
   TFS(i) set of transport format indices l for transport channel i.
   TFCS set of transport format combination indices j.
   N input data length in rate matching pattern dermination algorithm.
   e_ini initial value of variable e in rate matching pattern determination algorithm.
   e_plus increment of variable e in rate matching pattern determination algorithm.
   e_minus decrement of variable e in rate matching pattern determination algorithm.
   X systematic bit in turbo code.
   Y first parity bit in turbo code.
   Y′ second parity bit in turbo code.
   round toward +∞, that is, integer such that
   round toward -∞, that is, integer such that
   absolute value of x
   The o notation is used to replace an index x when the indexed variable X_x does not depend on the index x. In the left wing of an assignment the meaning is that "X_o = Y" is equivalent to "for all x do X_x = Y".

   TrCHType responds to the maximum possible bit rate of current transport channel. According to S Values, it and TTI determine the input buffer size at pin in. Because variable rate source, the data rate of each transport channel can change from one TTI to another. From input TFCI, the current TF values of all transport channels can be obtained. RM_i can be set through the parameter RM. F_i of the current transport channel is T.
   Function RMatch_deltasize( ) is used to calculate the rate matching parameters deltasize saved in the array deltaSizeP. There are TrCHNum ( equal to Nt) transport channels with RM values saved in the array RMP. Sizes of all transport channels N_ij are stored in the array TrCHFrameSizeP. These transport channels will be rate matched into one frame of CCTrCH with CCTrCHSize equal to M_p *N_p.
   RMatch_deltasize (TrCHFrameSizeP, deltaSizeP, RMP, TrCHNum, CCTrCHSize)
   

   for each
   do
   end for
   
   
   
   for each
   do tmpSum += RMP[i] * TrCHFrameSizeP[i]
   
   
   
   end for

3. Determining rate matching parameters in downlink
   BCH is mapped to PCCPCH. From the S Values and Mp Values tables, one frame data size of BCH is equal to that of PCCPCH. So for BCH, ΔN_ij = 0. Rate matching algorithm of Note 6 is not needed.
   Function DnLk_RM_Parameters( ) is used to determine the downlink rate matching parameters used in the function RMatch_Algorithm( ) in Note 6: N, e ini, e plus, e minus. For downlink, N_data,j does not depend on the transport format combination j and denoted as N_data,o; it is determined by channelization code(s) and equal to Mp × Np in this model. After rate matching, the data size of the current transport channel in TTI is output at pin outSize. The current data size of each transport channel N ilTTI is based on its TF and TTI values as shown in the S Values table. The maximum data size of each transport channel i for downlink is determined by its maximum TF value from input TFMax according to the S Values table. is derived from function RMatch_deltasize( ).
   DnLk_RM_Parameters (TFMax, N_data,o, F_i, N_il^TTI, N, e_ini, e_plus, e_minus)
   if for fixed positions of transport channels

   then // an intermediate calculation variable N_i,o, determined by TFMax and F_i
   Δ N_i,o is calculated by calling function RMatch_deltasize( ) (input parameter TrCHFrameSizeP is based on N_i,o).
   
   if ΔNi,o^TTI = 0
   then for transport channel i, the output data of the rate matching is the same as the input data and the rate matching algorithm of Note 6 does not need to be executed.
   else
   if for convolutional codes or ΔNi,o^TTI > 0 for turbo codes
   then
   // N_max is determined by TFMax

   // for each transmission time interval of transport channel i with TF l
   
   Puncturing if ΔN < 0, repetition otherwise.
   else // ΔNi,o^TTI < 0 for turbo codes
   // for Y sequence
   // for Y′ sequence, the X bits cannot be punctured.
   
   // for each transmission time interval of transport channel i with TF l
   
   Puncturing if ΔN < 0, repetition otherwise.
   end if

   end if
   // for each transport channel, its reserved bit size in one frame of CCTrCH is
   .
   // if the data of one transport channel after rate matching fill incompletely its reserved bit positions, discontinuous transmission (DTX) indications are inserted. DTX indication is denoted by 10 in this model.

   else // for flexible positions of transport channels

   // an intermediate calculation variable N_ij is calculated.
   if the parameter OptimisticTrCHSizes is valid and used
   then N_i,j, i = 1, ..., N_t, can be obtained by OptimisticTrCHSizes.
   These meet the following condition: .
   else // parameter OptimisticTrCHSizes is not valid and not used
   N_i,j =
   end if
   // rate matching ratios RF_i are calculated for each transport channel i.
   // tentative temporary values of Δ N_i,l TTI
   for all transport channel i and any of its transport format l are calculated
   // temporary values of Δ N_i,l TTI are checked and corrected for all j in TFCS
   
   if D > N_{data, o}
   then for i = 1 to N_t
   ΔN_i,j is calculated by calling function RMatch_deltasize( ) (parameter TrCHFrameSizeP is based on N_ij)
   ΔN = F_i * ΔN_i,j
   if then
   end if
   end for
   end if
   end for
   if Δ N_i,l^TTI = 0
   then output data of the rate matching is the same as the input data and the rate matching algorithm of Note 6 does not need to be executed.
   else
   if for convolutional codes or Δ N_il^TTI >0 for turbo codes
   then
   // for each transmission time interval of transport channel i with TF l
   
   Puncturing if Δ N < 0, repetition otherwise.
   else // for Δ N_il^TTI <0 for turbo codes
   // for Y sequence
   // for Y′ sequence. The X bits shall not be punctured.

   

   //for each transmission time interval of transport channel i with TF l
   
   Puncturing if if Δ N < 0, repetition otherwise.

   // After rate matching, each transport channel data size in one frame of
   CCTrCH is
   end if

   end if

   end if

4. Determining rate matching parameters in uplink
   N_data,j is equal to Mp × Np. The current data size of each transport channel Nij is determined by its current TF and TTI as shown in the S Values table. Using function RMatch_deltasize( ), Δ N_ij can be calculated. If Δ N_ij = 0 then the output data of the rate matching is the same as the input data and the rate matching algorithm of Note 6 does not need to be executed.
   Function UpLk_RM_Parameters( ) is used to determine the rate matching parameters used in function RMatch_Algorithm( ) in Note 6: N, e_ini, e_plus, e_minus.
   UpLk_RM_Parameters (N_ij, Δ N_ij, F_i, N, e_ini, e_plus, e_minus)
   if for convolutional codes or Δ N_ij >0 for turbo codes

   then
   if q is even
   then
   where gcd(q,F_i ) means greatest common divisor of q and F_i
   else
   
   end if
   for each x = 0 to F_i -1
   
   end for
   
   
   , if eini = 0 then
   
   Puncturing for Δ N <0, repeating otherwise.

   else // Δ N_ij <0 for turbo codes

   // for Y sequence
   // for Y′ sequence
   
   
   
   if ( q<=2)
   then for x = 0 to F_i -1
   if ( Y sequence ) ; end if
   if ( Y′ sequence) ; end if
   end for
   else
   if q is even
   then
   where gcd(q,F_i) means greatest common divisor of q and F_i
   else
   end if
   for each x = 0 to F_i -1
   
   if (Y sequence) end if
   if (Y′ sequence) end if
   end for

   // for each frame, the rate matching parameters are calculated
   N is as above,
   
   
   Puncturing for Δ N <0, repeating otherwise.

   end if
5. Bit separation for rate matching
   In rate matching, puncturing for turbo codes is done for Y sequence and Y' sequence separately. No puncturing is applied to the X sequence. Therefore, the X, Y and Y' sequence must be separated before the rate matching algorithm is applied.
   For downlink, the rate matching follows channel coding (see the following figure), so bit separation is easily accomplished. The bit stream after channel coding has constant pattern: ..., X, Y, Y', ....
   
   

   Overall Rate Matching Block Diagram in Downlink Where x Denotes Punctured Bit

   For uplink, see the following figure, rate matching is applied after radio frame segmentation.
   
   

   Overall Rate Matching Block Diagram in Uplink Where x Denotes Punctured Bit

   There are two different alternation patterns in bit stream from radio frame segmentation according to the TTI of a transport channel as shown in the Alternation Patterns of Bits from Radio Frame Segmentation in Uplink table. Each radio frame of a transport channel starts with different initial parity type. The Initial Parity Type of Radio Frames of Transport Channel in Uplink table shows the initial parity type of each radio frame of a transport channel with TTI = {10, 20, 40, 80} msec.
   The following tables define a complete output bit pattern from radio frame segmentation.

   Alternation Patterns of Bits from Radio Frame Segmentation in Uplink

   TTI (msec)	Alternation Patterns
   10,40	...X,Y,Y',...
   20,80	...,X,Y',Y,...

   Initial Parity Type of Radio Frames of Transport Channel in Uplink

   TTI (msec)	ni =0	ni =1	ni =2	ni =3	ni =4	ni =5	ni =6	ni =7
   10	X
   20	X	Y
   40	X	Y'	Y	X
   80	X	Y	Y'	X	Y	Y'	X	Y
   ni denotes radio frame indexes

6. Rate matching pattern
   Function RMatch_Algorithm( ) is used to determine the rate matching pattern of input data inP which length is N, according to parameters e_ini, e_plus, e_minus.
   RMatch_Algorithm (inP, N, e_ini, e_plus, e_minus)
   if puncturing is to be performed

   then // initial error between current and desired puncturing ratio
   // index of current bit
   do while m<= N
   // update error
   if e<= 0 then // check if bit number m should be punctured
   puncture bit inP[m]
   // update error
   end if
   
   end do

   else

   // initial error between current and desired puncturing ratio
   // index of current bit
   do while m<= N
   // update error
   do while e <= 0 // check if bit number m should be repeated
   repeat bit inP[m] // a repeated bit is placed directly after the original one
   // update error

   end do
   // next bit
   end do

   end if

References

1. 3GPP Technical Specification TS 25.212 V3.0.0, "Multiplexing and channel coding (FDD)," October 1999.