Based on Table 8F : Time slot formats for the Downlink in 25.221

How to select (figure out) slotformat ? Let's talk about following table as an example.

Step 1 : Find all the possible slot formats from Table 8F based on Line No (1).

It says this is using SF1, so all the possible slot formats are 10,11,12,13,14,15,16,17,18,19,20,21,22,23,24.

Step 2 : Find all the possible slot formats from the result of Step 1 based on Line No (3).

It says the TFCI code word of the slot is 16 bits. so the possible slot formats are 13,18,23.

Step 3 : Find all the possible slot formats from the result of Step 2 based on Line No (4).

It says the TPC of the slot is 2x2. so the possible slot formats are 18. Now we picked only one cadidate.. so no need for further checking.

Step 4 : Based on Step 3 and Line No (1), (2).. check if this slot is valid.

Ndata for slot : 1396 , based on Slotformat 18 in Table 8F

Number of slots per radio frame : 6, based on line number (1)

Total Number of Bits per radio frame = 1396 x 6 = 8376. This may be acceptable since it is less than 8424 (Line No (2)). But this may be a waste of small space (8424-8376 = 48 bits).

Step 5 : Now let's think if there is any way to fully fill out bits to the max allowed bit rate.

According to Line No (1). This bearer uses 6 slots per radio frame. It means the bearer uses 3 slots per each subframe.

It may not be a good idea to send data without Ntfci and TPC at the first slot, but we are allowed to send data without Ntfci and TPC at following slots within a subframe. In stead of removing the Ntfci and TPC, we can allocate a little bit larger Ndata for that slot and increase the throughput a little bit more.

Let's find the slot format that meets the condition on Line No (1) and carries no TPC (TPC bit = 0) and Ntfci (Ntfci = 0).

What is it ? You can find only one candidate for this. It is slot format 10.

Now I am trying to allocate slot format as shown below.

 

Step 6 : Based on the result of Step 4 and 5, Line No (1), (2).. check if this slot allocation is valid.

i) Ndata for slot 4, subframe 1 (Slot format #18) = 1396

ii) Ndata for slot 5, subframe 1 (Slot format #10) = 1408

iii) Ndata for slot 6, subframe 1 (Slot format #10) = 1408

iv) Ndata for slot 4, subframe 2 (Slot format #18) = 1396

v) Ndata for slot 5, subframe 2 (Slot format #10) = 1408

vi) Ndata for slot 6, subframe 2 (Slot format #10) = 1408

-------------------------------------------------------

Total number of bits = 8424

 

This matches exactly with the number in Line No (2)

Step 7 : Configure RB Setup according to this configuration.

+-dl-CCTrCH-TimeslotsCodes ::= SEQUENCE OPTIONAL:Exist

  +-firstIndividualTimeslotInfo ::= SEQUENCE [0]

  | +-timeslotNumber ::= INTEGER (0..6) [4]

  | +-tfci-Existence ::= BOOLEAN [TRUE]

  | +-midambleShiftAndBurstType ::= SEQUENCE

  | | +-midambleAllocationMode ::= CHOICE [defaultMidamble]

  | | | +-defaultMidamble ::= NULL

  | | +-midambleConfiguration ::= INTEGER (1..8) [4]

  | +-modulation ::= ENUMERATED [mod-QPSK]

  | +-ss-TPC-Symbols ::= ENUMERATED [one]

  | +-additionalSS-TPC-Symbols ::= INTEGER OPTIONAL:Omit

  +-dl-TS-ChannelisationCodesShort ::= SEQUENCE

  | +-codesRepresentation ::= CHOICE [bitmap]

  |   +-bitmap ::= BIT STRING [0000000000000000]

  +-moreTimeslots ::= CHOICE [additionalTimeslots]

    +-additionalTimeslots ::= CHOICE [timeslotList]

      +-timeslotList ::= SEQUENCE OF SIZE(1..maxTS-LCR-1[5]) [2]

        +-DownlinkAdditionalTimeslots-LCR-r4 ::= SEQUENCE

        | +-parameters ::= CHOICE [newParameters]

        |   +-newParameters ::= SEQUENCE

        |     +-individualTimeslotInfo ::= SEQUENCE [0]

        |     | +-timeslotNumber ::= INTEGER (0..6) [5]

        |     | +-tfci-Existence ::= BOOLEAN [FALSE]

        |     | +-midambleShiftAndBurstType ::= SEQUENCE

        |     | | +-midambleAllocationMode ::= CHOICE [defaultMidamble]

        |     | | | +-defaultMidamble ::= NULL

        |     | | +-midambleConfiguration ::= INTEGER (1..8) [4]

        |     | +-modulation ::= ENUMERATED [mod-QPSK]

        |     | +-ss-TPC-Symbols ::= ENUMERATED [zero]

        |     | +-additionalSS-TPC-Symbols ::= INTEGER OPTIONAL:Omit

        |     +-dl-TS-ChannelisationCodesShort ::= SEQUENCE

        |       +-codesRepresentation ::= CHOICE [bitmap]

        |         +-bitmap ::= BIT STRING [0000000000000000]

        +-DownlinkAdditionalTimeslots-LCR-r4 ::= SEQUENCE

          +-parameters ::= CHOICE [newParameters]

            +-newParameters ::= SEQUENCE

              +-individualTimeslotInfo ::= SEQUENCE [0]

              | +-timeslotNumber ::= INTEGER (0..6) [6]

              | +-tfci-Existence ::= BOOLEAN [FALSE]

              | +-midambleShiftAndBurstType ::= SEQUENCE

              | | +-midambleAllocationMode ::= CHOICE [defaultMidamble]

              | | | +-defaultMidamble ::= NULL

              | | +-midambleConfiguration ::= INTEGER (1..8) [4]

              | +-modulation ::= ENUMERATED [mod-QPSK]

              | +-ss-TPC-Symbols ::= ENUMERATED [zero]

              | +-additionalSS-TPC-Symbols ::= INTEGER OPTIONAL:Omit

              +-dl-TS-ChannelisationCodesShort ::= SEQUENCE

                +-codesRepresentation ::= CHOICE [bitmap]

                  +-bitmap ::= BIT STRING [0000000000000000]