enum egprs_puncturing_values

Neels Hofmeyr nhofmeyr at sysmocom.de
Thu Dec 15 11:45:00 UTC 2016


Today I looked at enum egprs_puncturing_values by coincidence:

  /*
   * Valid puncturing scheme values
   * TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
   */
  enum egprs_puncturing_values {
          EGPRS_PS_1,
          EGPRS_PS_2,
          EGPRS_PS_3,
          EGPRS_PS_INVALID,
  };

I notice that TS 44.060 10.4.8a.3.1 defines further items besides PS_1, 2 and
3, and that our EGPRS_PS_INVALID occupies the value the spec defines as
"MCS-3/P1". I believe that this is rather unfortunate.

  [[[
  Table 10.4.8a.3.1: Coding and Puncturing Scheme indicator field for Header type 3

  bits
  4321      First block CPS
  ----------------------------
  0000      MCS-4/P1
  0001      MCS-4/P2
  0010      MCS-4/P3
  0011      MCS-3/P1
  0100      MCS-3/P2
  0101      MCS-3/P3
  0110      MCS-3/P1 with padding (MCS-8 retransmission)
  0111      MCS-3/P2 with padding (MCS-8 retransmission)
  1000      MCS-3/P3 with padding (MCS-8 retransmission)
  1001      MCS-2/P1
  1010      MCS-2/P2
  1011      MCS-1/P1
  1100      MCS-1/P2

  NOTE: All the other values are reserved for future use
  The bit numbering is relative to the field position.
  ]]]


I would prefer EGPRS_PS_INVALID=-1 (i.e. outside the spec's value range) and
the other enum values named appropriately, like EGPRS_MSC4_P1, so that our enum
actually reflects the spec as advertised. Is there something I'm missing?

These enum values were added in:
  commit 7a05b039c835868eff34308d861edfeb28d1763b
  Author: Aravind Sirsikar <arvind.sirsikar at radisys.com>
  Date:   Wed Mar 23 18:29:45 2016 +0530

Thanks,

~N

-- 
- Neels Hofmeyr <nhofmeyr at sysmocom.de>          http://www.sysmocom.de/
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