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authorVadim Yanitskiy <vyanitskiy@sysmocom.de>2021-01-11 02:11:18 +0100
committerVadim Yanitskiy <vyanitskiy@sysmocom.de>2021-02-12 00:07:48 +0100
commitf14fb4b949860d81c732cbc6d3e1f60dbb2ecb45 (patch)
treeb407dba73ec8fb422ff5c605cd484f795fcfe8b7
parentf09107c5b0f145dc6ca4fac1203689277e6f0d74 (diff)
TRXD: use different coding for AQPSK in the 'MTC' field
AQPSK is used exclusively on Downlink in VAMOS mode. An AQPSK burst is basically a combination of two Normal Bursts. Each of these two bursts has the same length as defined for GMSK, while both must be using Training Sequences from different sets. Four different sets are defined in 3GPP 45.002, section 5.2.3.1. Therefore we need *two* bits to encode all possible values. Let's rearrange the existing combinations and use '11XX'B for AQPSK. The old combination '011X'B becomes reserved and can be re-purposed. This change is considered to be safe, given that no implementations are known to support AQPSK at the moment of making this change. Change-Id: Ie9b419e4a70fa0eb2888c326ac50d2d40a67a29c Related: SYS#4895, OS#4941, OS#4006
-rw-r--r--common/chapters/trx_if.adoc4
1 files changed, 2 insertions, 2 deletions
diff --git a/common/chapters/trx_if.adoc b/common/chapters/trx_if.adoc
index 7bb8c77..b223151 100644
--- a/common/chapters/trx_if.adoc
+++ b/common/chapters/trx_if.adoc
@@ -482,13 +482,13 @@ also have several synchronization sequences.
+-----------------+---------------------------------------+
| . 0 1 0 X . . . | 8-PSK, 2 TS sets (0..1) |
+-----------------+---------------------------------------+
-| . 0 1 1 X . . . | AQPSK, 2 TS sets (0..1) |
+| . 0 1 1 X . . . | RFU (Reserved for Future Use) |
+-----------------+---------------------------------------+
| . 1 0 0 X . . . | 16QAM, 2 TS sets (0..1) |
+-----------------+---------------------------------------+
| . 1 0 1 X . . . | 32QAM, 2 TS sets (0..1) |
+-----------------+---------------------------------------+
-| . 1 1 X X . . . | RESERVED (0) |
+| . 1 1 X X . . . | AQPSK (Downlink), 4 TS sets (0..3) |
+-----------------+---------------------------------------+
----