Chapter 3 - Interfaces and Communications
Confidential and Proprietary Information of ZTE CORPORATION 37
Multiple multiframes constitute a super frame, which is a continuous 51 ×
26 TDMA frame. The period of the super frame is 1326 TDMA frames, i.e.,
6.12s.
A hyper frame consists of 2,048 super frames and its period is 12,533.76 s.
Each period of a hyper frame contains 2,715,648 TDMA frames, that is,
the TDMA FNs (Frame Numbers) range from 0 to 2,715,647.
Compared to the 26 multi-frame and 51-frame multi-frame structures in
the circuit service, the multi-frame structure consisting of 52 TDMA frames
is introduced in the GPRS system. Mapping of logical channels on all
PDCHs (Packet Data Channels) is based on such a frame structure, as
shown in Figure 17.
F
I G U R E
1 7
S
C H E M A T I C
D
I A G R A M O F T H E
5 2 - M
U L T I F R A M E
S
T R U C T U R E
B0
B1
B2
B3
T
T
B4
I
B5
B6
B7
B8
B9
B 1 0
B 1 1 I
5 2 M u ltifra m e s
B 0
B 1 1
B L O C K
～
：
；
T
：
F ra m e fo r P T C C H ; I : I d le F ra m e
The multiframe structure of PDCH contains 12 blocks, each consisting of
four consecutive TDMA frames. There are also two idle TDMA frames and
another two for the Packet Time advance Control CHannel (PTCCH),
making a total of 52 TDMA frames.
In the packet service, the basic composition unit of all packet logical
channels except the PRACH (Packet Random Access Channel) and
PTCCH/U is block.
In a 52 multi-frame, the occupation order of 12 blocks is like this: B0, B6,
B3, B9, B1, B7, B4, B10, B2, B8, B5 and B11.
CS Logic Channel
Channels are divided into physical channels and logic channels.
The timeslot is a basic physical channel. The logical channels are defined
differently depending on the message types transmitted between the BTS
and MS. The logical channels are mapped to the physical channels for the
purpose of transmission.
By type, the logical channels are classified into CS and PS channels. By
function, they are classified into traffic channels and control channels.
1. Traffic channel (TCH)
TCHs, which carry encoded voice signals or subscriber data, include
TCH/FS (TCH/Full Speed) and TCH/HS (TCH/Half Speed).
i. Voice
TCH
Summary of Contents for ZXG10-BTS
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