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Airbridge BTS3606C CDMA Base Station
Product Description
8.1 Abis Traffic Signal Flow in the BTS
This topic describes the Abis traffic signal flow in the BTS. The Abis traffic signals consist of
voice service traffic signals, inband signaling signals, and data service traffic signals.
Forward Traffic Signal Flow
The forward traffic signal flow is as follows:
1.
2.
3.
4.
Reverse Traffic Signal Flow
The reverse traffic signal flow is as follows:
1.
2.
3.
4.
8.2 Abis Signaling Signal Flow in the BTS
This topic describes the Abis signaling signal flow in the BTS. Two types of signals, namely,
BTS control signaling signals and outband signaling signals, are transmitted on the Abis common
signaling channel.
BTS Control Signaling
The BTS control signaling signals contains parameters or control messages sent from the BSC
to the BTS for processing. The BTS control signaling signals are not transmitted as RF signals.
For example, the BSC sends PN codes to the BTS so that the channel boards can process them.
Forward Outband Signaling Signal Flow
The forward outband signaling signal flow is as follows:
Issue 03 (2008-02-25)
The ATM cells or IP packets from the BSC are sent to the BCIM, which reassembles them
and sends them to the CCPM or CECM through the cell bus.
The CCPM or CECM encodes, interleaves, spreads, modulates, and multiplexes the
baseband signals that are sent from the BCIM and carry traffic. Then, the CCPM or CECM
sends the processed baseband signals to the STRM.
The STRM performs demultiplexing, up-conversion, and filtering for the received
baseband signals, and then sends them to the SPAM.
The SPAM amplifies the signals and sends them to the SDFU, which transmits the signals
through the antenna subsystem.
Through the main and diversity antennas, the SDFU receives two paths of CDMA signals
from the MS and then sends them to the STRM.
The STRM performs filtering, down-conversion, and multiplexing for the main and
diversity signals, and then sends them to the CCPM or CECM through the SFP port.
The CCPM or CECM demultiplexes, demodulates, de-interleaves, and decodes the
baseband signals, which carry traffic. Then, the CCPM or CECM sends the processed
signals to the BCIM through the cell bus.
The BCIM converts the received signals into ATM cells or IP packets that are adapted to
Abis link types, and then sends them to the BSC over the E1/T1/FE link.
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8 Signal Flows in the BTS
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