User's Manual

40mW ACS User Guide Technical Introduction v

PAS System

TDMA-TDD Frame (5ms)

CS Transmission PHS PS Transmission

PHS

PS #2

PHS

PS #3

PHS

PS #1

CCH

CCH: signaling channel

T2,T4: communication channel (to transmit)

R2,R4: communication chanenl (to receive)

PAS Handset #1: signaling channel, waiting

PAS Handset #2: 2

time slot, calling

PAS Handset #3: 4

time slot, calling

: transmission time slot

: receivin

time slot

: idle time slot

Figure3-5 Wireless Channel Frame Structure

The radio frequency channel allocation diagram shown in Figure3-5 depicts a

typical wireless channel structure, where, 3 subscribers can communicate in single

ACS control mode.

The channels are not preassigned; channels are allocated automatically by a

dynamic channel allocation system. It is an outstanding feature of the PAS system.

With a settled algorithm, the system dynamically chooses a frequency from the

available frequency resources as the communication carrier frequency, and timely

adjusts the frequency as per the signal disturbance. In this sense, the PAS system

is a slow frequency-hopping system.

3.4 Synchronization Technology

The ACS in the system adopts air synchronization technology. Master ACS

synchronizes with other master ACSs via GPS. By receiving the air

synchronization signal from master ACS, slave ACS synchronize with master

ACS. For RPC synchronization solution, please refer to “GSG2 user guide”.

3.5 Self-Adaptive Mode

ACS is a kind of self-adaptive CS, which can adjust its transmission power. The

transmission power ranged from 0mW to 200 mW can be adjusted on-line.

3.6 ACS Operation Mode

ACS adopts the sending after detecting operation mode (receiving then sending).

Before sending signals, ACS detects the utilization of the surrounding

WIRELESS LOCAL LOOP radio channels. According to the signal strength of