User's Manual

User

AN-100U/UX Base Station

Manual

2.5.2 Time Division Duplexing (TDD)

The base station system uses time division duplexing (TDD) to transmit and receive on

the same RF channel, or using separate RF channels using half-duplex FDD (HD-FDD)

mode (AN-100U only). These are both non-contention based methods for providing an

efficient and predictable two-way PTP or PMP cell deployment. All uplink and downlink

transmission scheduling is managed by the base station. The base station sends data

traffic to subscribers, polls for grant requests, and sends grant acknowledgements based

on the total of all traffic to all subscribers.

2.5.3 Coding Rate

Each burst of data transmitted over the wireless interface is padded with redundant

information, making it more resistant to potential over-the-air errors. The coding rate is

the ratio of user data to the total data transmitted including the redundant error

correction data. The base station supports coding rates of 1/2, 2/3, and 3/4.

2.5.4 Modulation

The modulation technique specifies how the data is coded within the OFDM carriers.

The base station supports BPSK, QPSK, 16 Quadarature Amplitude Modulation (QAM),

and 64 QAM modulation.

2.5.5 Reed Solomon Error Correction

Outer Reed-Solomon and inward Convolution Coding (RS-CC) error correction is

enabled for all traffic rates, with the exception of BPSK 1/2 where only inward

Convolution Coding is used. These low-level processes can correct bursts of errors in

received messages and reduce the number of retransmissions.

2.5.6 Time Synchronization

When operating two or more collocated base stations, transmitter operations MUST be

synchronization to minimize inter-sector interference. Each base station has a

synchronization port located on the front panel to receive synchronization pulses.

2.6 Deployment Models

The base station supports point to point (PTP) and point to multipoint (PMP) scenarios.

Figure 4: System - PTP Line of Sight Deployment