User's Guide Part 1

Table Of Contents

Chapter 1: Product description Wireless operation

Adaptive modulation

The PTP 700 series can transport data over the wireless link using a number of different

modulation modes ranging from 256QAM 0.81 to BPSK 0.63. For a given channel bandwidth

and TDD frame structure, each modulation mode transports data at a fixed rate. Also, the

receiver requires a minimum signal to noise ratio in order to successfully demodulate a given

modulation mode. Although the more complex modulations such as 256QAM 0.81 will

transport data at a much higher rate than the less complex modulation modes, the receiver

requires a much higher signal to noise ratio.

The PTP 700 series provides an adaptive modulation scheme where the receiver constantly

monitors the quality of the received signal and notifies the far end of the link of the optimum

modulation mode with which to transmit. In this way, optimum capacity is achieved at all

times. This is one of a number of features which allows the PTP 700 to operate in challenging

non-line of sight radio channels.

Note

LINKPlanner includes an estimate of mean data rate, the data rate provided by each

modulation and the percentage of time spent in each modulation mode.