User's Manual

DragonWave Inc.

Horizon Compact Release 1.01.01 Wireless Ethernet Product User Manual – Volume 1

Note: The average packet throughput is calculated using 64, 128, 256, 512, 1024, 1280, and 1518bytes

Ethernet frames.

** Throughput optimized to fit within required spectral mask limits.

11.6 Adaptive Transmit Power Control (ATPC)

Adaptive Transmit Power Control (ATPC) allows a Horizon Compact system to adjust its transmit power

to compensate for far end signal loss caused by changes in atmospheric conditions e.g. heavy rain.

ATPC maintains the RSL at -50 dB and adjusts the transmit power by up to 20dB as necessary in order to

maintain -50 dB during fade conditions.

RSL threshold levels that trigger power changes, the maximum power change allowed, and a hysteresis

factor are preset at values which optimize the operation of the Horizon Compact system. A fade factor of

5dB/second can be handled.

The Horizon Compact system is able to discriminate between RSL levels that are reduced as a result of

interference and those as a result of genuine path loss, so that ATPC is not invoked unnecessarily.

Some jurisdictions require the use of ATPC so that power levels are kept as low as possible when

wireless communication conditions are good. When ATPC is to be used, if it can be shown that the

maximum power of the system would be used only on infrequent occasions, some jurisdictions will allow a

lower power level to be used in the calculations that determine interference criteria. Th is offers some

advantage to the installation. This lower power is termed the “coordinated power”. The DragonWave

ATPC feature supports a coordinated power parameter.

ATPC is enabled or disabled by issuing the CLI command set atpc [on/off][coordinated power]

The current status of ATPC can be determined by using the CLI command get atpc status.

Note: If ATPC and Advanced Adaptive Modulation (AAM) are both enabled, when AAM is invoked i.e.

modulation scheme switched to a lower level, ATPC is automatically disabled until AAM restores the

original modulation scheme.