Enhancement: Enhancements In WiMAX

Power Control

Algorithms of power control are applied to enhance the general performance of the system, it is deployed by the base station sending power control information to every Customer Premise Equipments (CPEs) to control the transmit power level so that the level inward bound at the base station is at a fixed level. In a dynamical changing fading environment this pre-determined performance level indicates that the CPE only broadcasts sufficient power to meet this constraint. The communication would be that the CPE broadcast level is supported on worst case circumstances. The power control decreases the general power consumption of the CPE and the possible interference with other base stations. For Line-of-Sight (LOS) the transmission power of the CPE is approximately comparative to its distance from the base station, for Non-Line-Of-Sight (NLOS) it is also closely dependant on the clearance and barriers.  (Martin K, Holger K, Lizhi C Z)

Error Detection Techniques

WiMAX have built-in error detection techniques to reduce the system Signal to Noise Ratio (SNR) obligations. Convolutional Encoding, Strong Reed Solomon FEC, and interleaving algorithms are used to identify and correct errors to enhance throughput. These strong error correction techniques assist to recover corrupted frames that may have been missing due to frequency selective fading or burst errors. To remove the errors, Automatic Repeat Request (ARQ) is used that cannot be corrected by the FEC by resending the error-ed information again. This notably improves the Bit Error Rate (BER) performance for a similar maximum level. (Deepak Boppana, 2005)

See Also:

OFDM (Orthogonal Frequency Division Multiplexing)

WiMAX & IMT-Advanced

Sub Channelization & Transmission Diversity

Antennas & Adaptive Modulation