Chapter 4 - Operation and Administration
The default is Enable.
4.2.6.5.7.2 Burst Mode Time Interval
The Burst Mode Time Interval defines the burst size, which is the time in which data frames are sent immediately without contending for the wireless medium.
The range is 1 to the value of the Maximum Burst Duration defined for the Sub- Band.
The default is 5 milliseconds or the value of Maximum Burst Duration defined for the
4.2.6.5.8Adaptive Modulation
The Adaptive Modulation algorithm enables adapting the modulation level of transmitted data to the prevailing conditions of the applicable radio link. The algorithm provides Access Units with simultaneous, adaptive support for multiple Subscriber Units at different modulation levels, as transmission’s modulation level decisions are made separately for each associated SU.
Link quality fluctuates due to various environmental conditions. Dynamically switching between the possible modulation levels increases the probability of using the maximum modulation level suitable for the current radio link quality at any given moment.
When enabled, the Adaptive Modulation algorithm, constantly evaluates the acievable throughput for a particular modulation by counting the number of packets that are successfully transmitted and the packets that are not received and that need to be retransmitted. Based on these statistics, and on each modulation’s specific data rate, it will calculate the real throughput that the unit can support in the current conditions for a particular modulation.
When choosing between modulations, up to a limit, a small number of retransmissions on a higher modulation is compensated by the overall better performance ensured by that modulation. When a critical retransmissions percentage is reached however, it is necessary to decrease the modulation to achieve better throughputs as shown in Table
Table
Modulation | PHY Rate | PHY Rate Difference Compared |
Level | (Mbps) | to Previous Modulation (Mbps) |
Retransmission Percentage
Equivalent to PHY Rate Difference
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