Chapter 1: Configuration
Configuring radio parameters
Page
1-210
Table 69 Throughput penalty per modulation
Modulation mode
Throughput penalty for each additional contention slot
2.5 ms frame
5 ms frame
QPSK SISO (1X)
204 kbps
102 kbps
QPSK MIMO (2X)
409 kbps
204 kbps
16-QAM MIMO (4X)
819 kbps
409 kbps
64-QAM MIMO (6X)
1.22 Mbps
614 kbps
256-QAM MIMO (8X)
1.63 Mbps
819 kbps
shows that the throughput penalty for each additional contention slot increases with
modulation mode. The reason is that at higher modulation modes more fragments can be transmitted in
a symbol. If additional symbols are reserved for random access, the number of fragments that cannot be
sent in these symbols is higher at higher modulations, and therefore the throughput penalty is higher.
However, the penalty expressed as a percentage of the throughput is the same for each modulation
mode. For example, if a frame has 80 total symbols, each additional symbol reserved for random access
reduces the sector throughput by 1.25%, regardless of the modulation mode.
Selection of contention slots parameter
The number of contention slots has to be selected according to the specific deployment parameters in
each sector. If the number of contention slots is too small, then latency increases in high traffic periods.
If the number of contention slots is too high, then the maximum capacity is unnecessarily reduced.
The two main contributing factors to the selection of the number of contention slots are the number of
SMs in a sector, and the type of traffic in the sector.
Number of SMs in a sector
If the number of SMs in a sector is large, it is recommended to increase the number of contention slots,
in order to reduce the probability of two or more requests colliding. The suggested contention slot
settings as a function of the number of active Data channels in the sector are shown in
Table 70 Contention slot settings
Number of SMs
Recommended Number of Contention slots
1 to 10
3
11 to 50
4
51 to 150
6
151 and above
8
Summary of Contents for PMP 450 AP
Page 51: ...Chapter 1 Configuration Quick link setup Page 1 23 ...
Page 155: ...Chapter 1 Configuration Configuring security Page 1 127 ...
Page 163: ...Chapter 1 Configuration Configuring security Page 1 135 ...
Page 164: ...Chapter 1 Configuration Configuring security Page 1 136 ...
Page 193: ...Chapter 1 Configuration Configuring radio parameters Page 1 165 ...
Page 194: ...Chapter 1 Configuration Configuring radio parameters Page 1 166 ...
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Page 636: ...Chapter 5 Troubleshooting Logs Page 5 16 Figure 95 SM Authorization log ...