User's Manual Part 1
Release8OverviewofCycloneNetworks
Issue2,November2007 Draft5forRegulatoryReview 91
Table 23: Effect of 2X operation on throughput for the SM
Type of SM
Typical Aggregate Rates
1
Sustained
2
Burst
2
Advantage SM
900 MHz
3
4 Mbps 4 Mbps
Any other frequency
band range
14 Mbps 14 Mbps
Regular SM
(at least P9 Hardware Series)
Any frequency band
range except 900 MHz
7 Mbps 14 Mbps
NOTES:
1. Subject to competition among all SMs in the sector.
2. Can be less if limited by the value of Downlink Data set in the
Radio tab of the Configuration page in the AP.
3. All 900-MHz modules are Advantage.
Competition for Bandwidth
When multiple SMs vie for bandwidth, the AP divides its bandwidth among them,
considering their effective CIR and MIR values. However, 2X operation uses bandwidth
twice as efficiently as 1X, even where MIR values apply. This is because, in 2X
operation, the modules transmit their data in 4-level frequency shift keying (FSK), not
2-level as they would in 1X operation. This moves twice the data per slot. Thus, for the
sum of all bandwidth that 2X-eligible customers use, the bandwidth available to the
remaining customers increases by half of that sum when these eligible customers are
transmitting and receiving in 2X operation.
Engineering for 2X Operation
The following priorities should guide your implementation of 2X operation:
◦ In the near half of the distance range of the AP
• identify the customers who use the most bandwidth.
• enable their SMs first for 2X operation.
◦ When you have deployable Cyclone P7 and P8 SMs, do not deploy Cyclone
Advantage SMs or Cyclone P9 SMs beyond half the distance range of the AP.
At this distance, steady and reliable 2X operation typically is not achievable.
Deploy the Cyclone P7 and P8 SMs here.
◦ Wherever practical, implement 25 MHz of channel separation for 2X operation.
Checking Link Efficiencies in 2X Operation
Unlike in 1X operation, efficiencies below 90% on the Link Capacity Test tab in the Tools
web page of the SM may be acceptable for stable operation. An efficiency of 60% in 2X
operation is equivalent to an efficiency of 120% in 1X. If you read efficiency between 60%
and 90%, check the status of 2X operation (as described below) to confirm that the link is
operating at 2X.
Since received signal strength typically varies over time, you should perform link tests at
various times of day and on various days of the week. Efficiencies should consistently be
60% or greater for 2X operation. You may be able to achieve better efficiencies by re-
aiming the SM, mounting it elsewhere, or adding a reflector dish.