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PMP 400/430 and PTP 200/230 Series Configuration and User Guide
Chapter 4: Configuring
Most PMP 400/430 Series and PTP 200/230 Series configuration items are identical or very similar to
configuration items in standard FSK Canopy modules. This section discusses those that are new or changed
and also remarks on some that remain unchanged.
Link Operation – 1X/2X/3X
PMP 400/430 and PTP 200/230 Series products offer three levels or speeds of operation – 1X, 2X, and 3X.
If received power is less due to distance between the AP/BHM and the SM/BHS or due to obstructions, or
interference affects the RF environment, the Canopy system will automatically and dynamically adjust links
to the best operation level. Distance, rates and other information associated with the operation levels are
shown in
Table 8
on page 37.
The system chooses its operation rate dynamically, based on Canopy's internal ARQ (Automatic Repeat
reQuest) error control method. With ARQ, every data slot of every frame sent over the air (except downlink
broadcast) is expected to be acknowledged by the receiver, and if acknowledgement is not received, the
data is resent. The sending unit monitors this resend data and adjusts the operation rate accordingly. A
normal system may have links that move from 3X to 2X (or 1X) and back as the RF environment changes.
Furthermore, the links operate independently; normal operation can have a downlink running at 3X while the
uplink RF environment only supports 2X.
The default is for both AP/BHM and SM/BHS to be enabled for 3X operation. An operator may "lock down" a
link to 1X/2X operation or to only 1X operation using the Dynamic Rate Adapt parameter on the SM's/BHS's
Configuration => General page as shown in
operation. An operator may lock down an entire sector to 2X and 1X operation, or to only 1 X operation,
using the Dynamic Rate Adapt parameter on the AP's Configuration => General page. This parameter
locks down uplink or downlink of all links in the sector, and overrides any SM 1X/2X/3X settings. For
example, if an individual link is set for 3X operation at the SM and the sector is set for 1X operation at the
AP, all links in the sector will be locked down to 1X operation.
Figure 25: Dynamic Rate Adapt on AP "Configuration => General" page
In most cases, an operator is well-served to leave the setting at 1X/2X/3X. This allows the system to
automatically and dynamically choose the best rate for each link. Cases when it may be useful to lock down
a link to 1X or 2X include:
If you are having trouble aiming a link or getting it to register, locking the link down to 2X or 1X may
help in some cases.
If the link is suspected to be oscillating between operation rates to the detriment of throughput,
locking the link down may increase throughput. Usually, even if the link is moving rapidly between
operation rates, overall link throughput and sector capacity are highest if the link is left at 3X and
the link can choose its own rate dynamically.
General link troubleshooting
Optimal sector utilization involves having as many links as possible running at 3X. This provides as much
capacity as possible for the sector. As an example, you want to limit throughput to an individual subscriber to
1X rates. This does not mean you should set that link to 1X operation. Use MIR (Maximum Information Rate)
settings to cap the SM's bandwidth use, but let the link run at as high an operation rate as the RF
environment will allow. This ensures that any transmission uses as little "air time" as possible, leaving more
"air time" for other SMs.
pmp-0042 (March 2014)
Figure
25. This parameter locks down the uplink or downlink
Page 52 of 98
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