Configuring - Motorola PMP 400 Series Supplement To User’s Manual

PMP 400 and PTP 200 Series Canopy User Guide Supplement

4 Configuring

Most Canopy Series 400 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.
4.1 LINK OPERATION – 1X/2X/3X
PMP 400 and PTP 200 Series products offer three levels or speeds of operation – 1X, 2X, and 3X
- instead of the two levels offered by standard Canopy. 3X supports a typical maximum aggregate
(sum of up and down) throughput of up to 21 Mbps.. 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 2 on page 12.
Similar to standard Canopy, 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 (expect downlink broadcast) is expected to be acknowledged
by the receiver, and if acknowledgement is not received, the data is resent. The sending unit
monitors these resends, and adjusts the operation rate accordingly. A normal system may have
links that move from 3X to 2X and back (or 1X) as the RF environment changes, or links.
Furthermore, the links operate independently, and it is normal, for example, for the downlink to
run 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 2X and 1X operation, or to only 1 X operation, using the Dynamic Rate Adapt
parameter on the SM's "Configuration => General" page as shown in Figure 3 on page 15 . This
parameter locks down both uplink and downlink 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 and downlink of
all links in the sector, and overrides any SM 1X/2X/3X settings. That is, if an individual link is set
for 3X operation at the SM, but the sector is set for 1X operation at the AP, that link (and all links
in the sector) will be locked down to 1X operation.
Issue 3, January 2009 Page 17 of 45