PMP450x Release 22.2 is now available

PMP450x System Release 22.2 is now available at and it is available on cnMaestro.

Release 22.2 serves as a maintenance update to Release 22.1.1, mainly addressing bug fixes. Additionally, it introduces a new feature: Uplink Interference Cancellation for 5 GHz 450m.

Release 22.2 does not support Cambium’s 450v product, which requires the recently released 23.0 software. The 23.0 release does not include support for the Interference Cancellation feature or the other bug fixes and enhancements mentioned in the 22.2 Release Notes.

Features introduced in Release 22.2

Uplink interference cancellation for 5 GHz 450m

The beamforming technology inherent in our 450m products already manages interference in both uplink and downlink directions. With this release, Cambium adds extra software to identify and eliminate uplink interference. The interference cancellation feature requires a license purchase. A free 30-day trial is available per AP when running software version 22.2 or later. The 30-day timer can be initiated at any time by enabling the trial via the Configuration → General page on the 5 GHz 450m AP.

Trial features

Enabling the free trial or purchasing the license does not by itself activate the feature. The feature must now be enabled by setting the UL Interference Cancellation attribute to Enabled via the Advanced MU-MIMO section of the Configuration → Radio page of the AP.

Enabling interference cancellation disables Uplink MU-MIMO scheduling, forcing all Uplink traffic to be scheduled SU-MIMO. No reboot or outage is required to enable or disable the feature. The trial feature setting and feature flag can alternatively be read and set via SNMP.

Name OID Access Syntax
interferenceCancellationTrialMode . read-write INTEGER {disable(0),enable(1)}
interferenceCancellationMode . read-only DISPLAYSTRING
interferenceCancellationTrialPercentageRemaining . read-only INTEGER (0..100)
interferenceCancellation . read-write INTEGER {disable(0), enable(1)}

(all in WHISP-APS-MIB)

There are 2 additional SNMP OIDs available to read the state of the license or trial and determine how many days are remaining on the trial if a permanent enable license has not yet been purchased.

The Cambium suggested method for evaluating this software is to examine the uplink modulations per SM. Compare these modulations after the software is installed and activated with the modulation values before the feature activation. This assessment is most easily conducted via cnMaestro, which offers various options for reviewing per-SM modulation over time. Graphs for this purpose are available per SM in the performance tab of the Monitor and Manage section. Alternatively, cnMaestro-X license holders can generate a spreadsheet of such modulations every 5 minutes or per hour, depending on the selected time interval.

The feature can be easily reversed without a reboot, and MU-MIMO scheduling can be restored by changing the feature flag back to disabled. Operators can also utilize the Link Test with Multiple VCs link test mode via Tools → Link Capacity Test page on the AP for comparison. It is essential to select the MU-MIMO disabled option when running the baseline test with interference cancellation disabled.

When examining modulation levels with the cancellation feature enabled and attempting to compare these with baseline measurements, ensure that the comparison is conducted against 22.2 software with the feature disabled. Avoid comparing against pre-22.2 software, as the 22.2 software includes a correction (see CPY-17544) addressing reported modulation level inaccuracies resulting from 450m link tests.

Additional enhancements in Release 22.2

Products Affected Tracking Description
All PMP radios CPY-18698 With the introduction of Release 22.2, an SNMP read of SysObject (OID previously returned the OID for ucos. This enhancement incorporates the addition of four new OIDs, each corresponding to distinct hardware platform types. These new OIDs are as follows:
  • Canopy SNMP agent OID definition for 450 devices cambium450 OBJECT IDENTIFIER ::= { canopySnmpAgent 257 }
  • Canopy SNMP agent OID definition for 450i devices cambium450i OBJECT IDENTIFIER ::= { canopySnmpAgent 258 }
  • Canopy SNMP agent OID definition for 450m devices cambium450m OBJECT IDENTIFIER ::= { canopySnmpAgent 259 }
  • Canopy SNMP agent OID definition for 450b devices (including MicroPoP) cambium450b OBJECT IDENTIFIER ::= { canopySnmpAgent 260 }
All PMP SMs CPY-18575 Operators request the addition of VLAN VID Remarking to the Radius dictionary for VSA support. Additionally, support for VLAN Priority Remarking is included. Refer to RADIUS Vendor Specific Attributes (VSAs) table of the PMP/PTP 450 Series Configuration Guide for details on configuring these attributes from a AAA Radius Server.

Problems and limitations corrected in Release 22.2

Products Affected Tracking Description
CBRS enabled SMs CPY-18580 CBRS-enabled SMs were stuck in the scanning state after upgrading to 22.1 software.
450m CPY-17544 Correction to the uplink modulation level reported due to 450m link tests. This corrects a longstanding issue with the reported link test modulation rate, which sometimes reported a slightly too low value.