Measurement Counter
L01029:IPPM_FORWARD_JITTERMEANSQUARE
Description
This measurement provides the mean square value of jitters of an IPPM link from the BSC to the BTS in a granularity period.
NOTE: In Abis over IP mode, one service connection between the BSC and the BTS is mapped onto one IPPM link. Four types of IPPM services are supported: CS voice, CS data, PS HighPRI, and PS LowPRI. The signaling connection between the BSC and the BTS is not mapped onto any IPPM link.
Unit
None.
Measurement Point
The counter is measured on the BSC side, as shown in Figure 1.
Formula
IPPM_FORWARD_JITTERMEANSQUARE = ∑ (IPPM_FORWARD_JITTER - IPPM_FORWARD_JITTER_AVE)2
IPPM_FORWARD_JITTERMEANSQUARE: means square value of forward jitters
IPPM_FORWARD_JITTER: jitter value of single packet on the downlink.
IPPM_FORWARD_JITTER _AVE: average jitter value of packets on the downlink.
Assume that the IPPM detection packet is sent every 100 ms, the sending sequence over the downlink IPPM is D (D0, D1, D2……Dn), and the interval of sending packets is 100 ms. The interval of receiving packets on the BTS is T (T0, T1, T2……Tn-1), Ti specifies the interval between Di+1 and Di. The jitter value is J (T0 - 100 ms, T1 - 100 ms, T2 - 100 ms……Tn-1 - 100 ms). A negative value indicates a negative jitter, and a positive value indicates a positive jitter.