Hey guys, today I'm going to talk with you the weak coverage problems of eLTE call drop.
The weak coverage mentioned here refers to the downlink and uplink coverage that exceeds the maximum path loss obtained in the link budget. Because the maximum path loss supported by the uplink is different from that supported by the downlink, the uplink is limited before the downlink in LTE. Therefore, the weak coverage mentioned here is classified into uplink weak coverage and downlink weak coverage.
According to the typical configurations of V100R004C00 commercial networks, the PDSCH pilot power is 15.2 dBm (2T2R) and the maximum uplink UE transmit power is 23 dBm. During link budget, the link budget result is closely related to the scenario, edge throughput, and receiver sensitivity.
The following table lists the link budget results.
As shown in the preceding table, the maximum path loss supported by the downlink is 130.8 dB in this scenario (the downlink edge throughput is 1024 kbit/s and at least 39 RBs). Assume that the pilot power is 18.2 dBm, the minimum RSRP supported by the downlink is 18.2 – 130.8 = –112.6. If the downlink RSRP is lower than –112.6 dB, therefore, downlink weak coverage exists. In this scenario (the uplink edge throughput is 64 kbit/s and at least three RBs), the maximum uplink path loss is 126.44 dB, and the minimum uplink RSRP is –103.44 dBm (23 – 12.44). If the uplink RSRP is lower than –103.44 dBm, uplink weak coverage exists. If the uplink or downlink coverage is weak, call drops may occur.
For weak coverage problems, adjust and optimize the parameters based on the actual DT results and engineering parameters.
Thanks a lot!
