RESERVED_SWITCH_0_BIT27

·         RTWP represents a measure of UMTS technology: the total level of noise within the UMTS frequency band of any cell. RTWP is related to uplink interference, and its monitoring helps control the call drops, throughput, quality, etc.  ·         RTWP has importance in the capacity management, as it provides information for the Congestion Control regarding Uplink Interference. In UMTS, the uplink interference may vary due to several factors, such as the number of users in the cell, the Service, Connection Types and Conditions of Radio, etc...  ·         Most engineers experiencing exceptionally high level for RTWP measurements for many cells in Huawei UMTS network. Such level (-85....-75dBm) cannot be explained by regular interference caused by mobile phones. So what maybe the cause?

There is a parameter that is not explained in Huawei Hedex, even in the definition of the parameters which is RESERVED_SWITCH_0_BIT27   There is a problem with smart phones, as example the IPhone users on CELL_DCH state when they release the channel in the cell, abnormal cell RTWP moment uplift happens as below   The CELL_DCH state UE RRC release process is as follows:

Step1: RNC sends RRC CONNECTION RELEASE to the UE RRC release through the DCCH

Step2: UE receives a release message; send the RRC Connection Release COMPLETE to the RNC. For the the CELL_DCH state's UE UM mode to send the RRC CONNECTION RELEASE COMPLETE message.

Step 3: RNC received notice NodeB RL release complete message.

Step 4: UE waiting for the T308 timeout retransmission RRC CONNECTION RELEASE COMPLETE message.

Step4 Repeat N308.

RRC CONNECTION RELEASE COMPLETE message when the UE first issued by the RNC received correctly, the NodeB start to execute the release of the wireless link, the UE needs to wait for the timer T308 timeout. If the power control command is not received by the NodeB (which what happens is that its not received, because the Node-B have released the channel from its side), so the UE will by default increase the power thinking that the connection is bad resulting in cell RTWP rising.  

So in conclusion, the terminal side and the network side RL release time is inconsistent, leading to instant increased RTWP. Easy to cause dropped calls, impact KPIs.

  Note: The SRNC may send the RRC CONNECTION RELEASE message several times to

increase the probability of proper reception of the message by the UE. The RRC SNs of these messages are the same. The number of retransmissions and the transmission intervals are determined by the SRNC. If the SRNC does not receive an RRC CONNECTION RELEASE COMPLETE message from the UE after sending the RRC CONNECTION RELEASE message for four times, the SRNC judges that the UE has released the RRC connection.   The solution is as follows: CELL_DCH state the UE release, the RNC first received RRC CONNECTION RELEASE COMPLETE sent by the UE, after a certain time delay release of RL, to ensure the release of the UE and the RNC side RL the same time. Also this will prevent the UE from increasing his power when the Release process begins

To Turn this feature switches need to perform the following MML command: SET UCORRMALGOSWITCH: ReservedSwitch0 = RESERVED_SWITCH_0_BIT27-1;   Gain: RTWP increase can be prevented when UE releases channel resources that may affect CDR greatly .