【資料名稱(chēng)】：NOKIAOMC常用公式整理.doc

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【資料語(yǔ)言】：英文

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1SDCCH drop failure
1.1相關(guān)計(jì)算器Counter說(shuō)明
SDCCH_RADIO_FAIL： A coverage problem.for example:MS moves out from timing advance Common in connection with coverage problems. Triggered also if the MS user clears the call in the SDCCH phase.
SDCCH_RF_OLD_HO :Transactions have ended due to an old channel failure in HO.For instance, a failure in Directed Retry drops the call and triggers this counter in the source cell.
SDCCH_ABIS_FAIL_CALL:Transactions have ended due to Abis problems. Missing channel activation ack or if no indication of call establishment has been received. Augmented when the BSC receives an Establish indication the contents of which are corrupted, or more commonly when a timer (T3101, default 3 sec) expires while waiting for the Establish indication. The Establish indication is the first message sent from the BTS to the BSC after the MS has successfully accessed the SDCCH.
• Ghost seizures which accidentally have a valid establishment cause and are detected on SDCCH,
increment this counter.
• Multiple SDCCH seizures may cause these failures. If the MS has to send multiple random accesses for a call or location update, it is possible that there will be multiple reservations of SDCCH for one mobile naturally the mobile can use only one of these and the rest will eventually time out and result in sdcch_abis_fail_call. One reason for multiple SDCCH seizures can be DL interference.
• Too short frequency&BSIC reuse distance may cause HO burst from one cell to be interpreted as RACH bursts in another cell causing false SDCCH seizures. This reason may be suspected if there are short, 2 - 3 second peaks with high blocking rate on SDCCH.
• A more rare yet possible reason are failing LUs.