Field Guide Change Alert Field Guide Change Information: Name of Change: LTE Mobility Affective Date of Change: 1/20/2014 Change Number: L13A-E-026 Field Guide Reference #: Ericsson LTE Vol. II Equipment Vendor: Ericsson (LTE) Issuer Name: Bobie Solis Issuer Contact #: 925 520 5814 Description of the Change: In the space below, describe at a high level what and why this change is necessary and how it may affect the current systems. This approved Field Guide Alert is sent as part of the normal Field Guide Alert process to communicate a change in the National recommendation for Ericsson LTE configurable parameters. This FGA is dealing with LTE handovers based on the evaluation reported by the UE to the RBS. These measurement reports are used by the RBS to select, prepare and execute the handover from the serving cell to the target cells. This sequence of events is called Event A3. The UE uses A3Offet, HysteresisA3 andTimeToTriggerA3parameterstodeterminewhentotriggerEventA3andfortheUEtosend Measurement Reports. During the early deployment of LTE, we loosened up mobility parameters such as Event A3 to allow adequate optimization of the LTE network when the LTE sites were not initially built one to one. We had since built out the network and needed to speed up handovers to the best servers without causing handover oscillations. The Ue uses the formula below to evaluate the entry to Event A3 to start sending measurement reports: RSRP(target) > RSRS(Serving) +A3Offset + hysteresisA3 cellindividualoffsetEutran RSRP (or RSRQ) (db) Reference Signal Reference Signal or Quality measurements used to compare serving and neighboring cells.

The figure above shows how the parameters are used to trigger Event A3 Ericsson has a feature that minimizes the number of unnecessary handovers to the same cell by reducing fast handovers and repeated handovers. This could reduce signaling load, improve throughput and have better voice quality for VoLTE calls along with improvements in MOS (Mean Opinion Score) and SINR (SignaltoInterferenceplusNoiseRatio).Thelicensekeyneedstobeenabledwiththeparameter LicenseStateHoOscCtrlUe in the eNodeB for this feature to be available for use. The rules used by the feature to determine when to allow and prevent a handover is shown below: TC (sec) Time in current cell TL (sec) Time in Last Cell T1- Time Limit 1 Offset1 Handover Margin Offset1 (1 db) T2 Time Limit 2 Offset2 Handover Margin Offset2 (2 db) T3 Time Limit 3 ThisHandoverOscillationMinimizationfeatureonlyhassystemconstantstovaryitsworking parameters. No configurable parameter is available for the operator to change. The new recommendation is needed to improve Erab Retainability and to reduce Handover Oscillation events what is important for MOS score and VoLTE performance. Handover Execution may be slightly lower as a drawback of the HO Oscillation Minimization feature activation. The values in braces indicate [level, Value, Units, Class]. A3Offset [Cell, 30, db,Global] is not changed.This is an offsetadded tothe serving cell makingthe serving cell appear better than the neighboring cells. HysteresisA3 [Cell, 10, db, Global] is changed from 10, 30 to 10 and permission is changed to Global.This is an additional hysteresis added to make the neighbor appear worse than the serving cells. TimeToTriggerA3 [Cell, 80, ms, Global] is changed from 80, 320, 512 to 80 and permission is changed to Global. This is the time delay to start sending measurement report after event A3 is triggered. FeatureStateHoOscCtrlUE[Cell,1,,Global]ischangedfrom0to1(DeactivatetoActivate)and permission is Global. This activates / deactivates the Handover Oscillation Minimization Feature. ServiceStateHoOscCtrlUE[Cell,1,,Global]ischangedfrom0to1(InoperabletoOperable)and permission is Global. This makes the Handover Oscillation Minimization Feature operable or not. Parameter Table :

The following KPIs need to be closely monitored by the market once the change is made: Data Retainability and Accessibility HO Preparation and Execution Success Rate UL and DL Volume and Throughput Best Cell Evaluation Report HO Oscillation Rate and events FGA26 will have the following impact on these network performance: Erab Retainability Handover Execution Success Rate Handover Oscillation rate and events The study had been conducted in the San Diego, Ft Myers and Tampa, Florida and Birmingham markets. The presentation outlining the results can be found in this link. Implementation of the Change: In the space below, describe in detail how this change is implemented for each system impacted. No action needed from the markets, these changes will be implemented by the MNT team. For any questionsregardingthetimelineforspecificmarketpleasecontactChristopherWyatt (cw7534@att.com).