06 RA41216EN40GLA0 Admission Control

Admission Control LTE Radio Parameters RL40

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Contents 1. LTE Functionalities & Features Overview 2. Parameters Structure & SIBs 3. Physical Channel Configuration & Random Access 4. UE State Handling 5. Bearer Management 6. Admission Control 7. Power Control & Power Setting 8. Adaptive Modulation & Coding 9. MIMO Mode Control 10. Idle Mode Mobility 11. Connected Mode Mobility 12. Scheduler 13. SON 4

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Index •Task of Radio Admission Control •Admission Control Algorithms and Thresholds

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Radio Admission Control Introduction (1/3) • Scope of RAC is cell level • RAC algorithms controls establishment of – Signaling radio bearer – Data Radio Bearer

• RAC controls number of UE in a cell – Number of established RRC connection per cell – Number of active UEs (users) per cell

• RAC controls number of DRB in a cell – Number of data radio bearers (DRB) – Number of DRB with QCI=1

• RAC controls emergency calls and emergency sessions – Special margin considered for emergency calls – Special margin considered for IMS emergency sessions (RL30)

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DRB: Data Radio Bearer SRB: Signalling Radio Bearer

Radio Admission Control Introduction (2/3) • RAC applies different criteria for call estblishment and Mobility (HO) – offset in terms of number of rrc connections or active users used, etc – aim is to keep the already established sessions active and support user mobility

• RAC interacts with other RRM entities – – – –

Packet Scheduler Mobility management Radio Bearer Management UE State Management

• RAC acts based on events like: – paging – Handover Request – Call establishment request 7

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Radio Admission Control Introduction (3/3) RL40 • Smart Admission Control – Necessity when offering high bit rate services – Configuration of access control threshold per cell simplified for GBR traffic – RAC reacts on measurements and therefore is adapted in a dynamic way – Congestion control function allows more optimistic admission decisions, and the system corrects overbooking situations using preemption according to priorities (Radio)

• ARP based admission Control – Prioritize the availability of different services  Lower availability services may be offered without jeopardizing higher available services  ‘Must’ availability services like emergency sessions need no dedicated (reserved) resource – Dynamic adaptation of resources to actual need 8

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Service management High RB requests with congestion control by using of priority and smart admissions Rejected UE requests due of too high RB utilization  Only for QCI 2-4 S-RAC  Not for VoIP

Descriptions / Objective: To admit or to reject the requests for esta0blishment of Radio Bearers (RB) on a cell basis Based on number of RRC connections and number of active users per cell and allocation and retention priority (ARP)

ARP = Allocation and retention/maintenance Priority

Smart Admission control

• S-RAC only for GBR traffic

to avoid congestion on ‘guaranteed’ resources • Counter based RAC will not work in case of serving high bit rate users  Replaced by a measurement based function • S-RAC predicts load required/caused by each new GBR radio bearer – Reflecting requested transmission rates in UL/DL under given radio conditions – Considering existing GBR load

• S-RAC offers congestion handling when overbooking of resources is detected e.g. – Radio conditions of high bit rate users getting worse – Too optimistic admission was done – Bursting traffic cannot be served over time.

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Index •Task of Radio Admission Control •Admission Control Algorithms and Thresholds

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Radio Admission Control • RL20 RAC checks against operator configurable thresholds – on Call Establishment:     

max_number_of_rrc_connection max_number_of_rrc_connection_emergency_calls (LTE22 supported) max_number_of_active_users max_number_of_active_DRB (LTE7 supported) max_number_of_QCI1_DRB (LTE10 supported)

– on Intra-Frequency (incoming) Handover:  additional offsets can be defined for • time critical handover (event A5) • handover desired for radio reasons (event A3)  „all or nothing“ – SRB && DRB must be admitted in target cell

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LTE7: Support of multiple EPS bearers LTE10: Conversational Voice LTE22: Emergency Call Handling

RL20 Admission of SRB1 •

RAC compares the number of currently allocated RRC connections in the cell against following parameter: Name maxNumRrc

(LNCEL)

Range 0...840, step 1

Default 240 (420)*

Description Maximum number of UEs in the cell with an established RRC connection. Note*: min(ulChBw,dlChBW) is set to value '20 MHz'

• Admission Control criteria for Signalling Bearer: Number of currently established RRC connections < maxNumRrc

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Admission of SRB1 if min(ulChBw,dlChBw) has value ' 5MHz' and '10 MHz' - maxNumRrc value range is restricted to 0...480 (default value 240) - maxNumRrc+max(addAUeRrHo, addAUeTcHo)