How operators can differentiate through policies when sharing small cells

Transcription

1 How operators can differentiate through policies when sharing small cells Ilaria Malanchini, Markus Gruber (Bell Labs Alcatel-Lucent Germany) May 11,

2 Wireless resource sharing in Europe 1 ST STEP Passive Sharing & National Roaming Agreements SHARING AGREEMENTS IN EUROPE 2 ND STEP Active RAN Sharing Stuttgart 3 RD STEP Active Spectrum Sharing [1] Mobile Infrastructure Sharing, GSMA report, Sept [2] Report infrastructure and spectrum sharing in mobile/wireless networks, BEREC-RSPG report S H ARING IS ALREADY A REALITY! BUT 2

3 Multi-operator integration: FLEXIBILITY? Legacy case: Sharing of physical resources Human negotiation process may take months New sharing agreement Multi-operator equipment Operator X introduces a service innovation the requirements change and the resource share needs to be adapted Needed: Sharing of virtual resources Optimizer Immediate response New slicing of resources OPERATO RS N E E D MORE FLEXIBILITY 3

4 Multi-operator integration: DIFFERENTIATION? Legacy case: Hierarchy of operators Hosting operator is the only one who can change network parameters Technical differentiation is difficult Multi-operator equipment How should parameters that affect all involved operators be set? Need for Virtual network management Technical differentiation is possible All operators manage their own logical network OPERATO RS N E E D MEANS F O R DIFFERENTATION 4

5 Contribution In this work, we show that operators can actually differentiate even when they have to take joint decisions (when actively share small cells) Operator 1 Operator 2 The idea is to base the sharing agreement not on a fixed resource sharing ratio, but to allow deviations and use a flexible sharing ratio F 1 f 1 f 1 F 2 f 2 f 2 Baseline sharing ratio Effective sharing ratio 5

6 System model We assume an HetNets scenario with B macro base stations and S small cells per sector, served by N operators: Macro base stations: macro site is shared but each operator has its own equipment Small cell base stations: equipment, thus capacity, is shared according to a baseline sharing ratio, that we call F n, but deviations are allowed We assume operators have different policies: Operator 1 Operator 2 Increase QoS* + High QoS required High investment cost Decrease OPEX + Low investment cost Low QoS * = low drop/admission probability 6

7 Policy based resource repartition We assume that each operator independently decides on its policies and map these policies into an operator specific parameters, T We exemplarily choose this parameter to be the over-provisioning factor High over-provisioning factor: high QoS and high OPEX Low over-provisioning factor: low QoS and low OPEX 7

8 Overprovisioning Factor Over-provisioning factor vs. load Assuming only the macro is used, then the over-provisioning factor is: OK for night hours maximum load macro current load macro Peak hours: operators policies with only macro is not satisfied, therefore operators offload on small cells Threshold Op 1 Threshold Op 2 Only Macro 2 maximum load small cell number of active small cells effective sharing ratio Traffic Value 8

9 Dynamic sharing mechanism Shared small cells are activated only when needed (e.g. for energy purposes) Since operators have different policies, they need a new small cell to be activated for different values of traffic load (activation point) Therefore using a baseline (fixed) sharing ratio brings to unused resources on the small cells as well as more energy required The idea is that whenever one operator has reached its activation point, there might be at least another operator who is still above its over-provisioning constraint. Therefore, a dynamic sharing of the resources, deviating from the agreed baseline sharing ratio without violating the policy constraints of any operator, can be applied, such that the activation point is delayed (delay in terms of traffic load). We refer to such areas in which a dynamic sharing could bring benefits as critical areas. 9

10 Dynamic resource repartition problem Formulation VARIABLES Variables One integer variable N+1 continuous variables Objective function FORMULATION the formulation minimizes the number of activated small cells as well as the maximum resource reduction The constrains are: The sum of resources for every small cells does not exceed the availability Over-provisioning threshold is not violated Variable ε is equal to the maximum resource reduction 10

11 Numerical results N=2 operators S=4 small cells Macro capacity Λ M = 4.25 Small cell capacity Λ S = Small cell ON Macro Small cell OFF Baseline sharing ratios: F 1 = 0.5 = 0.5 Over-provisioning factors: T 1 = 2, T 2 = 1.75 When small cells are on, they serve 2/3 of the total traffic FTP connections File of 2MByte 11

12 Baseline solution With the baseline solution: - no differentiation - resource/energy wasting 12

13 Proposed mechanism Using the proposed mechanism: - differentiation - no resource wasting Activation points can be analytically derived 13

14 Realistic traffic profile Dynamic a n d f l exible adaptation o f the sharing ra t i o 14

15 Realistic traffic profile S a v i n g i n t erms of active small cells a n d energy consumption 15

16 Summary In this work, we have proposed a dynamic resource sharing scheme that allows operators to differentiate when sharing small cells Operator 1 Operator 2 The mechanism flexibly deviates from the agreed baseline sharing ratio in a mutually beneficial way, taking into account operators policies and minimizing the average number of activated small cells This work shows how multi-operator SON (self-optimizing networks) is feasible and how multiple operators have the freedom to enforce their respective policies This opens up new opportunities for sharing in a regulatory environment where the lack of differentiation and competition remains a major obstacle to network sharing deals f 1 f 2 f 1 f 2 16

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