Self-Organizing Coalitions for Conflict Evaluation and Resolution in Femtocells
Luis G. U. Garcia, Aalborg UniversityGustavo W. O. da Costa, Aalborg UniversityAndrea F. Cattoni, Aalborg UniversityKlaus I. Pedersen, Nokia Siemens NetworksPreben E. Mogensen, Aalborg University, Nokia Siemens Networks
Outline
Problem and solution overview
Supporting concepts
Coalition formation rules
Conclusions
Simulation scenario and results
Frequency planning / spectrum usage in cellular networks
Large macrocellswith sparseplannedplanned reuse
PastPast CurrentCurrent FutureFuture
Small macrocellswith tightplannedplanned reuse (1)
Heterogeneous networks includinguncoordinateduncoordinatedfemtocell deployment
ProblemProblem:
• Massive number of femtocells planning and optimization is too costly.
• High interference possible due to dense deployment and random HeNB and UE locations.
Proposed SolutionProposed Solution: Dynamic spectrum sharing using carrier aggregation.
Proposed framework
Low load – First-come, First served
High load – SSelf-OOrganizing CCoalitions for CConflict EEvaluation and RResolution (SOCCERSOCCER)
SOCCER in a nutshell
• Distributed dynamic method for spectrum sharing amongst femtocells no need for planning. Self-optimizingSelf-optimizing.
• Measurements determine incoming and outgoing SINR (BIM)• Evaluation of system capacity for different options
(reuse/orthogonal allocation).• Six simplesimple rules for formation of coalitions and
redistribution of resources (component carriers) on efficientefficient and fairfair way.
• Enabler: low capacity HeNB to HeNB communication link, as typically assumed for ACCS.
• Avoid reconfiguration storms: everything solved locally.
Outline
Problem and solution overview
Supporting concepts
Coalition formation rules
Conclusions
Simulation scenario and results
Evaluation of coalitions
)(1)(1)()( BreuseCAreuseCBcoalitionCAcoalitionC
Pair wise evaluation, based on sum system capacity
Strong interference bonding condition
SINRCell A
SINRCell B
Reuse isbetter
Orthogonal is better
Strong Interference Bonding Graph
MaximalClique-3
Clique 2
Maximal clique sizes define the optimal local frequency reuse!Maximal clique sizes define the optimal local frequency reuse!
Outline
Problem and solution overview
Supporting concepts
Coalition formation rules
Conclusions
Simulation scenario and results
Coalition formation rulesA coalition is a bilateral mutual agreement of having
an orthogonal allocation.
New coalitions are formed when HeNB needs more spectrum.
Optimized method for maximal cliques up to size 3 only 6 simple formation rules.
CFR CFA
Coalition formation
Outline
Problem and solution overview
Supporting concepts
Coalition formation rules
Conclusions
Simulation scenario and results
Simulated scenarioDual stripe, 6 floors, 40 apartments per floor *
25% and 75% deployment ratio
* 3GPP RAN 4, “Simulation assumptions and parameters for FDD HeNB
RF requirements,” Tech. Rep. R4-092042, May 2009.
What is the maximal clique distribution on this scenario?
25% deploymentratio
75% deploymentratio
Normalized Throughput at 25% deployment ratio
Normalized Throughput at 75% deployment ratio
Outline
Problem and solution overview
Supporting concepts
Coalition formation rules
Simulation scenario and results
Conclusions
Conclusions
Femtocell deployment should rely on self-organizing spectrum allocation
Proposal • At low traffic load simple threshold based selection.• At high traffic load interference management using
coalitions (SOCCER).
SOCCER has a lot of potential to become practical • Simple • Very effective method• Based on standardized measurements
Applicable to LTE-Advanced as well as other systems