TKN Telecommunication Networks Group Channel'assignment' in'mul./radio' Wireless'Mesh'Networks Michele'Pi:oni' 12.02.2015 1 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Presenta.on'outline • Introduc.on'and'mo.va.on' • Literature'overview' • In#depth:'“A'Traffic/Aware'Channel'and'Rate'Reassignment' Algorithm'for'Wireless'Mesh'Networks”' • Classifica.on'of'analyzed'works' • Conclusions'and'outlook'on'future'research 2 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Wireless'Mesh'Networks • Mul./hop'rou.ng'through' nodes'of'a'mesh'topology' • Posi.on'of'nodes'is'fixed' • Outdoor'or'indoor' • No'strict'power'constraints' • Mul.ple'radio'interfaces' • Last/mile'Internet'access' • Used'by'enterprises'and' communi.es 3 [*] [3] [*]'h:p:/ /blog.ninux.org/2014/01/18/fishsupernodeborrello/conquista/lunghezza/ 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Mul.ple'radios,'mul.ple'channels 4 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Mul.ple'radios,'mul.ple'channels 4 [*] [*]'Adapted'from'h:ps:/ /commons.wikimedia.org/wiki/File:Sidelobes_en.svg 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Mul.ple'radios,'mul.ple'channels 4 [*] [*]'Adapted'from'h:ps:/ /commons.wikimedia.org/wiki/File:Sidelobes_en.svg 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Mul.ple'radios,'mul.ple'channels 4 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Challenges • Network'par..oning • Channel'dependency'and'ripple'effects • Impact'on'rou.ng • Non–convergence 5 [8] 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Approaches • Centralized'vs.'distributed' • Sta.c'vs.'semi–sta.c'vs.'dynamic' • Joint'rou.ng'vs.'separate'rou.ng' • Load–aware'vs.'load–independent 6 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Literature'.meline • 2004:'Adya'et'al.'[1]'(Mul./radio'unifica.on'protocol)
 ''''''''''Bahl'et'al.'[2]'(SSCH:'Channel'hopping)
 ''''''''''Raniwala'et'al.'[3]'(Centralized'CA'and'rou.ng'[Bonus:'NP/hardness'proof])' • 2005:'Alicherry'et'al.'[4]'(Centralized'CA'and'rou.ng)' • 2007:'Ko'et'al.'[5]'(Distributed'CA)
 ''''''''''Skalli'et'al.'[6]'(MesTiC)' • 2008:'Crichigno'et'al.'[7]'(Survey'paper)' • 2010:'Marina'et'al.'[8]'(Topology'control'approach)' • 2013:'Avallone'et'al.'[9]'(Traffic'aware'reassignment)' • 2014:'Wellons'and'Xue'[10]'(Time'par..oning) 7 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 In#depth 8 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 9 • Sta.c'algorithms'do'not'capture'the'variability'of' traffic'pa:erns'(e.g.'during'different'.mes'of'the'day)' • It'is'necessary'to'adapt'to'varying'demands' • In'doing'so,'the'amount'of'changes'should'be'kept' low'to'avoid'channel'change'penal.es 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Channel'switch'costs • Transceiver'delay
 (~100'µs)' • MAC'layer
 (~2'ms)' • Link'invalida.on
 (e.g.'OLSR:'seconds)' • Routes'may'change' • TCP'RTO'(up'to'60s) 10 Effect'of'channel'switches'on'TCP'throughput'with'OLSR'[9]' 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 11 • Collision'domain'(c.d.)'of'link'l:'set'of'links'which'can' not'transmit'at'the'same'.me'as'l'(on'the'same' channel)' • Total'u5lisa5on'of'a'c.d.:'ra.o'of'flow'rates'over' capacity' • Best'performance'is'obtained'when'u.liza.on'is' below'a'certain'threshold 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 12 • Rate'selec.on'influences'the'u.liza.on'of'a'c.d.' • Lower'rates'mean'frames'take'more'air'.me' • Lower'rates'are'also'less'sensi.ve'to'interference' (demodula.on'is'more'robust) [9] 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 13 • Proposed'algorithm:'Minimum'Varia.on'Channel'and' Rate'Reassignment'Algorithm'(MVCRA:R)' • Reduces'the'total'u.liza.on'(across'all'c.d.)' • with'a'limited'number'of'channel'changes' • leveraging'the'possibility'to'change'rates 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 14 Performance'evalua.on:'repeated'traffic'varia.ons'[9] (20/30'nodes,'2/3'radios'per'node) 

Channel'assignment'in'mul./radio'WMNs A#Traffic0Aware#Channel#and#Rate#Reassignment#Algorithm#for# Wireless#Mesh#Networks''' Avallone,'Di'Stasi,'Kassler'(2013) 12.02.2015 15 Performance'evalua.on:'real'traffic'traces'[9] 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Classifica.on 16 MAC$layer Control$ philosophy Switching Traffic Rou9ng Evalua9on [1] Modified Local Dynamic N/A N/A S R [2] S [5] Standard Distributed Sta.c'arer' convergence Independent Separate R [8] Centralized Sta.c S M [6] Aware S [3] Joint S R [4] S M [10] Semi/sta.c MT [9] Separate ST S:'simula.on,'R:'real'world'experiment,'M:'mathema.cal'evalua.on,'XT:'real'traffic'traces 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Conclusions • Semi/sta.c'approaches'are'recently'emerging' • Adapta.on'to'load'is'important' • Centralized'algorithms'are'considered'more'viable 17 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 Further'research • Meta–analysis'of'different'approaches,'including'a' standardized'performance'evalua.on' • Incorporate'a'redundancy'level'in'CA'algorithms'to' improve'the'robustness' • External'interference–aware'algorithms 18 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 References • [1]'A.'Adya,'P.'Bahl,'J.'Padhye,'A.'Wolman,'and'L.'Zhou,'“A'mul./radio'unifica.on'protocol' for'IEEE'802.11'wireless'networks,”'in'Broadband'Networks,'2004.'BroadNets'2004.' Proceedings.'First'Interna.onal'Conference'on,'2004,'pp.'344–354.' • [2]'P.'Bahl,'R.'Chandra,'and'J.'Dunagan,'“SSCH:'slo:ed'seeded'channel'hopping'for'capacity' improvement'in'IEEE'802.11'ad/hoc'wireless'networks,”'in'Proceedings'of'the'10th'annual' interna.onal'conference'on'Mobile'compu.ng'and'networking,'2004,'pp.'216–230.' • [3]'A.'Raniwala,'K.'Gopalan,'and'T.'Chiueh,'“Centralized'Channel'Assignment'and'Rou.ng' Algorithms'for'Mul./channel'Wireless'Mesh'Networks,”'SIGMOBILE'Mob.'Comput.' Commun.'Rev.,'vol.'8,'no.'2,'pp.'50–65,'Apr.'2004.' • [4]'M.'Alicherry,'R.'Bha.a,'and'L.'(Erran)'Li,'“Joint'Channel'Assignment'and'Rou.ng'for' Throughput'Op.miza.on'in'Mul./radio'Wireless'Mesh'Networks,”'in'Proceedings'of'the' 11th'Annual'Interna.onal'Conference'on'Mobile'Compu.ng'and'Networking,'New'York,' NY,'USA,'2005,'pp.'58–72.' • [5]'B./J.'Ko,'V.'Misra,'J.'Padhye,'and'D.'Rubenstein,'“Distributed'Channel'Assignment'in' Mul./Radio'802.11'Mesh'Networks,”'in'IEEE'Wireless'Communica.ons'and'Networking' Conference,'2007.WCNC'2007,'2007,'pp.'3978–3983. 19 

Channel'assignment'in'mul./radio'WMNs 12.02.2015 References • [6]'H.'Skalli,'S.'Ghosh,'S.'K.'Das,'L.'Lenzini,'and'M.'Con.,'“Channel'Assignment' Strategies'for'Mul.radio'Wireless'Mesh'Networks:'Issues'and'Solu.ons,”'IEEE' Communica.ons'Magazine,'vol.'45,'no.'11,'pp.'86–95,'Nov.'2007.' • [7]'J.'Crichigno,'M./Y.'Wu,'and'W.'Shu,'“Protocols'and'architectures'for'channel' assignment'in'wireless'mesh'networks,”'Ad'Hoc'Networks,'vol.'6,'no.'7,'pp.'1051– 1077,'Sep.'2008.' • [8]'M.'K.'Marina,'S.'R.'Das,'and'A.'P.'Subramanian,'“A'topology'control'approach'for' u.lizing'mul.ple'channels'in'mul./radio'wireless'mesh'networks,”'Computer'Networks,' vol.'54,'no.'2,'pp.'241–256,'Feb.'2010.' • [9]'S.'Avallone,'G.'D.'Stasi,'and'A.'Kassler,'“A'Traffic/Aware'Channel'and'Rate' Reassignment'Algorithm'for'Wireless'Mesh'Networks,”'IEEE'Transac.ons'on'Mobile' Compu.ng,'vol.'12,'no.'7,'pp.'1335–1348,'Jul.'2013.' • [10]'J.'Wellons'and'Y.'Xue,'“The'robust'joint'solu.on'for'channel'assignment'and' rou.ng'for'wireless'mesh'networks'with'.me'par..oning,”'Ad'Hoc'Networks,'vol.'13,' Part'A,'pp.'210–221,'Feb.'2014. 20