Resource Allocation in Wireless Networks for Multimedia Traffic

Resource Allocation inWireless Networks forMultimedia TrafficAbdullah-Al Mahmood

Resource Allocation Resource in wireless networksChannel / Bandwidth FactorsFairnessDynamic environmentQuality of Service (QoS), particularly formultimedia or real-time traffic2

A Simple Strategy Assumption: multimedia servers controlQoS parameters Mechanism of allocationControl throughput requirementn multimedia objects (flows)ω i = requirement for object iθ i = dropping ratio for object i3

A Simple Strategy (contd.)|O i | = normalized size of object iEnsuring fairness:Minimize ∑ i

Dynamic Requirements Variation of demand in multimedia data Initiation of newuser/object/flow/demand Handoff to/from current cellAdditional consideration Intrinsic characteristics of the wirelesstechnology being used5

Wideband CDMA NetworksSystem Model Frequency Division Duplex DS-CDMA Physical layer similar to W-CDMA for 3G Few random access channels & controlchannels Many dedicated access channels forusers/traffic6

Wideband CDMA Networks Focus: MAC protocol for uplinktransmission Uplink capacity is interference limited,not code-limited Difference with W-CDMAcentralized rate scheduling Uplink channels synchronized at timeslotlevel [T=scheduling period] underdemand-assignment MAC Scheme7

Wideband CDMA Networks8

Capacity of Wideband CDMA Soft (not fixed) Notion of nominal capacityN users Nominal capacity C δ = P U /(P U +I+P n )γ r,i = required/minimum SIR for user I∑ 1≤i≤N γ r,i /(1+ γ r,i ) ≤ C δ9

Resource AllocationCDGPS for Fixed Capacity Assigns weight (not BW) to flows Calculates lower bound of the softcapacity from nominal capacity Uses this bound and service request,expected amount of service andeventually allocated channel rate iscalculated10

Effect of Soft Capacity Choose SIR and allocation rate vectorsfor maximizing throughput over a longperiodAlgorithm Compute requested SIR for all users Determine allocation based on nominalcapacity, weight of flows and requestedSIRS11

C-CDGPS Uses concept of service differentiation Delay-insensitive data is allocated lessresource Credits are considered as well asweights of flows If some flow is denied fair share thencredit is accumulated (bounded by limit)12

Statistical QoS Guarantee inMultipath Fading ChannelHandling Real Time Traffic (SW-CDGPS) Each traffic is assigned constant/staticweight Requested traffic amount is convertedto BW requirement [in terms of SIR] Effort is made for allocating as muchBW as possible iteratively13

Statistical QoS Guarantee inMultipath Fading ChannelNon-real Time Traffic (DW-CDGPS)Weights of flows are adjusted accordingto required fairness bound andmultipath fading parameter14

Possible Research Issues Consider absence of centralized ratescheduler Consider location dependent noise andnon-uniform interference15

Questions?