Wireless Ad Hoc and Sensor Networks

Admission Controller Design for High-Speed Networks 151UserSSSBw 1 (k)NetworkBufferSrMx(k + 1)− +x(k + 1)f (x(k))Adaptive z −1algorithmz −1x d CLR(a)t dSwitch 1Switch 2FIGURE 4.2(a) Bandwidth allocation scheme at the ingress switch/node, (b) network schematic foradmission control scenario.Consider the buffer dynamics at an ingress node/switch fabric, shownin Figure 4.2a, given in the following formxk ( + 1) = Sat( f( xk ( )) + Tuk ( ) + dk ( ))p(4.1)nwith state xk ( )∈R being the buffer length (or occupancy) at time instantnk, T being the measurement interval, and uk ( )∈R being the source ratethat is determined via feedback. The nonlinear function, f( x( k)), is a functionof buffer occupancy, source rate, and service capacity, S r , at the ingressswitch/node, which is given as f (.) = [ xk ( ) −qt ( − T fb) + I ( k) − S k ; isni r )] I ni( k)the packet arrival rate, qt ( − T fb)is the bottleneck queue level, T fb is thepropagation time from the bottleneck to the destination and back to thesource, is the service rate at the outgoing link at the ingress node,S r