A Non-homogeneous QBD Approach for the Admission and GoS Control in a Multiservice WCDMA System

Abstract

Abstract. We consider a WCDMA system with real time (RT) calls that have dedicated resources, and data non-real-time (NRT) calls that share system capacity. We apply reservation of some resources for the NRT traffic and assume that this traffic is further assigned the resources unused by RT calls. The grade of service (GoS) of RT traffic is also controlled in order to allow for handling more RT calls during congestion periods, at the cost of degraded transmission rates. We consider both the uplink and downlink, and derive performance evaluation results regarding user-perceived QoS parameters, namely the blocking rates of RT calls and sojourn time of NRT calls. On what concerns the bandwidth-sharing policy of NRT traffic, we compare WCDMA behavior in the presence of a high data rate scheme. Finally, we extend our results to cover NRT admission control schemes and examine blocking behavior and transfer times of NRT traffic.

On the WiMAX and HSDPA Coexistence

“…The LDQBD Finite Algorithm (see [11]) cannot be used here to solve eqns. (3) and (4) because it requires strong invertibility conditions on the blocks of Q.…”

On the ergodicity of a class of level-dependent quasi-birth-and-death processes

“…It is possible to construct a convergent K from the elements of K that satisfies (22). Indeed, due to Assumption 1, each A (i) k for k = 0, 1, 2 converges element-wise, thereby ensuring the existence of some N ≥ N * such that (22) holds for the convergent sequence…”

“…While the AQTMC analyzed in [21] is more general, they provide only sufficient conditions for ergodicity and non-ergodicity of these types of chains. Koukoutsidis, Altman, and Kelif [22] devised a non-homogeneous QBD model for admission control of a WCDMA system. They conjectured an ergodicity condition for the case in which the blocks of the infinitesimal generator matrix converge asymptotically to those of a homogeneous QBD process.…”

On the Cooperation Between 3G and 2G Systems

“…see [6]) in which the powers in the interfering cells equal the instantaneous power in the target cell, here we consider that such an equality holds only for the mean power and it is independent of the instantaneous fluctuations of P tot,0 . Here the total power of the base station l can be written as P tot,l =χ U P max , wherē χ U is the average load in a typical cell of the system and P max is the maximal transmission power.…”

“…Thus, using eqn. (6) and knowing the number of calls in the cell, one finds the following expression of the 3G load:…”