Resource allocation for multiple classes of DS-CDMA traffic

Abstract

We consider a packet data direct-sequence code-division multiple-access (DS-CDMA) system which supports integrated services. The services are partitioned into different traffic classes according to information rate (bandwidth) and quality of service (QoS) requirements. Given sufficient bandwidth, QoS requirements can be satisfied by an appropriate assignment of transmitted power and processing gain to users in each class. The effect of this assignment is analyzed for both a single class of data users and two classes of voice and data users. For a single class of data users, we examine the relationship between average delay and processing gain, assuming that ARQ with forward error correction is used to guarantee reliability. The only channel impairment considered is interference, which is modeled as Gaussian noise. A fixed user population is assumed and two models for generation of data packets are considered: 1) each user generates a new packet as soon as the preceding packet is successfully delivered and 2) each user generates packets according to a Poisson process. In each case, the packets enter a buffer which is emptied at the symbol rate. For the second traffic model, lowering the processing gain below a threshold can produce multiple operating points, one of which corresponds to infinite delay. The choice of processing gain which minimizes average delay in that case is the smallest processing gain at which multiple operating points are avoided. Two classes of users (voice/data and two data classes) are then considered. Numerical examples are presented which illustrate the increase in the two-dimensional (2-D) capacity region achievable by optimizing the assignment of powers and processing gains to each class.Index Terms-DS-CDMA, integrated voice and data, power control, resource allocation.

Effect of Load Matrix Method in Removing the Interference in Inter and Intra Cellular Wireless Networks

“…On the reverse link, the participating base stations forward the received data to the serving RNC to combine. [12] In interference limited systems, the uplink capacity is limited by the total transmitted power at the base station and this power was limited by uplink capacity. Inter cell interference calculation is done by multiplying the number of users in a cell by the average interference offered in this cell, this kind of calculation, being suitable for real-time interference simulations based on the number of users, their path loss, slow fading, and the cell area.…”

Optimum Uplink Power/Rate Control for Minimum Delay in CDMA Networks

“…where L/R is the transmission time for a packet when there is no retransmission and we neglect the propagation and processing delay which is negligible compared to L/R [7], [8]. Assuming a stop-and-wait automatic request control for simplicity and an identical packet error probability during the retransmission of a packet, n follows a geometric distribution as ( ).…”

“…The authors in [7] examined the relationship between the average delay and processing gain and searched for the optimum processing gain, i.e., the optimum data rate, in order to minimize the average delay. They assumed that channel gain is time invariant and did not optimize the transmission power.…”

Resource Allocation Technique Using Load Matrix Method in Wireless Cellular Systems

“…On the reverse link, the participating base stations forward the received data to the serving RNC to combine. [12] In interference limited systems, the uplink capacity is limited by the total transmitted power at the base station and this power was limited by uplink capacity. Intercell interference calculation is done by multiplying the number of users in a cell by the average interference offered in this cell, this kind of calculation, being suitable for real-time interference simulations based on the number of users, their path loss, slow fading, and the cell area.…”