Analysis of Packet Error Probability in Delay Constrained Communication Over Fading Channels

Future wireless networks are expected to provide quality of service (QoS) guarantees. QoS requirements at the networking layers include data rate, delay bound, and packet error probability. However, these QoS requirements pose significant challenges since wireless fading channels may cause severe QoS violations. To mitigate fading effects, adaptive schemes such as transmission rate control and power control are usually used. In this paper, we study a wireless communication system that adapts the transmission rate; we assume that the channel state information (CSI) is available at the transmitter side, and the transmission power is fixed. The system under study consists of 1) a discrete-time queueing system on the link layer, and 2) a channel coding system on the physical layer. The objective of this paper is to analyze the relationship among packet error probability, data rate, delay bound, and buffer size. In our analysis, we consider three types of packet errors, i.e., 1) packet drop due to full buffer, 2) packet drop due to delay bound violation, and 3) packet decoding error due to channel noise. We derive packet drop probability and decoding error probability for our system, and obtain an upper bound on the packet error probability. Furthermore, by minimizing the packet error probability over the transmission rate, we obtain an optimal rate control law that guarantees the user-specified data rate and delay bound. Our results show that our analysis agrees well with simulation.