Downlink ratio impact on downstream traffic performances on WiMAX

Abstract

Worldwide Interoperability for Microwave Access (WiMAX) offers high speed data transfer with various quality of service (QoS) for different applications. One of the services is the downlink ratio adjustment. Theoretically, the parameter allows users to manage bandwidth for uplink and downlink direction. As there is no related work to proof this parameter adjustment, this paper examines the impact through network simulator for downlink streaming. With limited total capacity of the simulated network, by using 4 nodes with downlink traffics varied from 5 to 15 kbps, simulation proofs that by changing downlink ratio from 0.1 to 0.9, the downlink stream performance is increasing with delay decrement up to 5.34 ms, jitter decrement 9.1 ms and packet loss reduction about 97.62%.

The Impact of Length of Frame on The Performance of Video Application in WiMAX System

“…The upper limits of the overall delay time for video conferencing and the time lag have been calculated through research. As a result, it is extremely sensitive to E2E delay when there is no consensus on the best E2E number for this application [5]. Some sources say that an E2E delay of less than 400msec is acceptable [8], while others say that it should be less than 150msec [11] or less than 100msec [17].…”

“…The packet delay variation was shown in Figure (5). One of the video characteristics is jitter which means the variety in the time of the received packet, it represents the maximum value of jitter in four different frame lengths (5, 10, 15, and 20 msec).…”

“…In general, the conventional approach to providing video conferencing services is based on static video quality, which can result in one of two outcomes: the first saves cell capacity at the expense of video quality, while the second rapidly depletes cell capabilities. In the WiMAX system, the frame length has a considerable impact on video applications [3][4][5]. While guaranteeing that all sent packets arrive, the frame length must be adjusted to ensure that the packet delay Variation time is less than 30 milliseconds and the End-to-End delay is as low as possible.…”

“…There is a tradeoff between the video quality and the resources available. In this paper the influence of frame length on video applications was investigated by examining the effect of four frame lengths (5,10,15, and 20 mSec) on the Packet Delay Variation, End-to-end packet delay, traffic sent and received with modulation type 64QAM and high quality of video conference application are used. The optimal frame length was found to be 10 milliseconds, with the Packet Delay Variation being the smallest, the Packet End-to-End Delay being the shortest, and the number of received packets being equal to the number of sent packets.…”