Mobile Worldwide Interoperability for Microwave Access networks usually provide flexible sleep-mode operations that allow mobile stations to conserve energy during sleep or active mode. For example, the IEEE 802.16e/m standard presents three power-saving classes that can be associated with different types of network connections to decrease the power consumption of mobile stations. However, previous studies failed to fully use the sleep-mode features to save energy of a mobile station while simultaneously maintaining unicast and multicast/broadcast connections. This study proposes an energy-efficient packet scheduling algorithm for both multicast and broadcast services that does not violate the QoS requirements of real-time connections. The proposed activity aggregation selection mechanism approach can minimize total power consumption of mobile stations in one cell and simultaneously satisfy the QoS of real-time connections. This method improves energy efficiency for IEEE 802.16e/m and the activity aggregation selection mechanism approach can optimize sleeping mode features to save the energy of mobile stations with overlapping connection packets The simulations in this study verified the proposed approach.(1) Default listening window: length of the default listening window.(2) Initial sleep cycle: length of the initial sleep cycle.
Because the bandwidth usage of wireless transmission is limited, one of the major research topics in this field is to improve system throughput by supporting multiple users with limited bandwidth resources. Although there are several studies on cross-layer designs for improving system throughput, previous research on quality-of-service guarantee and fairness are relatively rare. This study proposes a cross-layer subcarrier permutation (CLSP) mechanism that uses cross-layer strategies to select suboptimal subcarriers. Service flows simulations in the IEEE 802.16e system indicate that CLSP achieved a lower delay time and a long-term fairness among multiple users. Experimental results further show that the throughput of CLSP is 28 percent higher than that of the partial usage of subchannels model using the orthogonal frequency division multiple access technique.
Adaptive Modulation and Coding (AMC), which is a technology used when channel condition changes, is adapted in Mobile Worldwide Interoperability for Microwave Access (WiMAX). Scalable Video Coding (SVC) is a video coding scheme used for different users with bandwidth level. SVC encodes a video into a number of layers. Users receive different number of encoded layers based on their channel condition. In this paper, Intermediate Control Server (ICS) is proposed to deal with the signaling between multimedia server and BS. Both AMC and SVC are employed to enhance the user perceived video quality in the system
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