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This paper proposes a downlink mapping algorithm for two-level requests in Orthogonal Frequency Division Multiple Access based IEEE 802.16e systems under the Adaptive Modulation and Coding (AMC) mode by which the modulation and coding scheme (MCS) of a user may be different for available subchannels. Given a set of requests each with two priorities, the proposed algorithm efficiently allocates a two-dimensional...
The IEEE 802.16e standard, which adopts OFDMA PHY and is generally known as Mobile WiMAX, has grabbed the attention of wireless communication industry for the past few years. It is a technology optimized for IP-based high speed long-distance wireless broadband access. In the downlink of Mobile WiMAX systems, data requests have to be mapped into rectangular regions. Such a constraint results in an...
This paper proposes an efficient downlink resource allocation scheme for Orthogonal Frequency Division Multiple Access based WiMAX systems using the Adaptive Modulation and Coding mode operation. Given a set of user requests, the proposed algorithm determines the modulation scheme and allocates a two-dimensional (time and frequency) burst to each user. It is known that finding the optimal solution...
Piggyback is an effective way to reduce the MAC protocol overhead of wireless networks. This paper considers the physical data rate and transmission bit error to derive the criterion of piggyback. Numerical results show that the improvement of piggyback can reach 40% for some cases. For given the bit error rate and the data rate, we also provide the criterion for every combination in a table.
Channel Utilization is a performance index to measure the protocol efficiency of a WLAN medium access control (MAC). This paper presents a simple method to achieve maximum channel utilization for the IEEE 802.11n using basic Distributed Coordination Function (DCF). We find that the channel utilization only depends on the number of stations for the IEEE 802.11n with a given maximum aggregated frame...
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