Báo cáo hóa học: "Research Article Efficient MAC Protocol for Subcarrier-Wise Rate Adaptation over WLAN" potx

... Communications and Networking Volume 2010, Article ID 264838, 9 pages doi:10.1155/2010/264838 Research Article Efficient MAC Protocol for Subcarrier-Wise Rate Adaptation over WL A N Sung Won Kim, 1 Byung-Seo ... the proposed subcarrier-wise rate adaptation) . A sender sends an RTS packet setting Rate subfield in PLCP header to 1111. This informs a receiver the use of t...

Ngày tải lên: 21/06/2014, 17:20

... original IEEE 802.11 MAC in the pres- ence of directional antennas, as directional MAC (DMAC) [10] or multihop MAC (MMAC) [11]tomentionafew, while other solutions have been proposed for scheduled ac- cess, ... offset scheduling (WiseMAC), without an excessive signaling overhead nor re- quiring a strict synchronization as it happens in the S -MAC protocol. According to the STAR MAC...

Ngày tải lên: 22/06/2014, 19:20

... will discuss the scheduling strategies. We will consider different resource fair strategies, throughput fair strategies and QoS strategies targeting a certain bit rate. All derivations are done ... quantitative notion of how much overloaded a cell is and how many users are unsatisfied in fact. So for the QoS case, we will define more appropriate performance metric in the following. 4.2. Overl...

Ngày tải lên: 21/06/2014, 11:20

... shows, even for a very small user pool, for example, K = 5 users, the proposed scheme has a great sum rate advantage over the sum rate of other limited feedback schemes, which are plotted. Sum rate ... the algorithm, user k has all the required information to evaluate the rate of user k s as well as its own rate. Therefore, it will send back a sum rate value, R k = log 2 (1 +...

Ngày tải lên: 21/06/2014, 17:20

... avoid this severe performance loss, frame size adaptive MAC protocols for RFID system were proposed in [11–15]. The frame size adaptive MAC protocol in [11] uses a simple estimate for the tag p opulation ... provide a notable performance improvement over fixed frame size RFID MAC protocols, they may still lead to less than acceptable performance for dense RFID systems. We note...

Ngày tải lên: 22/06/2014, 19:20

... appr.II inference, averaging at 0.0127 for forward pass and 0.0129 for backward. Moreover, the KL divergence of appr.I inference has much more spikes than that of appr.II, both in forward and backward pass. ... solely on appearance information gives a very poor recovering performance. Although the spatiotem- poral information is used, the recovering performance is still unsatisfactory due...

Ngày tải lên: 21/06/2014, 05:20

... Unfortunately, this tweak comes at the cost of reducing the overall dispersion of the structure and exacerbating the notch in the frequency response around the crossover frequency, and, therefore, ... quality. To avoid the overhead associated with an arbitrary change in sampling rate, it is best to downsample to a rate which is an integer division of the main sampling rate, rather than do...

Ngày tải lên: 21/06/2014, 05:20

... obtained bit error rate (BER) versus signal-to-noise ratio (SNR) performance curves. The BER performance results depicted are obtained by taking the average of the BER curves over 10 4 independent channels. ... proposed a low-training overhead equalizer for the general case of frequency selective transmitter and receiver IQ imbalance together with CFO and channel distortion for single...

Ngày tải lên: 21/06/2014, 08:20

... study adopts hash message authentication code (HMAC) functions to generate HMAC(data) and aggregate HMAC(data) with original multicast data as [data |HMAC(data)]. Secure multicast com- munication ... DMHBGKA scheme outperforms other methods in terms of rekeying performances, computation and communication costs, and overhead. Importantly, the proposed schemes are efficient and scalable for num...

Ngày tải lên: 21/06/2014, 11:20

... proactive protocols outperform better [2]. In this work, we use certain elements of the Optimized Link State Routing protocol (OLSR) [3], which is one of the four basic protocols adopted for MANETs. ... relay (mpr) extension for ad hoc networks,” IETF Request for Comments: 5449, February. [9] B. Mans and N. Shrestha, “Performance evaluation of approx- imation algorithms for multipoi...

Ngày tải lên: 21/06/2014, 11:20