mac protocols for wideband wireless local access

... adopted in recent wireless networks design [8] It is possible to classify medium access protocols into two classes [9]: (i) scheduled access, (ii) on demand or unscheduled access The former mechanism ... approaches have been proposed for addressing the drawbacks of the original IEEE 802.11 MAC in the presence of directional antennas, as directional MAC (DMAC) [10] or multihop MAC (MMAC) [11] to mention ... Krishnamachari, and C S Raghavendra, “An adaptive energy-efficient and low-latency MAC for data gathering in sensor networks,” in Proceedings of International Workshop on Algorithms for Wireless, ...

Ngày tải lên: 22/06/2014, 19:20

... proposed schemes only consider the MAC layer performance, that is, throughput The effect of MAC for information retrieval on information processing is analyzed in [7, 8] for infinite and finite sensor ... stores its local measurement along with its location information in the form of a packet for future data collection 2.3 The multiple -access channel When the mobile access point is ready for data ... channel, some form of MAC is needed In this paper, we propose and discuss four MAC protocols, with different performance and complexity trade-off, to optimize the reconstruction performance In each...

Ngày tải lên: 23/06/2014, 00:20

... MAC protocols for wireless ad-hoc networks and also energy-efficient MAC protocols for WSNs Chapter presents the design and evaluation of our traffic-adaptive multi-channel MAC protocol for wireless ... Energy-Efficient MAC Protocols for WSNs This section surveys several MAC protocols for WSNs and highlights their design and limitations We choose to focus on synchronized duty-cycle MAC protocol for its ... 802.11 MAC protocol to better understand and appreciate its basic design when used in wireless networks We then survey existing multi-channel MAC protocols for wireless ad-hoc network for increased...

Ngày tải lên: 10/11/2015, 11:29

... platform for broadband wireless packet access Therefore, the design of a new air interface for broadband wireless packet access has to take into account the fact that the dominant load in the wireless ... Interface for Broadband Wireless Packet Access Broadband wireless packet access should deliver much higher data transmission rates and provide more diverse services than current 2-3G systems All-IP wireless ... Multiplexing WBAN: Wireless Body Area Network WLAN: Wireless Local Area Network WPAN: Wireless Personal Area Network WUSB: Wireless Universal Serial Bus IX LIST OF FIGURES FIGURE 1-1 ITU-R VISION FOR 4G/B3G...

Ngày tải lên: 12/09/2015, 08:18

... WORKS AND PRELIMINARIES 2.1 Energy-efficient MAC protocols In contrast to typical MAC protocols of WLAN, MAC protocols designed for WSNs usually trade off performance (such as latency, throughput, fairness) ... rate (ms/s) 0.45 0.5 ASMAC S -MAC TRAMA A -MAC S -MAC (a) (b) Figure 13: Energy utilization for (a) A -MAC and (b) ASMAC Table 3: Physical layer parameters Ww 32 Ww max 1024 MAC header 34 bytes ACK ... Average clock-drift rate (ms/s) ASMAC S -MAC TRAMA A -MAC S -MAC (a) (b) Figure 15: Waiting time for (a) A -MAC and (b) ASMAC Saving energy is one of the main aims of A -MAC However, we should not achieve...

Ngày tải lên: 22/06/2014, 22:20

... Multiple Access Protocols 3.4.2 Medium Access Control in CDMA 3.4.3 Conflict-free or Contention-based Access? 3.5 Review of Contention-based Multiple Access Protocols 3.5.1 Random Access Protocols: ... Multiple Access 3.5.4 Impact of Capture on Random Access Protocols 3.5.5 Random Access with CDMA 3.5.6 Protocols based on some Form of Channel Sensing 3.5.7 Channel Sensing with CDMA 3.5.8 A Case for ... MULTIPLE ACCESS PROTOCOLS FOR MOBILE COMMUNICATIONS Multiple Access Protocols for Mobile Communications GPRS, UMTS and Beyond Alex Brand Swisscom...

Ngày tải lên: 02/03/2013, 16:59

... triple-duplicate ACKs for the provider and the client is almost twice as that for the other non-compliant STA Therefore, b 0 should be set to (Nci − Npj )/2Nci 3.4 Adjusting algorithm for b We discussed ... the corresponding server for the provider and the client is large enough not to limit throughputs for them We also idealize wireless channels to make our discussion simple For instance, when an ... ICN 2008, 72–77 (Apr 2008) 11 P Liu, Z Tao, S Narayanan, T Korakis, S Panwar, CoopMAC: a cooperative MAC for wireless LAN IEEE J Sel Areas Commun 25(2), 340–354 (2007) 12 P Bahl, R Chandra, P...

Ngày tải lên: 21/06/2014, 01:20

... 802.15.4 MAC in 43.31% for a payload length packet of 50 bytes; (iii) BSN -MAC outperforms IEEE 802.15.4 MAC in 7.20% for payload length packet of 80 bytes; (iv) DQ -MAC outperforms IEEE 802.15.4 MAC ... shown for a traffic load of 80% (i.e., high-density area) It can be seen that (i) BSN -MAC outperforms IEEE 802.15.4 MAC in 19.09% for payload length packet of 50 bytes; (ii) DQ -MAC outperforms ... as S -MAC [8], T -MAC [9], B -MAC [10], X -MAC [11], and MFP -MAC [12] are not energy-efficient enough for real-time monitoring applications in BSNs On the other hand, the problem with TDMA-based protocols...

Ngày tải lên: 21/06/2014, 11:20

... WG, “IEEE Std 802.11e-2005: Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,” ... EWC, “HT MAC Specification, Interoperability MAC Specification v1.24,” Enhanced Wireless Consortium Std., January 2006 [6] IEEE 802.11 WG, “IEEE P802.11n/D3.00: Part 11: Wireless LAN Medium Access ... Since each information bit is encoded into two symbols with bits individually, a total of 14 bits will be required for the encoding process Therefore, the average BER Pe (mn ) in MAC layer can...

Ngày tải lên: 21/06/2014, 17:20

... RF Synthesizer for 802.11a Wireless LAN,” IEEE Journal of SolidState Circuits, vol 38, no 10, pp 1767–1770, 2003 [12] IEEE 802.11, “Part11: Wireless LAN Medium Access Control (MAC) and Physical ... analysis of the IEEE 802.11 MAC layer handoff process,” ACM SIGCOMM Computer Communication Review, vol 33, pp 93– 102, 2003 [9] IEEE 802.11k, Wireless Medium Access Control (MAC) and Physical Layer ... share the AP’s information to reduce the overall scanning delay Our approach may be even more favorable for 802.11 a than for 802.11 b, since the scanning delay will be even higher for 802.11 a with...

Ngày tải lên: 21/06/2014, 17:20

... media access control (MAC) protocol to handle proper management of media access can considerably improve the performance of such a network Power consumption and delay are major concerns for MAC protocols ... cycle MACs A fixed duty cycle MAC uses fixed length period Some of the earliest MAC protocols (e.g., S -MAC [7]) are based on the fixed duty cycle concept In adaptive duty cycling MACs such as T -MAC ... Synchronous duty cycle MACs − Asynchronous duty cycle MACs Synchronous MACs need time synchronization before data communication while asynchronous MACs such as B -MAC [10], X -MAC [11] are independent...

Ngày tải lên: 21/06/2014, 17:20

... the SNAPdMac protocol with χ = 0.1 (SNAPdMac 01Coll50) performs best till around 37 seconds; however, later it performs worse than the SNAPdMac protocol with the χ equal to 0.3 (SNAPdMac 03Coll50), ... simulation run, the SNAPdMac protocol with ζ = (32SNAPdMac) receives more packets and it lives a bit longer than the SNAPdMac protocol with ζ = (21SNAPdMac) Analyzing the SNAPdMac performance against ... protocol, and SNAPdMac protocol The tuning of the SNAPdMac protocol has been investigated as can be observed in the figure The SNAPdMac Coll25 and SNAPdMac Coll35 represent SNAPdMac with RatioCollTHR...

Ngày tải lên: 21/06/2014, 22:20

... throughput We assume the same P for all nodes Throughput performance of the aforementioned models for Channel MAC is presented in Figure The results are shown for a different numbers of node pairs ... throughput for both Channel MAC and IEEE 802.11 With the number of nodes, the received throughput increases rapidly in Channel MAC as compared to IEEE 802.11 For n = 10, Channel MAC outperforms IEEE ... a single-hop scenario, Channel MAC outperforms IEEE 802.11 for all values of P and all numbers of nodes It can be noted that for higher numbers of nodes, Channel MAC achieves higher throughput...

Ngày tải lên: 21/06/2014, 22:20

... performance analysis, the throughputs of the BMMM protocol and our proposed MAC protocol are derived Numerical examples show that our proposed MAC protocol increases the multicast MAC performance ... data frame For reliable multicast MAC transmissions, the proposed MAC protocol replaces the PCF protocol during CFPs (Contention-Free Periods) We can refer to [10] for the method for the AP’s ... (3) The mean of Y can be numerically calculated as Performance Analysis For the analytical performance analysis for our reliable multicast MAC protocol, the following parameters are defined: (i)...

Ngày tải lên: 21/06/2014, 23:20

... the same RF bands among wireless users that operates different wireless systems, instead of supporting homogeneous wireless stations in the same RF bands Therefore, spectrum access scheduling brings ... extensively used and studied, for example, MACA, MACAW [38], IEEE 802.11 DCF [39], PAMAS [40]; and (2) scheduled channel access scheme, such as FDMA, TDMA, CDMA mechanisms in wireless cellular networks, ... structure MAC PDU1 · · · MAC PDUn Pad DLFP DL-MAP UL-MAP DCD UCD MAC PDUs Downlink structure descriptors Broadcast to all SSs Figure 11: Fixed WiMAX/TDD frame structure and burst information channel access...

Ngày tải lên: 21/06/2014, 23:20

... 802.11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications,” 1997 [2] V Mhatre and K Papagiannaki, “Using smart triggers for improved user performance in 802.11 wireless ... 802.11e Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,” 2005 “IEEE Std 802.11k Wireless ... itself does not mean the AP’s capability information Therefore we propose a MAC layer handoff mechanism for IEEE 802.11 WLAN by using AP’s capability information as a handoff criterion, especially...

Ngày tải lên: 21/06/2014, 23:20

... range and localization accuracy Therefore, there is a need to analyze the impact of these channel limitations on the performance of cooperative localization in indoor WSNs Evaluation of localization ... necessary network density required for effective localization, these stationary nodes can constantly provide ranging/localization information which further improves performance in dense cluttered environments ... a realistic platform in which to analyze the G-CRLB and the localization accuracy in different indoor multipath environments 3.1 INDOOR COOPERATIVE LOCALIZATION BOUNDS Problem formulation Based...

Ngày tải lên: 22/06/2014, 06:20

... transmits at rate ri When TMAC adopts the adaptive batch transmission at the Yuan Yuan et al Table 2: Comparison of TMAC, DCF, and OAR DCF MAC OAR MAC TMACR f =108 TMACR f =54 TMACR f =24 S (Mb/s) 18.41 ... (Mb/s) and fairness index 802.1 1MAC TMAC (R f = 216 Mb/s) TMAC (R f = 108 Mb/s) TMAC (R f = 54 Mb/s) TMAC (R f = 24 Mb/s) 6.649 6.544 6.655 6.542 26.490 0.6246 MAC type 4.251 8.572 12.660 17.795 ... A Farago, A D Myers, V R Syrotiuk, and G V Zaruba, “Meta -MAC protocols: automatic combination of MAC protocols to optimize performance for unknown conditions,” IEEE Journal on Selected Areas in...

Ngày tải lên: 22/06/2014, 19:20

... Hui Tong et al Demodulation Demodulation Beamforming for the 1st path of transponder j Beamforming for the 2nd path of transponder j Beamforming for the 3rd path of transponder j Demodulation ... Processing Beamforming for the 1st path of transponder j Time diversity combining Beamforming for the 3rd path of transponder j Demodulation Time diversity combining Beamforming for the 2nd path ... interference suppression [8] Therefore, it is natural to extend our study from conventional beamforming to LCMV beamforming An important step to perform LCMV beamforming is the estimation of the...

Ngày tải lên: 22/06/2014, 19:20