mac protocols for wideband wireless local access

... Trang 1Wireless NetworksLecture 35 MAC Protocols for WSN Part II Dr Ghalib A Shah Trang 2Outlines  Challenges in WSNs.  Attributes of MAC Protocol  Overview of MAC protocols  Energy ... Contention-based protocols ► CSMA — Carrier Sense Multiple Access • Ethernet • Not enough for wireless (collision at receiver) ► MACA — Multiple Access w/ Collision Avoidance • RTS/CTS for hidden terminal ... RTS/CTS/DATA Overview of MAC protocols Hidden terminal: A is hidden from C’s CS Trang 9Overview of MAC Protocols Contention-based protocols (contd.) ► MACAW — improved over MACA • RTS/CTS/DATA/ACK

Ngày tải lên: 05/07/2022, 13:25

... energy-efficient MAC protocols: asynchronous MAC (A-MAC) protocol and asynchronous schedule-based MAC (ASMAC) protocol A-MAC and ASMAC protocols are attractive due to their suitabilities for multihop ... uncertain prob-lems, we propose two energy-efficient MAC protocols for WSNs: asynchronous MAC (A-MAC) protocol and asyn-chronous schedule-based MAC (ASMAC) protocol Our timing-rescheduling scheme and ... AND PRELIMINARIES 2.1 Energy-efficient MAC protocols In contrast to typical MAC protocols of WLAN, MAC proto-cols designed for WSNs usually trade off performance (such as latency, throughput,

Ngày tải lên: 22/06/2014, 22:20

... Token-coordinated random access MAC (TMAC) scheme, a scalable MAC framework for wireless LANs TMAC is motivated by two technology and deployment trends First, the next-generation wireless data networks ... 40 TMAC ASM TMACOAR DCF MAC OAR MAC Number of stations (a) Network throughput at 54 Mb/s link capacity Number of stations 15 45 75 105 135 165 195 225 255 285 315 TMACASM TMACOAR DCF MAC OAR MAC ... has been a key design requirement for both the wired Internet and wireless networks In the context of medium access control (MAC) protocol, a desirable wireless MAC solution should scale to both

Ngày tải lên: 22/06/2014, 19:20

... authentifi cation protocol framework HMAC_KEY_D HMAC Key for the Downlink Used for authenticating messages in the downlink direction HMAC_KEY_U HMAC Key for the Uplink Used for authenticating messages ... to use wireless access networks, which were initially proposed for Local Area Networks (LANs) but can also be used for wide area networks 1.2 Wireless Networks and Broadband Wireless Access (BWA) ... Interoperability for Microwave Access) Forum (www.wimaxforum.org) was created in June 2001 with the objective that the WiMAX Forum plays exactly the same role for IEEE 802.16 as WiFi for 802.11 The WiMAX Forum

Ngày tải lên: 27/06/2014, 08:20

... used for authenticating messages in the uplink direction. As for PKMv1, the PKMv2 MAC message for the uplink is C/HMAC_KEY_U and the MAC message for the downlink is C/HMAC_KEY_D HMAC_KEY_D and HMAC_KEY_U ... uses HMAC_KEY_D and HMAC_KEY_U for the following:• Verify the HMAC-Digest attributes in Key Request MAC management messages received from that SS, using HMAC_KEY_U. • Calculate, using HMAC_KEY_D, ... an entire MAC management message with the exception of the HMAC-Digest or HMAC Tuple attributes.15.4.1 Message Authentication Keys The authentication keys used for the calculation of HMAC keyed

Ngày tải lên: 14/08/2014, 09:21

... more b/s/Hz, greater lation symbols can be used For example, QPSK considers two-bit modulation symbols modu-WiMAX: Technology for Broadband Wireless Access Loutfi Nuaymi © 2007 John Wiley & ... often presented as the best performing transmission technique used for wireless systems 5.2.1 Basic Principle: Use the IFFT Operator The FFT is the Fast Fourier Transform operator This is a matrix ... OFDM Principle for Multiple Access The OFDM transmission mode was originally designed for a single signal transmission Thus, in order to have multiple user transmissions, a multiple access scheme

Ngày tải lên: 14/08/2014, 09:22

... provides any transformation or mapping of external network data received through the CS Service Access Point (SAP) into MAC SDUs received by the MAC Common Part Sublayer (CPS) through the MAC SAP (see ... tional FEC for OFDM and OFDMA PHY For OFDMA PHY, the CTC can be used for the support of the optional Hybrid ARQ (HARQ, see Chapter 8) According to mobile WiMAX profi les, the CTC is mandatory for OFDMA ... standard [1] for some test conditions These SNR thresholds are for a BER, Bit-Error Rate, measured after the FEC, that is smaller than 10–6 Trang 13Part ThreeWiMAX Multiple Access (MAC Layer)

Ngày tải lên: 14/08/2014, 09:22

... header format without payload Type II, the header is changed with regard to Type I It is used for some feedbacks specifi c to OFDMA (MIMO, etc) No Payload MAC Header Figure 8.4 Header format ... [2].) Table 8.3 Some fi elds of the MAC header without payload Type I (Based on Reference [2].) HT 1 Header Type One for the header without payload EC 1 For a MAC header without payload, this bit ... Header Check Sequence (same as for the generic MAC header) Table 8.4 Header format without payload Type I use (Based on Reference [2].) Type fi eld (3 bits) MAC header type (with HT/EC
0b10)

Ngày tải lên: 14/08/2014, 09:22

... Access Grant-request The BS decides transmissions in the uplink and the downlink For uplink access, a grant is defi ned as the right for an SS to transmit during a certain duration Requests for ... allow vendors to optimise system performance by using different combinations of these bandwidth allocation techniques while WiMAX: Technology for Broadband Wireless Access Loutfi Nuaymi © 2007 John ... allo-cated bandwidth is specifi cally for the purpose of making bandwidth requests Some CIDs are reserved for multicast groups and for broadcast messages (see Table 7.1) As for individual (unicast) polling,

Ngày tải lên: 14/08/2014, 09:22

... the UL-MAP MAC management message Figure 11.12 shows the BS scheduler operation for the uplink The BS scheduler also decides for the downlink and transmits the decision using the DL-MAP MAC management ... the nrtPS mechanism op-11.3.5 Best Effort (BE) The BE service is designed to support data streams for which no minimum service guarantees are required and therefore may be handled on a best available ... streams consisting of variable-size data packets for which a minimum data rate is required The standard considers that this would be the case, for example, for an FTP transmission In the nrtPS scheduling

Ngày tải lên: 14/08/2014, 09:22

... Technology for Broadband Wireless Access WiMAX. .. choices made by the WiMAX Forum) have different and complementary benefits 204 WiMAX: Technology for Broadband Wireless Access ... tunnelling for roaming); WiMAX subscriber billing; 214 • WiMAX: Technology for Broadband Wireless Access WiMAX services (Internet access, location-based services, connectivity for ... current channel YES YES NO BS informs associated MS of channel change 192 WiMAX: Technology for Broadband Wireless Access Finally, a similar mechanism can be implemented for other purposes than DFS

Ngày tải lên: 14/08/2014, 09:22

... optional for both the MS and the BS WiMAX: Technology for Broadband Wireless Access Loutfi Nuaymi © 2007 John Wiley & Sons, Ltd ISBN: 0-470-02808-4 Trang 2220 WiMAX: Technology for Broadband Wireless ... of a handover • Active BS An active BS is informed of the MS capabilities, security parameters, service fl ows and full MAC context information For a Macro Diversity HandOver (MDHO), the MS transmits/receives ... For MDHO or FBSS supporting MSs, this is a BS where the MS is registered, synchronised, performs ranging and monitors the downlink for control information (see Trang 8226 WiMAX: Technology for

Ngày tải lên: 14/08/2014, 09:22

... OF MEDIUM ACCESS CONTROL TECHNIQUESFOR COOPERATIVE WIRELESS NETWORKS WANG YU NATIONAL UNIVERSITY OF SINGAPORE 2014 Trang 2DESIGN OF MEDIUM ACCESS CONTROL TECHNIQUESFOR COOPERATIVE WIRELESS NETWORKS ... without cooperation CAMMAC Cooperative asynchronous multi-channel medium access control CDMA Code division multiple access CDMAC Coordinated directional medium access control CMDMAC Cooperative multi-channel ... efficient medium access control (MAC) techniques are essential for alltypes of wireless networks, many researchers and engineers are attracted to this field As wireless networks are formed by multiple

Ngày tải lên: 09/09/2015, 09:59

... proposed MAC protocols for UWA networks,and (ii) throughput analysis of MAC protocols For both sections, we shall em-phasize on the research efforts for underwater handshaking-based MAC protocols ... Analysis of MAC Protocols 14 2.2.1 Throughput Analysis of Terrestrial MAC Protocols 14 2.2.2 Throughput Analysis of Underwater MAC Protocols 16 3 A Reference MAC Protocol for UWA Networks ... 8.2.1 Energy-efficiency of MAC Protocols 151 8.2.2 Handling of Node Mobility in MAC Protocols 151 8.2.3 Integration of Routing and MAC Protocols 152 Trang 9Underwater wireless communication

Ngày tải lên: 09/09/2015, 18:49

... 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

... 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