A dual-band (2.5 GHz and 5.5 GHz) wireless-LAN chip-set, consists of a RF IC and a BBP/MAC IC with integrated USB 2.0 interface, is presented. Together with external power amplifiers, this chip-set provides the complete solution and meets the IEEE 802.11a/b/g standard specifications. Without using external SAW filters, the system achieves receive sensitivity (54Mbps) of −70 dBm at antenna port, and transmit OFDM error-vector-magnitude better than −28 dB. The active die area of the RF IC and the BBP/MAC IC is 5.4 mm 2 and 17 mm 2 respectively. The complete solution uses few external components and occupies active board area of less than 1100 mm 2 .
Cooperative medium access control (MAC) Protocols make use of the multi-rate capabilities of IEEE 802.11 to achieve higher throughput and shorter delay. This is achieved through transmitting a packet via a helper node by means of a faster twohop links rather than a slower direct one-hop link. The Cooperative MAC protocol [1-3] transmits only one packet from the source node for each successful transmission attempt in the channel. In this paper, we extend this Cooperative MAC protocol such that it is capable of transmitting multiple packets for each successful transmission attempt in the channel in an Ad Hoc Wireless Network. Furthermore, two traffic classes are considered. We call this new proposed MAC protocol as Burst Mode Cooperative MAC. The key idea here is to maximize the successful channel access by transmitting a number of data packets instead of just one data packet as long as the overall data transmission time of multiple packets for the two-hop links is shorter or equal to the slower one-hop data transmission time of multiple packets. This cuts down the channel contention time for transmitting each packet and improves the header-to-payload overheads. Performance metrics like throughput and delay are considered. These performance metrics are evaluated via simulation. Numerical results show that the throughput of the proposed Burst Mode Cooperative MAC can be up to 20% better than that of Cooperative MAC, while the delay is still better than IEEE 802.11b MAC.
An emerging short range wireless personal area network (WPAN) is the IEEE 802.15.3c. It can transmit Gigabits per second. In this paper, an approximate analytical formulation of the saturated throughput of IEEE 802.15.3c MAC in the directional contention access period (D-CAP) in the presence of contention time allocation period (CTAP) is presented. The analytical framework is formulated for N devices, including the pico-net controller (PNC). The state transition diagram is modeled by a two-dimensional discrete-time Markov chain. One dimension of the Markov chain is for the backoff stage and the second dimension is for the value of the backoff counter. The saturated throughput is approximated by the product of a weighted ratio of the throughput of the regular sub-CAP (RS-CAP) and the throughput of the RS-CAP minus the period necessary to transmit a packet before the end of the current RS-CAP, the probability of the number of devices in a beam sector and the number of beam sectors. Numerical results of the saturated throughput corresponding to typical parameter values are presented. These results show the advantage of IEEE 802.15.3c MAC in the D-CAP using the single carrier mode when the number of devices in the WPAN is large.
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