Multi-Channel MAC protocols increase network throughput because multiple data transmissions can take place simultaneously. However, existing Multi-Channel MAC protocols do not take full advantage of the multi-channel environment, because they lack a mechanism allowing wireless stations to acquire vacant channel and time resources. In this paper, we first establish the basic model of existing Multi-Channel MAC protocols to know the capability of the most important existing protocols. Next, under the condition that each station can use only two transceivers, we propose Multi-Channel MAC protocols that effectively utilize idle channels and potentially available time resources of stations by employing bursts and interrupted frame transfers. We assume a transceiver can behave as either a transmitter or a receiver but not both at the same time. Moreover, we show the effectiveness of our proposal by computer simulation. Furthermore, through the evaluation in the case that each station can use more than two transceivers, we confirm two transceivers' case is best solution in terms of both attained throughput and hardware complexity.

The Medium Access Control (MAC) protocol that uses non-overlapping multiple channels, called the multi-channel MAC protocol, was proposed in order to increase the capacity of ad hoc networks. Since the number of packet interfaces on each node is less than the number of channels in ad hoc networks in general, the node needs to select a suitable channel for data transmission. This means that the multi-channel MAC protocol must be provided with a good channel selection algorithm. In this paper, we design a channel selection algorithm called Conditionally Randomized Channel Selection (CRCS) based on Extended Receiver Directed Transmission (xRDT) protocol that only uses one packet interface. Briefly, CRCS uses the acitve channel for data transmission until the amount of data packets reaches a threshold, at which point it selects one of the available channels other than the active channel. Although CRCS is a very simple channel selection algorithm, by using network simulator we find that CRCS is effective to increase the capacity of ad hoc networks and to keep the load balance of all channels compared to the other channel selection algorithms.

The dynamic channel selection mechanism used in existing multi-channel MAC protocols selects an idle data channel based on channel usage information from one-hop neighbor nodes. However, this method can cause multi-channel hidden node problem in multi-hop wireless networks. This letter proposes a new approach to channel selection. Nodes snoop data channels during idle times and then select an idle data channel within the carrier sensing range using both the snooping results and the channel usage information. Our simulation results verify that the proposed channel selection approach can effectively avoid the multi-channel hidden node problem and improve the networkwide performance.

In this paper a multi-channel MAC protocol with dynamic channel allocation (MMAC-DCA) in CDMA Ad Hoc networks is proposed. Under MMAC-DCA, the service sub-channels are dynamically allocated by the RTS/CTS dialogue on the common sub-channel, only when a node has a packet to transmit. In addition, a Markov mode is presented to analyze the performance of MMAC-DCA.