A survey on control separation techniques in multi-radio multi-channel MAC protocols <s> E. Hybrid Common Control Channel Techniques <s> In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well. <s> BIB001 </s> A survey on control separation techniques in multi-radio multi-channel MAC protocols <s> E. Hybrid Common Control Channel Techniques <s> In legacy wireless communication systems, spectrum allocation is static, resulting in extremely low spectrum utilization. On the other hand, there is little spectrum left for allocation to an increasing number of emerging wireless applications. A promising approach to solving this paradox is opening up most of the spectrum for unlicensed spectrum users in ways that co-exist with legacy users. Following this direction, this paper proposes the dynamic open spectrum sharing (DOSS) MAC protocol. This protocol allows nodes to adaptively select an arbitrary spectrum for the incipient communication subject to spectrum availability. It offers real-time dynamic spectrum allocation and high spectrum utilization without relying on any infrastructure. It also coexists with legacy wireless applications, while avoiding the hidden and exposed terminal problems. We conduct theoretical analysis of the protocol, and study its performance via simulations. In addition, we covers the radio receiver design <s> BIB002 </s> A survey on control separation techniques in multi-radio multi-channel MAC protocols <s> E. Hybrid Common Control Channel Techniques <s> In wireless ad hoc networks, the major quality of service (QoS) concern and challenge in the design and analysis of contention-based medium access control (MAC) protocols is to achieve good throughput and access delay performance in the presence of hidden terminals, which are defined as the terminals out of the radio coverage area of an intended transmitter but within that of the receiver. We propose and analyze in this paper a new dual-channel random access protocol, called "Double Sense Multiple Access" (DSMA), for improving QoS support in wireless ad hoc networks. By separating the transmissions of ready-to-send (RTS) and data packets into two time-slotted channels and by introducing a novel double sense mechanism, DSMA completely solves the hidden terminal problem and can guarantee the success transmission of data packets. By taking into account the most complex network scenario in which all transmitters are hidden terminals with respect to each other, key QoS metrics such as throughput, blocking probability and access delay are derived mathematically for the proposed DSMA protocol. These analytical results are verified by extensive computer simulations. <s> BIB003
From the previous discussion, it is clear that different classes of protocols offer unique advantages in one way or another. Thus, there are many protocols that combine these features and form a new hybrid protocol. For instance, Power Aware Multi-Access protocol with Signalling (PAMAS) BIB001 utilizes a separate control channel for exchanging RTS/CTS. The length of the upcoming transmission is attached in both RTS and CTS, and the neighboring nodes that overhear RTS or CTS messages can therefore go into sleep mode for the duration of the transmission, thus enabling power saving capabilities. Further, an extra busy tone signal is used to ensure the hidden terminal problem will not occur. Zhai et. al. proposed a new dual-channel MAC protocol (DUCHA)  for multi-hop mobile ad hoc network. This protocol utilizes dual-channel for control and data packets, where RTS and CTS are transmitted over control channel. The operation of DUCHA is shown in Figure 1d , from the figure, it has shown that the used of separate control channel allows RTS/CTS to be exchanged at exposed node when the other exposed terminal is transmitting data. As a result, the exposed terminal problems could be resolved, and spatial reuse could be maximized. In addition, DUCHA exploits the use of out-ofband receiver based busy tone to address the hidden terminal problem. Ma et. al. proposed a Cognitive Radio (CR) based Dynamic Open Spectrum Sharing (DOSS) MAC BIB002 , which consists of three operational channels: a busy tone channel, a control channel, and a data channel. DOSS enables CR devices to identify and negotiate potential data band through the common control channel, and then send data through the continuous fraction of the data band in which both sender and receiver agree. Moreover, the hidden and exposed terminal problem can be alleviated by raising the busy-tone signal in the busy-tone channel. Comparably, Yang et. al. BIB003 design a "Double Sense Multiple Access" (DSMA) scheme based on DBTMA and separate RTS/CTS control. DSMA maintains two out-of-band busy tone, one control channel for RTS/CTS, and one for data transmission. Yang et. al. have identified the problems that the busy tones can not specify the source of busy tone; the collision may occur as multiple senders have sensed the busy-tone and transmitting data at same time. Thus, DSMA employs an additional double sense mechanism which senses the receive-busy-tone prior and after the completion of RTS in order to ensure the authenticity of the busy tone. The node must ensure the receive-busy-tone only appears in second sense, otherwise, the receive-busy-tone could be reserved for some other nodes. In this way, no packet collision in data channel can be guaranteed.