In this research, core technologies supporting 3Gbps WLAN will be studied in order to accommodate uncompressed HDTV video and very high throughput applications. For very high throughput, we will develop a contention based directional MAC protocol using circular RTS/CTS in 60GHz bands in order to fully utilize merit of the spatial reuse and to tackle the problems of deafness and hidden node. Examples of applications supporting more than Gbps data rate. Standardization organizations such as IEEE802.11ad and IEEE802.15.3c recommend 60GHz spectrum for very high throughput communication. Although IEEE802.15.3c exploiting reservation based directional antenna is currently being standardized, there are still lots of technical challenges to be improved, e.g., contention based directional MAC is not incorporated in the standard. In this work, we will develop a contention based directional MAC protocol using circular RTS/CTS in order to tackle the problems of deafness and hidden node. The proposed protocol will maximize the spatial reuse and thus improve overall throughput even under node mobility and infrastructureless deployment. Example of the deafness problem. In order to achieve very high throughput communication, the following core functions need to be developed for contention based directional MAC: (1) Minimizing Circular RTS/CTS Overhead: CRTS/CCTS mechanism has a significant number of transmissions for RTS/CTS. In this work, we will minimize the unnecessary overhead. (2) Efficient DNAV(Directional NAV) Computation: We will synchronize the DNAV time among neighboring nodes to avoid deafness problem. (3) RTS/CTS Retransmission Scheme to resolve Deafness Problem: Nodes suffering from deafness will keep sending RTS to designated receiver resulting in unnecessary power consumption. We will rectify this problem using DNAV value for each beam. (4) Intelligent Communication Range Control for Spatial Reuse: Using distance computation from sender to receiver, we will minimize hidden node and deafness problems. (5) Reliable Multicasting: By using reliable and energy-efficient multicasting algorithm, we will minimize the number of ACKs and ACK transmission time. (6) Directional MAC Simulator based on NS-2: we will evaluate the performance of the proposed directional MAC using NS-2 simulator and optimize any performance parameters.

Military network sensor nodes will be extremely small, lightweight and cheap. These are combined with the need for long battery lifetime. These assumptions have led to the following requirements: (a) Tailored routing and transport protocols are needed (b) Short distances between nodes (often just a few metres) are taken for granted (c) Special-purpose operating systems are required. In practice these assumptions are more challenging than required in the near-term for current military needs while other aspects such as tamper-resistance are not addressed.

Military applications are a primary use of wireless networking and are best served by informed research that avoids making assumptions that are based on presumed military requirements. Many research papers propose algorithms and communication approach for network sizes of thousands of nodes and above. In practice these assumptions are more challenging than required in the near-term for current military needs while other aspects such as tamper-resistance are not addressed.

WiMAX mobile devices are known to have severe communication qualities due to signal degradation in cell boundaries and shaded areas. To solve this problem, various researches attempt to increase signal sensitivity in those areas [1][2]. For instance, vehicles can be equipped with WiMAX antenna on the roof or glass of the vehicle so that the mobile devices can increase receiver signal sensitivity. Through this approach, a large variety of applications can be created by passing the WiMAX traffic to mobile devices in the vehicle. The vehicle might use a gateway that transparently distributes the WiMAX data to mobile users to augment the WiMAX data service. One of the potential technologies achieving this goal would be via wireless local area network (WLAN) such as IEEE 802.11. However, if a significant number of APs are densely located, the throughput of the mobile devices will be tremendously degraded due to interference among the WiFi networks. Basic Vehicle Model In this research, we assume that vehicles are embedded with WiMAX antenna which distributes WiMAX traffic to WiFi in-vehicle wireless devices forming a basic service set (BSS). We research a mobility-aware interference avoidance scheme among those BSSs which works well even under the situation that BSSs are densely located. Therefore, to cope with dynamicity of the topology, we exploit mobility vector and location information of neighboring APs from a global positioning system (GPS).