On the Performance of MIMO technology for wireless networks

In the domain of wireless networks, IEEE 802.11 was the first wireless networking standard. This legacy standard has many amendments to overcome its limitations such as the low data rate and frequency. The 802.11a, 802.11b, and 802.11g amendments have a maximum data rate of 54Mbps, 11Mbps, and 54Mbps respectively. The latest amendment is 802.11n which incorporates several significant enhancements and gives higher data rate, at least 100Mpbs, longer range and more reliable coverage than the previous amendments. The 802.11n standard based devices can deliver five times or more throughput and more robust connections at up to twice the range of the legacy 802.11 standard .Therefore, this standard is best suited for our homes and business, because it doesn‟t limit our daily activities when used with several devices and in large areas. This standard (802.11n) can be achieved through adding a technology known as multiple input, multiple output (MIMO), that refers to a link for which the transmitting end as well as the receiving end is equipped with multiple antenna elements which causes an improvement in the data rate of the communication. Our project will implement this technology through simulation. Many MAC protocols for implementing directional antennas have been studied. We have searched for existing protocols and understood how they are implemented. One of the protocols doesn‟t know the position of other nodes during the communication. The other protocol depends on the Global Positioning System (GPS) to know the position of other nodes. In our project, we chose to implement the first one using NS2. This protocol should improve the average throughput in the network up to 2 to 3 times by using four directional antennas for each node over that obtained by using the 802.11 standard. In our project we'll use the network simulation tool (NS2) to support us in the 802.11n standard implementation. NS2 simulator is equipped with the legacy system, 802.11, which lacks a lot of features needed by researchers to support their research. Therefore, MIMO project will modify the physical to network layers implementation of the NS2 simulation tool according to 802.11n. MIMO technology will be implemented as a module using C++ language to add new network elements and protocols, and utilizing TCL language as an interface to use existing network elements. After implementation of 802.11n, researchers can easily create different network scenarios based on the 802.11n protocol, and the result of those scenarios will be visualized by a network animator called “NAM”. Also, a trace files will be produced and analyzed using AWK language to extract results and determine the value of a specific feature, such as throughput, packet loss, and some other measurements. Making a comparison between the 802.11 and 802.11n standards will facilitate the testing phase and exploring the improvement found in the 802.11n standard. After finishing the implementation, the code will be posted on the simulator development site under KSU name which will be helpful to many other researchers in their MIMO based research