Channel Aware MAC Protocol (CA-MAC) Abdulfattah Mohammadtaher Noorwali Communication System and Data Networking University of Western Ontario London, Canada afnoorwali@gmail.com Abstract— Multiple-Input Multiple-Output (MIMO) system provides high spectral efficiency and data rates by establishing simultaneous transmissions through multiple antennas at the transmitter and at the receiver. In this work, spatial multiplexing with beamforming and space-time coding (STC) modulation is proposed to increase the spectral efficiency with special attention to MAC protocol. In this work, intelligent distributed Channel aware MAC protocol (CA-MAC) is proposed. The proposed work will take advantage of MIMO technology to improve the throughput. The proposed algorithm utilizes weighting nulling technique, which is based on tuning in/tuning out. The proposed algorithm will also employ ZigZag-decoding model to recover the data after any collision if occurred. CA-MAC scheme allows transmission of multiple packets through multiple antennas with higher data rate in different conditions of the wireless channel. The simulations would be carried out using NS-2 simulator in this work and results would be examined. MATLAB will also be used to help in analyzing the results. This proposed scheme would be presented for the performance improvements in aggregate network throughput compared with an existing MAC schemes. Keywords-component; Channel Aware; Space Time Coding; ZigZag-decoding; Spatial Myltiplexing, Beamforming I. INTRODUCTION The current Wireless Local Area Networks (WLANs) devices utilize complex mechanisms to allow many users to share networks. Because of that, devices should have an inherent property to access and share the wireless medium. Meanwhile, current technologies require advanced control access mechanisms to the channel for completing successful transmission operation. Recently, to enable successful utilize, experts have achieved important required using multiantennas in both side; consequently, this inspired Wittneben in 1991 to come up with new technique which is called Multiple-input multiple-output (MIMO)[3]. The advantage of MIMO system is to maximize the capacity; however, applying significant modifications measures in MAC protocol should also be ensured. Many researchers are still paying attention on designing MAC schemes for industry purpose. In this work, MIMO systems are exploited as a method of improving WLAN functioning by use of spatial multiplexing with beamforming and STCs modulation, which are scheduled to increase the spectral efficiency with special measures in MAC protocol. The new intelligent distributed Channel aware MAC protocol (CA-MAC) is introduced, and that consequently leaded to use MIMO antenna technology for improving the throughput. This proposed algorithm utilizes weighting nulling technique, which is using for tuning in/ tuning out, and ZigZag-decoding model to recover the data after any collision if it is occurred. The analysis of these results are examined and curried out using NS-2 simulator, which is pointing out the detailed performance, and using MATLAB for doing analytical examine. CA-MAC scheme allows transmitting multiple packets with higher data rate in different condition scenarios of the wireless channel overlapped in time. This proposed scheme is presented the performance improvements in aggregate network throughput compared with an existing MAC scheme. The reminder of this work is organized as follows. Section II provides background on the role of medium access control schemes as well as a detailed background on MIMO technology and Quality of Service in MAC schemes. In Section III Channel- aware MAC protocol (CA-MAC) is proposed with results. Analysis are detailed and compared with a specific MAC scheme is discussed in Sections IV & V. Section VI concludes this paper and offers future research directions and suggestions. II. ENVIRONMENT PREPRARTION A. MAC and MIMO System Adoption The high level of spectral efficiencies attained by a MIMO system due to the fact that, in a rich scattering environment, the signals from each individual transmitter appear to be highly uncorrelated at each of the receiving antennas. For making transmissions using spatial multiplexing, the data should be divided into symbols that are mapped into a sequence. However, when they are passed through the channel, these data are affected by the random noise of the channel. This form of interference might cause confusing inconsistencies in the input data. Spatial multiplexing, on the other hand, will allow a station to produce multiple data streams simultaneously from different antennas each of which would be considered as a separate channel. The beamforming technique is then used to avoid any other interface in the signal transmission. Thus, the entire signal spectrum can be made fully efficient. The availability of this technology will eventually cause all wireless stations to elect to transfer to particular stations. The range of the transmissions will also be improved because the transmitter point will be focused in the target receiver direction. Indeed, the signal to noise ratio (SNR) will increase and it will be the same as the range of