The goal of a wireless communication system is to serve as many users with the highest possible data rate given constraints such as radiation power limit and operating budget. To improve the data rate, the key is to improve the signal to noise ratio (SNR). To serve more users, the key is to reuse the resources. Over the last several decades, numerous algorithms have been adopted to improve the SNR and reuse the resources in time, frequency, and coding spaces. This MATLAB example shows how the adoption of antenna arrays can help improve the SNR and capacity of a wireless link.