PHY-MAC MIMO Precoder Design for Sub-6 GHz Backhaul Small Cell

The demand for wireless services is becoming much more significant than the currently available spectrum could accommodate. Therefore, improvements at the physical layer alone cannot sustain such high data rates. Extreme densification of wireless networks (e.g., small cells) and the use of additional bandwidth are necessary to meet this increasing demand. On the other hand, multiple-input-multiple-output (MIMO) technology was also introduced to overcome the saturated data rate capabilities of conventional single antenna systems given the limited bandwidth and power levels. However, among various performance aspects and design problems regarding MIMO, precoding is one of the most crucial function components to ensure reliable communication. Without precoding, inter-stream interference can be severe even with cross-pol antenna design. However, the precoding could help to reduce the inter-stream interference and increase the signal strength along the desired signal subspace. In this work, a low complexity design a PHY-MAC precoder for sub-6 GHz backhaul small cell is proposed. The simulations were performed using an SUI-3 channel model for fixed wireless applications.