Efficient Wireless Signal Optimization Scheme for 5G Mobile Communications

One of the defining characteristics of the next generation of mobile communications will be the use of a multitude of lower-power antennas to maintain ubiquitous high-performance signal coverage. A team of researchers at KAUST recently developed a signal optimization algorithm for future networks that, for the first time, can deliver the full performance promised by 5G communications.

According to the researchers, MIMO systems, involve a very large number of antennas at both the receiver and transmitter in order to achieve superior performance over single-antenna systems or small arrays. Currently, it is difficult to reach the promised theoretical performance of massive MIMO systems because the available algorithms for signal optimization require intensive digital processing, which introduces delays that can obstruct real-time interactions.

Although next-generation networks are capable of high data-transmission speeds, the data itself can be delayed. Minimizing the component of transmission time, called latency in complex networks, has been one of the main obstacles to the development of next-generation communications. The current signal decoding schemes suitable for MIMO are either too computationally intensive or fail to provide performance anywhere near that theoretically possible for 5G.

The research team collaborated with the University’s Extreme Computing Research Center to develop a promising algorithm called spherical decoding that has the potential to provide more efficient signal optimization. The complexity of spherical decoding can be much lower than that of “brute force” decoding methods, but its latency is still too high in huge MIMO networks and there is no systematic way to optimize the search parameters. The researchers demonstrated analytically and via exhaustive simulations that the search spheres can be tuned to achieve the best complexity-performance tradeoff.

The researchers found that the spherical decoding scheme - when combined with parallel computation and optimization for modern graphics processors - can achieve an unprecedented performance gain in large antenna communication systems. For example, in a typical MIMO environment, the spherical decoding algorithm achieves a latency of less than 10 milliseconds, which is required for mobile communications, and a low-bit error rate at a signal power more than 10 times lower than that of other schemes.

The researchers believe that this could help the future deployment of large antenna systems that can offer high-spectral efficiency and low-bit-error rates, while having low-decoding complexity. The problem is of crucial interest in wireless communication and has considerable commercial potential among multimedia wireless service providers.