This chapter has focused on the analysis of doubly massive MIMO mm-wave systems, and it has presented some relevant use cases, focusing on EE issues. In particular, a detailed description of doubly massive MIMO system has been given highlighting the differences with respect to massive MIMO at microwave. Some examples of use-cases of doubly massive MIMO systems have been detailed. Asymptotic formulas for the large number of antennas regime and low -complexity EE-maximizing power allocation strategies have been derived. In particular, two different techniques are described, the first one used the asymptotic expressions in the interference -free case, the second one used the expressions with interference. In both cases, the EE -maximizing power allocation is obtained by means of fractional programing techniques. The obtained results have revealed that, using some of the most recent available data on the energy consumption of transceiver components, FD architectures, especially in the multiple streams transmission, are superior not only in terms of achievable rate but also in terms of EE. In particular, among FD implementations, the PZF architecture has been shown to provide the best performance, while the AB structure can be considered for its extremely low complexity. Of course the provided results and the relative ranking among the considered structures in terms of EE are likely to change in the future as technology progresses and devices with reduced power consumption appear on the scene, even though it may be expected that in the long run FD architectures will be fully competitive, in terms of hardware complexity and energy consumption [17,20,25], with hybrid alternatives.

Chapter Contents:

• 10.1 Introduction
• 10.1.1 State of the art
• 10.1.2 Chapter organization
• 10.1.3 Notation
• 10.2 Doubly massive MIMO systems
• 10.2.1 Differences with massive MIMO at microwave frequencies
• 10.2.2 Use cases
• 10.3 System model
• 10.3.1 The clustered channel model
• 10.3.2 Transmitter and receiver processing
• 10.3.3 Performance measures
• 10.4 Beamforming structures
• 10.4.1 Channel-matched, fully digital (CM-FD) beamforming
• 10.4.2 Partial zero-forcing, fully digital (PZF-FD) beamforming
• 10.4.3 Channel-matched, hybrid (CM-HY) beamforming
• 10.4.4 Partial zero-forcing, hybrid (PZF-HY) beamforming
• 10.4.5 Fully analog beam-steering beamforming (AB)
• 10.5 Asymptotic SE analysis
• 10.5.1 CM-FD beamforming
• 10.5.2 PZF-FD beamforming
• 10.5.3 Analog beamforming
• 10.6 EE maximizing power allocation
• 10.6.1 Interference-free case
• 10.6.2 Interference-limited case
• 10.7 Numerical results
• 10.8 Conclusions
• Acknowledgments
• References

Inspec keywords: telecommunication power management; MIMO communication; mathematical programming; millimetre wave communication

Other keywords: doubly massive MIMO mm-wave systems; doubly massive MIMO millimeter wave wireless systems; fractiona programming techniques; low-complexity EE-maximizing power allocation strategies

Subjects: Telecommunication systems (energy utilisation); Radio links and equipment; Optimisation techniques