Energy-Proportional Single-Carrier Frequency Domain Equalization for mmWave Wireless Communication

mmWave wireless communication is proposed for high-throughput and high-density applications. Due to the large channel bandwidth, mmWave systems face a large variation in the observed delay spread. Many proposed single-carrier (SC) mmWave systems rely on cyclic-prefix (CP) frequency domain equalization (FDE) in order to deal with worst case channel conditions. A downside of CP-FDE receivers is their constant energy consumption independent of the actual channel conditions. The alternative overlap-save (OS) FDE receiver can adapt its complexity, but exhibits an inferior equalization performance. By proposing a hybrid FDE approach the receiver can adapt its complexity and therefor its power consumption dynamically to the given channel conditions. Using the structural similarity of overlap-save and cyclic-prefix FDE architectures the proposed hybrid receiver can switch between the two modes of operation with minimum required hardware overhead. It is shown that the proposed hybrid receiver can significantly reduce its complexity in benign channel conditions while still matching the equalization properties of a conventional CP-FDE receivers in very frequency selective environments

Joint power and beamwidth optimization for full duplex millimeter wave indoor wireless systems

In this paper, a joint power and beam-level beamwidth control scheme is proposed for full duplex (FD) millimeter wave (mmWave) indoor wireless systems. Energy efficiency of the proposed scheme is investigated considering various system parameters, such as maximum transmit power level, level of self-interference cancellation and pilot transmission overhead. With this analysis for a realistic indoor wireless communication scenario, the feasibility of FD is studied for mmWave links, considering their specific propagation characteristics, namely, narrow transmission and reception beam-level beamwidths and high absorption losses, as well as massive bandwidth which is much larger than the existing sub 6 GHz bands. We evaluate the performance of the proposed FD mmWave system for three power budget schemes (low, moderate and high) in terms of average total energy efficiency. Our simulation results show that, for currently available state-of-the-art self-interference cancellation levels, FD mmWave with proposed joint power and beam-level beamwidth control outperforms the smart half duplex (HD) mmWave with joint transmission slot and beam-level beamwidth control by a factor of up to four times and improves FD mmWave with only power control by up to 33.92 %. If higher (close to ideal) selfinterference cancellation can be achieved, the net average total energy efficiency improvements over existing abovementioned schemes, are up to 4.8 times and 26.45 %, respectively. It is concluded that with the proposed joint power and beamwidth control, the current FD mmWave technology promises a good potential for indoor wireless networks

Novel Method for Broadband On-Chip Noise Characterization

A novel method for on-chip noise characterization of mm-wave circuits is presented. Different available methods for noise measurements and requirements for on-chip noise mea-surements are studied. The Y-factor method is chosen to be the more suitable method for in-situ applications since it does not require absolute measurements. A state of the art CMOS noise source is implemented in 32nm SOI CMOS technology to enable the in-situ noise measurements of a 20-35 GHz reconfigurable low noise amplifier. Measurement results show that the ENR of the noise source is repeatable enough so that the calibration of the noise source is only required for one integrated circuit. Using different scenarios for the noise figure response of the LNA, the performance of the noise source is evaluated. To the authors’ knowledge, this is the first time that an on-chip CMOS noise source is used for in-situ noise characterization of mm-wave frequency circuits