Air Interface and Physical Layer techniques for 60 GHz WPANs

Abstract

Thanks to the unprecedented availability of huge bandwidth, the capacity offered by wireless systems in the 60 GHz band can exceed the mythical barrier of 1 Gbps wireless, enabling the deployment of new applications. However, the performance can be limited by the non-ideality of the analog Front-Ends, multipath fading and the difficulty to achieve a reasonable link budget at high data rates.The goal of this paper is to introduce high rate communications in the 60 GHz band and the associated challenges. We will first introduce WPANs in the 60 GHz band, describing the possible applications, the propagation channel and the standardization context.. Furthermore, based on the characteristics of the propagation channel, we will show that beamforming is desirable to boost the link budget, reduce interference and, in some cases, reduce multipath. Next, we will introduce candidate PHY layer solutions that at the same time meet the throughput requirements and relax the analog frontend design. Our solutions rely on the combination of block transmission combined with (nearly) constant envelope modulation: this provides low peak-to-average power ratios, easy equalization, good spectral properties and modest front-end requirements in terms of phase noise and ADC resolution. The receiver signal processing associated with the modulation techniques will be described and link level simulation results will be provided, highlighting the "front-end friendliness" of the modulation technique.

An Overview of Signal Processing Techniques for Millimeter Wave MIMO Systems

“…The exact power consumption depends on the specifications and technology used to implement a given device. Table I [7], [109], [110], IQ imbalance [111], [112], and nonlinear effects [109], [110], [113]. Modeling these impairments and developing digital compensation algorithms for mmWave is an active area of research [114]- [116].…”

“…There are other implications of different hardware, beyond what is considered in this section, where signal processing can play a role. Examples include phase noise [7], [109], [110], IQ imbalance [111], [112], and nonlinear effects [109], [110], [113]. Modeling these impairments and developing digital compensation algorithms for mmWave is an active area of research [114]- [116].…”

Impact of RF Impairments on the Performance of Multi-carrier and Single-carrier based 60 GHz Transceivers

“…This gives rise to a particular power spectral density (PSD) (instead of a Dirac pulse at the carrier frequency). The PN PSD is usually characterized by 3 parameters [9] i.e. the total double sided integrated PSD K in dBc, the PN spectrum bandwidth f o in Hz and the noise floor L in dBc/Hz.…”

Polarization Effects for Indoor Wireless Communications at 60 GHz

“…It is well known that multipath effects cause intersymbol interference (ISI) for high-speed signaling and ultimately limit the achievable data rate at any frequency band. The spatial and temporal properties of the 60 GHz channel are quite different than those of the lower frequency bands [1], [2]; this leads to the need of novel approaches to mitigate multipath effects in the 60 GHz band. Several approaches have been proposed to improve the performance of the 60 GHz wireless systems through phase noise suppression and different modulation techniques [2]- [4].…”

“…The spatial and temporal properties of the 60 GHz channel are quite different than those of the lower frequency bands [1], [2]; this leads to the need of novel approaches to mitigate multipath effects in the 60 GHz band. Several approaches have been proposed to improve the performance of the 60 GHz wireless systems through phase noise suppression and different modulation techniques [2]- [4]. Use of directional antennas is also an effective method to mitigate multipath effects for the 60 GHz band [5]- [7].…”