Recent Developments in Integrated Interferer-Tolerant Receivers for Reconfigurable Radios

Abstract

Fragmented spectrum allocations at RF and mm-Wave, increased use of carrier aggregation/MIMO and dense spectrum-reuse in wireless links has led to interest in the design of integrated wideband, high-linearity MIMO RX that provide low noise, blocker tolerance and reconfigurability across signal domains. In this paper, receive architectures for wide operating range and blocker tolerance are presented with a focus on recent developments in reconfigurable N-path receivers. Generalized sequence-mixing architectures that support reconfigurable frequency/spatial/code-domain rejection and filtering are described along with directions of research extending operation to wider bandwidths and higher frequencies.INDEX TERMS N-path filters, reconfigurable receivers, current-mode, passive mixers, sequence mixers, spatio spectral filtering, walsh function sequence based notch filters, blocker tolerant receivers, blocker tolerant MIMO, interference tolerant receivers.This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination.

A 0.4–1.8-GHz Quarter-Rate Subsampling Mixer-First Direct Down-Conversion RF Front-End

“…In addition, the fundamental and fifth harmonic of f s down-converting the f RF of 1460 MHz to 940 MHz and 980 MHz, respectively are attenuated by 36 dB, and 43 dB with respect to third harmonic down-conversion. In addition to the f RF at 3f s , the mixer also translates the interferers present at the f s and 5f s to the baseband, with conversion gains as explained in Section II-E, quantified by (1,5) V I/Q,3 using the Eq. (5b), and (5c).…”

“…Switch-capacitor receiver RF front-ends are of paramount importance with the ever-increasing demand for a programable RF front-end that supports wide-band operation with low power consumption [1]. In addition, CMOS technology scaling has benefitted the MOS switching properties to realize reconfigurable mixers and filters with low-power consumption.…”