Towards Spatial Multiplexing in Wireless Networks within Computing Packages

TL;DR

This paper explores the feasibility of using compact antenna arrays in wireless Networks-on-Chip to enable spatial multiplexing, aiming to increase concurrent channels and aggregate bandwidth at millimeter-wave frequencies.

Contribution

It presents a feasibility study demonstrating the creation of multiple independent channels on a chip using antenna arrays at 60 GHz, advancing wireless interconnect technology.

Findings

Two parallel channels achieved with 40 dB SIR at 60 GHz

Channels radiate from opposite chip corners, proving independence

Potential to expand to more channels and higher frequencies

Abstract

Wireless Networks-on-Chip (WNoCs) are regarded as a disruptive alternative to conventional interconnection networks at the chip scale, yet limited by the relatively low aggregate bandwidth of such wireless networks. Hence, any method to increase the amount of concurrent channels in this scenario is of high value. In this direction, and since WNoC implies close integration of multiple antennas on a chip anyway, in this paper we present a feasibility study of compact monopole antenna arrays in a flip-chip environment at millimeter-wave and sub-terahertz frequencies. By means of a full-wave solver, we evaluate the feasibility to create, at will, concentrations of field in different spots of the chip. This way, we set the steps towards spatial multiplexing that enables concurrent multicast communications and also increases the aggregate bandwidth of the wireless network. Our results at 60 GHz show two clearly separable parallel channels that radiate simultaneously from two opposite corners of the chip, achieving a Signal-to-Interference Ratio (SIR) of around 40 dB, which proves that the channels are independent of each other even in such an enclosed environment. Further, we see potential to expand our approach to three or more concurrent channels, and to frequencies beyond 100 GHz.