Method for Spectrum Sharing by Cellular and WiFi Networks Based on Cognitive Beamforming

INV-19022

Background

In today’s cellular world mobile data traffic is increasing at an unprecedented rate, which poses a significant burden on the capacity of the underlying wireless network infrastructure - a problem often referred to as spectrum crunch. To address this challenge, researchers have been exploring new spectrum management/sharing approaches to allow next-generation wireless networks (5G and beyond) to achieve more flexibility, higher spectral efficiency, and ultimately higher network capacity.

There are several challenges that need to be addressed to enable efficient and practical spectrum sharing. First, it is difficult to achieve efficient spectrum sharing while guaranteeing fairness among coexisting wireless systems that rely on different and incompatible spectrum access techniques. Second, it is challenging for heterogeneous technologies sharing the same spectrum to achieve harmonious coexistence without implementing specific cross-technology coordination signaling procedures, often requiring substantial modification of the protocol stack. The problem is even exacerbated when multiple service providers are involved, because of the lack of coordination among them.

Technology Overview

Northeastern university inventors are addressing this essential yet challenging problem in 5G wireless networks: of how to enable spectrally-efficient spectrum sharing for heterogeneous wireless networks co-located in the same spectrum bands with different, possibly incompatible, spectrum access technologies without modifying the protocol stacks of existing wireless networks.

To address these issues, the system challenges that need to be addressed to enable a new spectrum sharing paradigm based on beamforming (also referred to as CoBeam) were explored by the group. In CoBeam, a newly-deployed wireless network is allowed to access a spectrum band based on cognitive beamforming without mutual temporal exclusion, i.e., without interrupting the ongoing transmissions of coexisting wireless networks on the same bands; and without cross-technology communication.

The main components of CoBeam, include a programmable physical layer driver, cognitive sensing engine, beamforming engine, and scheduling engine. A practical coexistence scheme between Wi-Fi and cellular networks on unlicensed bands was designed in order to showcase the potential of the CoBeam framework. A prototype of the resulting coexisting Wi-Fi/cellular network was built on off-the-shelf software radios. Experimental performance evaluation results indicate that CoBeam can achieve significant throughput gain, while requiring no signaling exchange between the coexisting wireless networks.

Benefits

Spectrum sharing via cognitive beamforming
Interference with ongoing Wi-Fi transmission
Simultaneous same-space, same-band, same-time cellular transmission with Wi-Fi, minimization
Spectrum sharing via interference nulling is achieved at the price of no cross-technology signaling
Spectrum sharing doesn’t require any alteration of the standard protocol stack of Wi-Fi (IEEE802.11)
The cognitive beamforming-based spectrum access scheme features a programmable protocol stack, that, operates at the lower layers of the protocol stack which can therefore be adopted by multiple cellular technologies to share spectrum with Wi-Fi