BigStation: Enabling Scalable Real-time Signal Processing in Large MU-MIMO Systems

Qing Yang, Xiaoxiao Li, Hongyi Yao, Ji Fang, Kun Tan, Wenjun Hu, Jiansong Zhang, and Yongguang Zhang

Abstract

Multi-user multiple-input multiple-output (MU-MIMO) is the latest

communication technology that promises to linearly increase

the wireless capacity by deploying more antennas on access points

(APs). However, the large number of MIMO antennas will generate

a huge amount of digital signal samples in real time. This imposes

a grand challenge on the AP design by multiplying the computation

and the I/O requirements to process the digital samples. This

paper presents BigStation, a scalable architecture that enables realtime

signal processing in large-scale MIMO systems which may

have tens or hundreds of antennas. Our strategy to scale is to extensively

parallelize the MU-MIMO processing on many simple and

low-cost commodity computing devices. Our design can incrementally

support more antennas by proportionally adding more computing

devices. To reduce the overall processing latency, which is

a critical constraint for wireless communication, we parallelize the

MU-MIMO processing with a distributed pipeline based on its computation

and communication patterns. At each stage of the pipeline,

we further use data partitioning and computation partitioning to increase

the processing speed. As a proof of concept, we have built a

BigStation prototype based on commodity PC servers and standard

Ethernet switches. Our prototype employs 15 PC servers and can

support real-time processing of 12 software radio antennas. Our results

show that the BigStation architecture is able to scale to tens to

hundreds of antennas. With 12 antennas, our BigStation prototype

can increase wireless capacity by 6.8 with a low mean processing

delay of 860s. While this latency is not yet low enough for

the 802.11 MAC, it already satisfies the real-time requirements of

many existing wireless standards, e.g., LTE and WCDMA.

Details

Publication typeInproceedings
Published inACM SIGCOMM
PublisherACM
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