Submission doc.: IEEE 11-13/1440r0 November 2013 Clayton Shepard, Rice UniversitySlide 1 Argos | Practical Massive-MIMO Date: 2013-11-12 Authors:

Submission

doc.: IEEE 11-13/1440r0November 2013

Clayton Shepard, Rice UniversitySlide 1

Argos | Practical Massive-MIMODate: 2013-11-12

Name Affiliations Address Phone email Clayton Shepard Rice University 6100 Main St.

Houston, TX 77005 713-348-0000 [email protected]

Lin Zhong Rice University 6100 Main St. Houston, TX 77005

713-348-0000 [email protected]

Narendra Anand Rice University 6100 Main St. Houston, TX 77005


Hang Yu Rice University 6100 Main St. Houston, TX 77005


Oscar Bejarano Rice University 6100 Main St. Houston, TX 77005


Edward Knightly Rice University 6100 Main St. Houston, TX 77005


Li Erran Li Alcatel-Lucent 600 Mountain Ave. New Providence, NJ 07974


Authors:

Submission



Abstract

We present a practical architecture for massive-MIMO and show early results from a real-world prototype. We suggest a small modification to 802.11ac to enable implicit channel sounding, which is critical for the practicality of massive-MIMO.

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doc.: IEEE 11-13/1440r0


Massive-MIMO Benefits

• Huge improvements in spectral capacity

• Reduced inter-AP interference

• Reduced STA power

• Increased range

November 2013

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doc.: IEEE 11-13/1440r0


Scalability Challenges

1) Acquire CSIM pilots, then M•K feedback

2) Calculate WeightsO(M•K2), non-parallelizable, centralized data

3) Apply Linear PrecodingO(M•K), then O(M) data transport

November 2013

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doc.: IEEE 11-13/1440r0

Clayton Shepard, Rice University

Argos’ Solutions

Slide 5

November 2013

1) Acquire CSINew reciprocal calibration method

2) Calculate WeightsNovel distributed beamforming method

3) Apply Linear PrecodingCarefully designed scalable architecture

O(M•K) → O(K)

O(M•K2) → O(K)*

O(M•K) → O(K) *

Ref: [1]

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doc.: IEEE 11-13/1440r0

Argos Architecture


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Slide 6

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doc.: IEEE 11-13/1440r0


Argos Implementation

Slide 7

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Slide 8

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Slide 9

WARP Modules

Central Controller

Argos Hub

Clock Distribution

Ethernet Switch

SyncDistribution

Argos Interconnects


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Ref: [3]

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Slide 11

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ArgosHub

Slide 12 Clayton Shepard, Rice University

November 2013

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doc.: IEEE 11-13/1440r0

ArgosMobile


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Slide 13

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doc.: IEEE 11-13/1440r0

Results Without Considering Overhead

CE TransmitComp


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Slide 14

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doc.: IEEE 11-13/1440r0

Capacity vs. AP Antennas with 15 STAs

Linear Gains as # AP Antennas Increases


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Slide 15

Ref: [1]

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doc.: IEEE 11-13/1440r0

Capacity vs. # of STAs, 64 AP antennas

Linear Gains as # of STAs Increases


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Slide 16

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doc.: IEEE 11-13/1440r0

Capacity vs. # of STAs, 16 AP antennas

Scaling # of STAs with 16 AP Antennas


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Slide 17

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doc.: IEEE 11-13/1440r0

Zero-forcing vs. Conjugate

Slide 18

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1 GHz 10 GHz

ConjugateAdaptivePrecodingZero-forcing

Faster ProcessingMore Antennas or Higher Mobility

Ref: [2]Clayton Shepard, Rice University

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doc.: IEEE 11-13/1440r0


Massive-MIMO in 802.11

Slide 19

November 2013

• TDD

• Low Mobility

• High Frequency (5.8 GHz)

• CSMA

• Expensive

• Large Form-Factor

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doc.: IEEE 11-13/1440r0


Current 802.11ac Sounding

Slide 20

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NDPA

ackCSI

ackCSI

DataNDP

ackCSIRx A

Tx

Rx B

Rx C

Transmission Procedure1. Select transmission group (NDPA)2. Send channel sounding training sequence (NDP)3. Receive channel state feedback (CSI) from each receiver serially4. Construct steering weights and transmit data5. Acknowledge transmission

<<

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doc.: IEEE 11-13/1440r0


Modified Implicit Sounding

Slide 21

November 2013

NDPA

ackNDP

ackNDP

Data

ackNDPRx A

Tx

Rx B

Rx C

Transmission Procedure1. Select transmission group (NDPA)2. Group serially transmits implicit sounding training sequence (NDP)3. Construct steering weights and transmit data4. Acknowledge transmission

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doc.: IEEE 11-13/1440r0


802.11n Implicit Sounding

High-overhead

Required inter-STA cooperation for calibration

Slide 22

November 2013

Ref: [4,5,6,7]

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doc.: IEEE 11-13/1440r0


Conclusions

Massive-MIMO can be practical

Massive-MIMO requires implicit sounding to be feasible

Implicit sounding is easily enabled in 802.11

Slide 23

November 2013

http://argos.rice.edu

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References

[1] Clayton Shepard, Hang Yu, Narendra Anand, Erran Li, Thomas Marzetta, Richard Yang, Lin Zhong. "Argos: Practical Many-Antenna Base Stations," in Proc. ACM Int. Conf. Mobile Computing and Networking (MobiCom), August 2012.

[2] Clayton Shepard, Narendra Anand, and Lin Zhong. "Practical Performance of MU-MIMO Precoding in Many-Antenna Base Stations," in Proc. ACM workshop on Cellular networks (CellNet), June 2013.

[3] Clayton Shepard, Hang Yu, and Lin Zhong. "ArgosV2: A Flexible Many-Antenna Research Platform," Extended Abstract for demonstration in Proc. ACM Int. Conf. Mobile Computing and Networking (MobiCom), October 2013.

[4] 04/1404r2, Enhancements for 802.11: Features and Performance, John Ketchum.

[5] 04/1449r1, High-Throughput Enhancements for 802.11: PHY Supplement, John Ketchum.

[6] 05/0414r1, Response to “No” Vote Comments on Calibration, John Ketchum.

[7] IEEE 802.11n-2009

[8] 13/1046r1, Discussion on Massive MIMO for HEW, Zhigang Wen.

Documents

Submission doc.: IEEE 11-13/1440r0 November 2013 Clayton Shepard, Rice UniversitySlide 1 Argos | Practical Massive-MIMO Date: 2013-11-12 Authors: