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Wi-Fi On Steroids: 802.11ac and 802.11adLochan Verma, Member, IEEE, Mohammad Fakharzadeh, Senior Member, IEEE, and Sunghyun Choi, Senior

Member, IEEE

Abstract—The advent of bandwidth hungry wireless applica-tions such as large file transfers, high definition video streaming,wireless display, and cellular data offload highlight the impendingneed for larger bandwidth and super speed Wi-Fi links exceeding1 Gbps. This article introduces two emerging standards likelyto shake the wireless world, namely IEEE 802.11ac and IEEE802.11ad, and identifies the challenges in the path of multi-gigabitWi-Fi. We study the suitability of these standards for the newusage models enlisted in this article.

Index Terms—802.11ac, 802.11ad, LTE, multi-gigabit Wi-Fi,backhaul network, wireless display, directional antennas.

I. INTRODUCTION

Wireless networking is a fundamental technology as impor-tant as computing itself. Wi-Fi has pushed the performanceand user experience of wireless to guarantee that it is keepingpace with the ever increasing demand of higher speeds andnew usage models.

With the advent of bandwidth hungry applications, suchas large file transfers (e.g., blue-ray HD movie, raw uncom-pressed images, etc.), HD (High Definition) video streaming,wireless display, and cellular data offload, more bandwidth issorely needed [1]. Wi-Fi is proliferating in the CE (ConsumerElectronics) domain providing a playground for faster mediatransfer communication applications [2]–[4]. Market statisticsproject number of Wi-Fi enabled devices shipped in year 2012to surpass 1.5 billion [5].

Extensive effort and work are in progress in IEEE on twoemerging standards likely to shake up the wireless world:IEEE 802.11ac [6] and IEEE 802.11ad [7]. These standardstarget data rates faster than the gigabit Ethernet. The historyof initiation and development of these standards up to the year2011 is presented in [8].

This article addresses the following critical points.i The need for multi-gigabit Wi-Fi.ii Key PHY (PHYsical) layer features of 802.11ac and

802.11ad that enable multi-gigabit Wi-Fi.iii Challenges for achieving multi-gigabit Wi-Fi.iv Suitable use cases for 802.11ac and 802.11ad.The rest of the article is organized as follows. Section II

justifies the need of multi-gigabit Wi-Fi. Section III presentsemerging multi-gigabit Wi-Fi standards, namely, 802.11ac and802.11ad. Section IV introduces multi-gigabit modulation andcoding schemes, while Section V discusses challenges on theroad to multi-gigabit Wi-Fi. Section VI elaborates adaptability

Manuscript received January 18, 2013; revised April 25, 2013.Lochan Verma and Mohammad Fakharzadeh are with Peraso Technolo-

gies, Inc., Toronto, Canada. (E-mail: {lochan, mohammad}@perasotech.com).Sunghyun Choi is with the School of Electrical Engineer-

ing and INMC, Seoul National University, Seoul, Korea. (E-mail: schoi@snu.ac.kr).

of 802.11ac and 802.11ad for multi-gigabit Wi-Fi use cases.The paper concludes with Section VII.

II. NEED FOR MULTI-GIGABIT WI-FI

Wi-Fi speed has proliferated keeping pace with the usagemodel requirements. As of today, commercially available802.11n-based Wi-Fi products support PHY data rates up to540 Mbps. Wi-Fi use cases have evolved to beyond wirelessLAN (Local Area Networking) for access to the Internet. Thefollowing use cases justify the need for multi-gigabit Wi-Fi.

• Sync Data/File Transfer: Multi-gigabit Wi-Fitremendously reduces the time for data synchronizationbetween two devices. For example, a 1 GB file transferis at least 10 times faster (1 Gbps vs. 100 Mbps). Inhome, enterprize, and public kiosk environments, timefor completion of the activity is critical for a good userexperience.

• Wireless LAN and Backbone Networks:Multi-gigabit Wi-Fi enables faster access to the Internetby improving the PHY data rate between the deviceand the AP (Access Point) and between AP-to-AP inwireless backbone networks.

• Small-Cell Backhaul Network:Mobilebroadband data is growing at exponential rates. LTE(Long Term Evolution) and 5G increase the capacity ofthe network leveraging small cells but it has a majorimpact on the mobile backhaul network design. Backhaulis the transmission link between the small cell and themobile network controller. Small cell controllers will bedeployed in the streets (lamp-posts, street lights, etc.)and their deployment cost must be minimized. Fiber isnot a scalable or cost-efficient way to reach all smallcell sites, so a wireless solution will play a dominantrole. The 60 GHz technology (802.11ad) is an excellentsolution for small cell backhaul since it offers morethan one Gbps link with a low cost, particularly nolicence fee. Thus, mobile broadband technologies andmulti-gigabit Wi-Fi complement each other.

• Multi-media Streaming over IP:Uncompressed video at 1920 × 1080p, 24 bits/pixel,and 60 frames/second generates 3 Gbps of data andrequires at least 3 Gbps PHY data rate for wirelessstreaming. Conventional Wi-Fi can only streamcompressed multi-media contents. Multi-gigabit Wi-Fienables uncompressed multi-media content streaming,achieving the high quality and low end-to-end latencyrequirements critical for smooth user experience inwireless display use cases. Wi-Fi is more suitablecompared to wireless USB [9], WHDI (Wireless High

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IEEE Channel

Number

36

40

44

48

52

56

60

64

10

0

10

4

10

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11

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11

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12

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16

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5170

MHz

5250

MHz

5490

MHz

5250

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5330

MHz

5730

MHz

5735

MHz

5815

MHz

5815

MHz

5835

MHz

UNII-1 UNII-2 UNII-2e UNII-3 ISM

20 MHz

40 MHz

80 MHz

160 MHz

Weather Radar

DFS

Fig. 1. The 5 GHz spectrum available for Wi-Fi usage with DFS and TDWRrestrictions.

Definition Interface) [10], and WiHD (Wireless HighDefinition) [11] for wireless display, since the former hasa larger deployment and user awareness, besides supportfor IP-networking, ease of connection, and standardizedsecurity mechanism [3].

• Cellular Data Offloading: The spectrum avail-able for mobile data applications over cellular networksis limited and even the advent of LTE radio accessis reaching the limits of Shannon’s law. Cellular dataoffloading is one solution to increase the overall cellularnetwork capacity by offloading mobile data to Wi-Fi inhigh density places like shopping malls, universities, en-terprizes, etc. Multi-gigabit Wi-Fi in this setting providesfaster data transfer improving the overall Wi-Fi networkperformance.

III. MULTI-GIGABIT WI-FI STANDARDS

This section discusses key features in 802.11ac and802.11ad enabling multi-gigabit Wi-Fi.

A. IEEE 802.11ac

1) Carrier frequency: IEEE 802.11ac is an amendmentto the IEEE 802.11 [12] for VHT (Very High Throughput)operation in frequency bands below 6 GHz, excluding 2.4GHz, i.e., unlicensed bands at 5 GHz band. Plurality of 802.11a/b/g/n devices are currently operating at 2.4 GHz crowdingthe channels and causing bandwidth crunch and higher signalinterference. The 5 GHz band is comparatively cleaner withlower signal interference. The number of non-overlappingchannels (of 20 MHz each) available at 5 GHz band is larger(24 in the US, up to 24 worldwide) as compared to a few non-overlapping channels at 2.4 GHz (3 in the US), thus enablingchannel bonding of 2 or more channels.

2) Channel bandwidth: As shown in Fig. 1, 5 GHz spec-trum is composed of a number of sub-bands including U-NII(Unlicensed National Information Infrastructure)-1, 2, 2e, and3 bands. The support of DFS (Dynamic Frequency Selection),originally defined in IEEE 802.11h, is mandatory to use UNII-2 and 2e. DFS is the mechanism to ensure that channelscontaining radars are avoided by an AP and the energy isspread across the wireless channel to reduce interference tosatellites.

IEEE 802.11ac supports 40 MHz, 80 MHz, and 160 MHzchannel bandwidth compared to only 20 MHz and 40 MHzsupported by 802.11n. The 160 MHz channel bandwidth is

composed of two 80 MHz channels that may or may not becontiguous. The 80 MHz and 40 MHz channels are composedof two contiguous 40 MHz and 20 MHz channels, respectively.The support of 40 MHz and 80 MHz channel bandwidth ismandatory while support of 160 MHz and 80+80 MHz isoptional.

These wide channel bandwidths and minimized co-channelinterference are challenging to achieve in a dense WLAN en-vironment (for example, enterprize deployment) with pluralityof APs deployed on non-overlapping channels. The 802.11acprovides more spectrum and channel bandwidth by relyingon DFS channels, which many Wi-Fi devices do not supporttoday.

As seen in Fig. 1, 80 MHz channel bandwidth allows 5non-overlapping channels in the U.S. (channels 120-128 areprohibited due to TDWR (Terminal Doppler Weather Radar))and 5 in the UK/EU (channels 149 and higher require lightlicensing for outdoor use only) when DFS is used, but only 2channels in the U.S. and 1 in the UK/EU without DFS. DFSis mandatory for 160 MHz channel bandwidth with 1 non-overlapping contiguous 160 MHz channel in the U.S. and 2in the UK/EU.

3) MIMO: Higher data rate can be achieved with multipleantenna system known as MIMO (Multiple Input MultipleOutput) system. Data for transmission is divided into indepen-dent data streams to be transmitted through multiple antennas.This is known as spatial multiplexing. Typically, a MIMOsystem has m transmit and n receive antennas. The numberof streams M is always less than or equal to the minimumnumber of antennas available in an m×n MIMO system. Thechannel capacity C increases linearly with M,

C = M ×B × log2(1 + SNR),

where B is the channel bandwidth and SNR is the signal-to-noise ratio. The 802.11ac supports up to 8 spatial streamscompared to the maximum 4 in 802.11n.

IEEE 802.11ac supports MU-MIMO (Multi User-MIMO) aswell as SU-MIMO (Single User-MIMO). SU-MIMO as shownin Fig. 2(a) is a method by which an AP can transmit multipleindependent streams at the same time to a single device. MU-MIMO as depicted in Fig. 2(b) is a technique by which theAP can transmit multiple independent streams at the same timeto multiple devices. In 802.11ac, MU-MIMO system supports4 users with up to 4 spatial streams per user with the totalnumber of spatial streams not exceeding 8.

Typically, many of today’s CE devices have one transmitand one receive antenna while the APs have m transmit andn receive antennas. The MU-MIMO system is well suited fordownlink from AP in this situation as the network perfor-mance is improved keeping the complexity of the device sideminimum by using only one receive antenna.

4) Modulation and coding scheme: According to 802.11acthe PHY data sub-carriers are modulated using BPSK (BinaryPhase Shift Keying), QPSK (Quadrature Phase Shift Keying),16-QAM (Quadrature Amplitude Modulation), 64-QAM, and256-QAM. Note that 256-QAM is not supported by 802.11n.FEC (Forward Error Correction) coding is used with coding

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Fig. 2. (a) SU-MIMO concept and (b) Downlink MU-MIMO concept.

Fig. 3. Worldwide frequency allocation for unlicensed operation at 60 GHzband.

rates of 1/2, 2/3, 3/4, and 5/6. Use of BCC (Binary Convolu-tional Coding) is mandatory, but LDPC (Low-Density Parity-Check Coding) is optional.

5) Backward compatibility: IEEE 802.11ac is backwardcompatible with 802.11n at 5 GHz ensuring the interoperabil-ity of 802.11ac and the already deployed 802.11n devices.

B. IEEE 802.11ad

1) Carrier frequency: 802.11ad is an amendment to 802.11for enhancements for multi-gigabit throughput in 60 GHzband. Fig. 3 depicts the spectrum allocation for unlicensedoperation at 60 GHz. In this band, typically 7 GHz of spectrumis available for unlicensed usage compared to 83.5 MHz in 2.4GHz band. This standard defines 4 channels, each with 2.16GHz bandwidth, for operation at 60 GHz band. These channelsare 54 times wider than the 40 MHz bonded channels availablein 802.11n.

2) Modulation and coding scheme: 802.11ad defines bothSC (Single Carrier) modulation and OFDM (Orthogonal Fre-quency Division Multiplexing) modulation. OFDM enableslonger distance communication and greater delay spreads.This provides flexibility in handling obstacles and reflectedsignals. OFDM allows SQPSK, QPSK, 16-QAM, and 64-QAM modulation with the maximum achievable PHY datarate of 6.756 Gbps. SC PHY is low on power consumption andfocusses on small form factor devices like handsets. SC usesπ/2-BPSK, π/2-QPSK, and π/2-16-QAM modulation with themaximum achievable PHY data rate of 4.620 Gbps. In thisstandard, the data is encoded by a LDPC encoder with 1/2,5/8, 3/4, and 13/16 code rates.

3) Beamforming: Signal attenuation is high at 60 GHz bandand hence link budgeting is challenging. To improve the signalstrength at the receiver, high gain antennas are deployed. Thesehigh gain antennas, mostly phased-array antennas, utilizebeamforming to create beams in a particular direction allowingthe transmitted power to be focused.

4) Backward compatibility: The backward compatibilityfactor is irrelevant as IEEE 802.11ad is the first standard forWi-Fi operation at 60 GHz.

IV. MULTI-GIGABIT MODULATION AND CODINGSCHEMES

Multi-gigabit PHY data rates in 802.11ad are achievedby using a large chunk of spectrum (≈2 GHz) with simplemodulation schemes (BPSK, QPSK), while in 802.11ac it isbased on sending more bits per symbol (256-QAM) and useof simultaneous data streams (up to 8), because bandwidth islimited to a maximum of 160 MHz (with channel bonding).

Table I illustrates MCSs (Modulation and Coding Schemes)used in 802.11n, 802.11ac, and 802.11ad to achieve multi-megabit and multi-gigabit PHY data rates. Note that both802.11n and 802.11ac support long guard interval of 800ns and optionally short guard interval of 400 ns betweentransmission of two symbols. The guard interval is 48.4 ns in802.11ad. Table I assumes the long guard interval for 802.11nand 802.11ac. With short guard interval, the data rates increaseaccordingly, e.g., 802.11n’s maximum data rate increases from540 Mbps to 600 Mbps, and 802.11ac’s maximum data rateincreases from 6.240 Gbps to 6.933 Gbps.

The 802.11n PHY data rates range from 6.5 Mbps to 600Mbps, achieved through various combinations of modulationscheme, code rate, channel bandwidth, guard interval, andnumber of spatial streams. 802.11ac PHY data rates rangefrom 6.5 Mbps to 6.933 Gbps. PHY data rates achieved by802.11ac with 256-QAM modulation scheme and by 802.11nwith 64-QAM modulation scheme, 800 ns guard interval, 40MHz channel bandwidth, and 4 spatial streams is 720 Mbpsand 540 Mbps, respectively, i.e., a 33% increase in the PHYdata rate, thanks to 256-QAM modulation scheme.

802.11ad PHY data rates range from 385 Mbps to 6.7Gbps, achieved through combinations of modulation schemeand code rate. For BPSK modulation scheme, PHY data rateachieved by 802.11ad using 2.16 GHz channel bandwidth and802.11n employing 20 MHz channel bandwidth is 385 Mbpsand 6.5 Mbps, respectively, i.e., a 58 times increase in thePHY data rate, leveraging larger channel bandwidth.

V. CHALLENGES FOR MULTI-GIGABIT WI-FI STANDARDS

Table II shows the receiver sensitivity and required trans-mitter EVM (Error Vector Magnitude) values for some keyMCSs of 802.11n, 802.11ac, and 802.11ad. A higher receivesensitivity means that a higher signal strength (or SNR) isrequired for detection. A lower EVM means that system errorssuch as local oscillator phase noise, transmitter nonlinearities,IQ imbalance, etc. must be controlled more precisely.

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TABLE IMODULATION AND CODING SCHEMES FOR 802.11N, 802.11AC, AND 802.11AD

Modulation Code Rate PHY Data Rate (Mbps) SpatialStreams

Standard

20 MHzchannel

40 MHzchannel

80 MHzchannel

160 MHzchannel

2.16 GHzchannel

BPSK 1/2 6.5 13.5 - - - 1 802.11n2

QPSK 3/4 19.5 40.5 - - - 1 802.11n16-QAM 3/4 26 81 - - - 1 802.11n64-QAM 5/6 65 135 - - - 1 802.11n64-QAM 5/6 260 540 - - - 4 802.11n

BPSK 1/2 6.5 13.5 29.3 58.5 - 1 802.11ac2

QPSK 3/4 19.5 40.5 87.8 175.5 - 1 802.11ac16-QAM 3/4 39 81 175.5 351 - 1 802.11ac64-QAM 5/6 65 135 292.5 585 - 1 802.11ac256-QAM 5/61 78 180 390 780 - 1 802.11ac256-QAM 5/61 312 720 1560 3120 - 4 802.11ac256-QAM 5/61 624 1440 3120 6240 - 8 802.11acπ/2-BPSK 1/2 - - - - 385 1 802.11adπ/2-BPSK 3/4 - - - - 1155 1 802.11adπ/2-QPSK 3/4 - - - - 2310 1 802.11ad

π/2 16-QAM 3/4 - - - - 4620 1 802.11ad64-QAM 13/16 - - - - 6756.75 1 802.11ad

1 Code rate of 3/4 for 20 MHz channel width.2 Guard interval = 800ns.

TABLE IITRANSMITTER EVM AND RECEIVER SENSITIVITY FOR A FEW MODULATION AND CODE RATES USED IN 802.11N, 802.11AC, AND 802.11AD

Modulation Code Rate Receive Sensitivity (dBm) EVM (dB)20 MHzchannel

40 MHzchannel

80 MHzchannel

160 MHzchannel

2.16 GHzchannel

BPSK 1/2 -82 -79 -76 -73 - -5QPSK 3/4 -77 -74 -71 -68 - -13

16-QAM 3/4 -70 -67 -64 -61 - -1964-QAM 5/6 -64 -61 -60 -57 - -27

256-QAM 5/6 -57 -54 -51 -48 - -32π/2-BPSK 1/2 - - - - -78 -6π/2-BPSK 3/4 - - - - -64 -10π/2-QPSK 3/4 - - - - -59 -13

π/2 16-QAM 3/4 - - - - -53 -2164-QAM 13/16 - - - - -47 -26

A. Hardware Complexity and Power Consumption

802.11ad systems require a simpler hardware comparedto 802.11ac, due to simpler modulation schemes and useof only one stream of data (SISO vs. MIMO). To havemultiple independent data streams in 802.11ac, multiple RFand baseband chains are required. In practice, for better radiolink performance, the number of RX and TX chains may belarger than the number of desired streams, NS (i.e., numberof independent and separately encoded transmit signals orstreams). This implies more than NS times increase in powerand RF chip/device area.

Even if intelligent power management is applied to TX,MIMO RX system may consume at least NS times morepower compared to a single chain RX. Furthermore, theprocessing power required to form MIMO streams must beadded to the total power budget.

B. Device Form Factor

In a multiple antenna system the adjacent antennas must beseparated by a minimum distance, around half wavelength (27mm for 802.11ac), to reduce the coupling between antennasas well as correlation between streams. For applications wheresize matters, this requirement limits the number of antennas,

and consequently, the number of streams and maximum bit-rate.

At 60 GHz the carrier wavelength is only 5 mm, so relativelyhigh gain antennas can be implemented in a small package.For example, a 13 dB patch array antenna printed on Duroidsubstrate (ϵr = 2.2) occupies an area of 5 mm × 6 mm [13].So, instead of using a dipole antenna with 2 dBi gain on eachside as in 802.11ac, a compact higher gain antenna can beused at each end to compensate for the extra path loss.

C. Semiconductor CostCMOS technology is used for fabrication of Wi-Fi

transceivers. 2.4/5 GHz band Wi-Fi transceivers can be syn-thesized with more conventional CMOS technologies, whichare cheaper whereas 60 GHz Wi-Fi transceivers can only besynthesized with the state-of-the-art CMOS technology (65nm, 40 nm, etc.) As of today, 40 nm CMOS technology isexpensive, thus making 802.11ad transceivers costly comparedto 802.11ac transceivers.

VI. 802.11AC AND 802.11AD SUITABILITY FORMULTI-GIGABIT USE CASES

Considering the challenges discussed in Section V an im-portant question is raised: are 802.11ac and 802.11ad suitable

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for the same type of applications, or there are preferred classesof applications for each one?

To answer this question, first we need to get a better ideaof wave propagation at 5 GHz and 60 GHz bands. At 60 GHzspectrum, radio signals suffer from higher propagation andatmospheric loss compared to 5 GHz. For the same range,free space loss at 60 GHz is 21 dB more than free space lossat 5 GHz (e.g. for 1 m range free space loss is 68 dB at60 GHz, and 47 dB at 5.5 GHz). Note that general rule ofthumb is every 6 dB increase in propagation loss halves thecoverage distance. Furthermore, obstruction loss is significantat 60 GHz. For example, a human body loss is between 20-40dB [14].

Therefore, 802.11ad is more appropriate for line-of-sightroom-scale, low-cost, short-range very high throughput ap-plications, such as in-room (i) uncompressed and lightlycompressed multi-media wireless display, (ii) sync data/filetransfer, etc. IEEE 802.11ac is proper for longer-range highthroughput applications, such as in-home (i) WLAN, (ii)(lightly) compressed multi-media wireless display, etc. Insummary, IEEE 802.11ad leveraging small device form factorand low power consumption characteristics is apt for portablepower-constraint multi-gigabit wireless devices.

While 802.11ac seems to be more appropriate for longerrange applications, the transmitter power regulatory and powerconsumption requirements limit the applicability to the differ-net use cases. As seen in Tables I and II, 802.11ac requires-48 dBm receive sensitivity with 256-QAM modulation and upto 8 spatial streams to achieve multi-gigabit Wi-Fi. To deploythe highest data rates of 802.11ac AC-powered units are moresuitable. Since the obstruction loss at 5 GHz is lower comparedto 60 GHz, multi-gigabit 802.11ac is more appropriate forhome-scale (both line-of-sight and non-line-of-sight) wirelessapplications where portability is not a bottleneck.

On a different note, at 60 GHz high gain antennas withlow cost and small size can be realized for point to pointapplications such as small-cell backhaul networks. Despitelower propagation loss at 5 GHz band, strict regulatoryrequirements limit the transmit power proportional to thetransmitter antenna gain [15]. Thus range extension requiredfor backhaul networks cannot be achieved at 5 GHz.

VII. CONCLUSIONS

In this article the need of multi-gigabit Wi-Fi links isarticulated. We introduce two emerging standards likely toshake the wireless world: 802.11ac and 802.11ad, highlightthe challenges in the path of multi-gigabit Wi-Fi, and discusssuitability of 802.11ac and 802.11ad for supporting multi-gigabit use cases. Wi-Fi is booming rapidly and is used forwireless connectivity between devices in plethora of scenarios.It remains to be seen how the consumer market responds tomulti-gigabit Wi-Fi link capabilities.

REFERENCES

[1] L. Verma and S. S. Lee, “Proliferation of Wi-Fi: Opportunities in CEEcosystem,” in Proc. PerNets 2011, Las Vegas, USA, Jan. 2011.

[2] ——, “Multi-Band Wi-Fi Systems: a New Direction in Personal andCommunity Connectivity,” in Proc. ICCE 2011, Las Vegas, USA, Jan.2011.

[3] ——, “Wireless Display: An Unmet Need in CE Ecosystem,” in Proc.ICUFN 2011, Dalian, China, Jun. 2011.

[4] ——, “On Method of Transmitting User Interaction Inputs in Wi-FiWireless Display,” in Proc. ICCN 2011, Maui, Hawaii, Jul. 2011.

[5] ABI Research. http://www.abiresearch.com/press/wi-fi-enabled-device-shipments-will-exceed-15-bill.

[6] IEEE 802.11ac. http://www.ieee802.org/11/Reports/tgac update.htm.[7] IEEE 802.11ad. http://www.ieee802.org/11/Reports/tgad update.htm.[8] Eldad Perahia and Michelle X Gong, “Gigabit Wireless LANs: an

Overview of IEEE 802.11ac and 802.11ad,” ACM SIGMOBILE MobileComputing and Communications Review (MC2R), vol. 15, no. 3, pp.23–33, 2011.

[9] USB Implementors Forum. http://www.usb.org/developers/wusb/.[10] Wireless High Definition Interface. http://www.whdi.org/.[11] Wireless High Definition. http://www.wirelesshd.org/.[12] IEEE 802.11-2012, Part 11: Wireless LAN Medium Access Control

(MAC) and Physical Layer (PHY) specifications, IEEE Std., Mar. 2012.[13] B. Biglarbegian, M. Fakharzadeh, D. Busuioc, M. Nezhad-Ahmadi, and

S. Safavi-Naeini, “Optimized Microstrip Antenna Arrays for EmergingMillimeter-wave Wireless Applications,” IEEE Trans. Antennas Propa-gation, vol. 59, no. 5, pp. 1742–1747, 2011.

[14] M. Fakharzadeh, M. Nezhad-Ahmadi, B. Biglarbegian, J. Ahmadi-Shokouh, and S. Safavi-Naeini, “CMOS Phased Array TransceiverTechnology for 60 GHz Wireless Applications,” IEEE Trans. AntennasPropagation, vol. 58, no. 4, pp. 560–573, 2010.

[15] FCC Radio Frequency Regulation. http://www.gpo.gov/fdsys/pkg/CFR-2005-title47-vol1/xml/CFR-2005-title47-vol1-sec15-407.xml.

Lochan Verma is a Sr. Staff Engineer at PerasoTechnologies, Toronto, Canada, developing 60 GHzsystems for consumer electronics and small cellbackhaul. Prior to joining Peraso, he was a ResearchEngineer at Samsung Electronics, Suwon, SouthKorea. He has a decade of industry experience inwireless communications and has served as the ViceChair of WFA Wi-Fi Display technical task group.As a technology visionary, he has authored morethan 20 patents and international publications.

Mohammad Fakharzadeh received the PhD inelectrical engineering from University of Waterloo,Canada in 2008, and the M.Sc. in electrical engineer-ing from Sharif University of Technology in 2002.He is a Senior Staff Engineer at Peraso Technolo-gies, Toronto, Canada, developing millimeter-wavesolutions for portable electronic devices, and smallcell backhaul. Dr. Fakharzadeh has more than 12years of experience in design and implementationof multiple antenna systems, and millimeter-wavetechnology, particularly physical layer design. Dr.

Fakharzadeh is a Senior Member of IEEE, and author of more than 50scientific papers and patents.

Sunghyun Choi is a professor at the Departmentof Electrical and Computer Engineering, Seoul Na-tional University (SNU), Korea. Before joining SNUin 2002, he was with Philips Research USA. Hereceived his B.S. (summa cum laude) and M.S.degrees from KAIST, and received a Ph.D. fromThe University of Michigan. He coauthored over 160papers and holds about 100 patents. He is serving aseditors of IEEE Transactions on Mobile Computingand IEEE Wireless Communications.