ArticlePDF Available


Multiple GHz of internationally available, unlicensed spectrum surrounding the 60 GHz carrier frequency has the ability to accommodate high-throughput wireless communications. While the size and availability of this free spectrum make it very attractive for wireless applications, 60 GHz implementations must overcome many challenges. For example, the high attenuation and directional nature of the 60 GHz wireless channel as well as limited gain amplifiers and excessive phase noise in 60 GHz transceivers are explicit implementation difficulties. The challenges associated with this channel motivate commercial deployment of short-range wireless local area networks, wireless personal area networks, and vehicular networks. In this paper we detail design tradeoffs for algorithms in the 60 GHz physical layer including modulation, equalization, and space-time processing. The discussion is enhanced by considering the limitations in circuit design, characteristics of the effective wireless channel (including antennas), and performance requirements to support current and next generation 60 GHz wireless communication applications.
60 GHz Wireless
Emerging Requirements
and Design
Robert C. Daniels and Robert W. Heath, Jr.,
The University of Texas at Austin
1. Introduction
he growth of wireless communications is spurred by the consumer
desire for untethered access to information and entertainment. While
contemporary unlicensed systems support light and moderate levels
of wireless data traffic, as seen in Bluetooth and wireless local area
networks (WLANs), current technology is unable to supply data rates com-
parable to wired standards like gigabit Ethernet and high-definition multime-
dia interface (HDMI). Fortunately, as illustrated in Figure 1, an abundance of
widely available spectrum surrounding the 60 GHz (60G) operating frequen-
cy has the ability to support these high-rate, unlicensed wireless communi-
cations. While unlicensed spectrum around 2.5 GHz and 5 GHz is also
available internationally, the amount of available 60G bandwidth is an order
of magnitude above that available at 2.5 GHz and 5 GHz.
Abstract: Multiple GHz of internation-
ally available, unlicensed spectrum
surrounding the 60 GHz carrier fre-
quency has the ability to accommo-
date high-throughput wireless
communications. While the size and
availability of this free spectrum make
it very attractive for wireless applica-
tions, 60 GHz implementations must
overcome many challenges. For
example, the high attenuation and
directional nature of the 60 GHz wire-
less channel as well as limited gain
amplifiers and excessive phase noise
in 60 GHz transceivers are explicit
implementation difficulties. The chal-
lenges associated with this channel
motivate commercial deployment of
short-range wireless local area net-
works, wireless personal area net-
works, and vehicular networks. In this
paper we detail design tradeoffs for
algorithms in the 60 GHz physical
layer including modulation, equaliza-
tion, and space-time processing. The
discussion is enhanced by considering
the limitations in circuit design, char-
acteristics of the effective wireless
channel (including antennas), and
performance requirements to support
current and next generation 60 GHz
wireless communication applications.
Digital Object Identifier 10.1109/MVT.2008.915320
The actual regulations for radiating devices vary per national entity in terms of allowable output
power, legal supported applications, antenna gain limitations, and other related parameters. For a
more specific treatment of 60G regulatory guidelines, see [1].
Unfortunately, 60G systems exhibit several challenges
that have made them difficult to deploy. The 60G wireless
channel shows 20 to 40 dB increased free space path loss
and suffers from 15 up to 30 dB/km atmospheric absorp-
tion depending on the atmospheric conditions. Multipath
effects, except for indoor reflections, are vastly reduced
at 60G making non-line-of-sight (NLOS) communication
very difficult. Furthermore, millimeter-wave transceivers
are presented with new design challenges such as
increased phase noise, limited amplifier gain, and the
need for transmission line modeling of circuit compo-
nents. Consequently, the design of 60G systems is not
There are several surveys of 60G wireless communica-
tion that summarize 60G design tradeoffs. The current liter-
ature, however, lacks a detailed discussion of modulation,
equalization, and algorithm design at the physical layer.
For example [2], [3], [4] provide early surveys of 60G com-
munications, but focus more on channel characterization
or the supported applications. More recently, [1], [5]–[7]
have presented summaries on CMOS implementation [5],
amplifier design [6], and broad surveys of 60G wireless [1],
[7]. While [1] and [7] are similar in flavor to this article, nei-
ther provide a comprehensive overview of physical layer
algorithm design in 60G systems.
This paper provides two main contributions. First, this
paper summarizes the wireless applications that are well
suited for 60G, listing the advantages and drawbacks of a
60G implementation. Second, this article analyzes trade-
offs in modulation, equalization, and general physical
layer algorithm selection. This tradeoff is reinforced with
a preview of the physical layer for the IEEE 802.15.3c stan-
dard in development. To this end, Section II surveys 60G
channel characteristics and Section III summarizes
millimeter-wave circuit design issues. Building on the
background presented in these sections, Section IV will
discuss modulation and signal processing techniques to
compensate for and leverage the characteristics of the
wireless channel and transceiver design. Section V sug-
gests the most suitable applications to be supported at
60G. Next, Section VI summarizes the proposals for the
IEEE 802.15.3c 60G standard. Section VII describes future
technologies that may change the landscape of the 60G
market. Finally, Section VIII provides a brief summary of
the previous sections.
2. 60G Wireless Channel Characterization
Wireless channel characteristics must be well understood
to determine the appropriate system design at 60G.
Large-scale effects suggest range limitations for line-of-
sight (LOS) communication. Material propagation of 60G
radiation characterizes the performance indoors. The
extent of multipath determines the complexity of receiver
structures for equalization as well as the ability to com-
municate in NLOS scenarios. Multipath can be considered
in several contexts. In the context of transmit and receive
antennas, the severity of multipath depends both on
antenna directivity and polarization. How the multipath
changes with time determines the time coherence of the
channel while the spatial richness of the multipath sug-
gests whether spatial processing techniques are worth-
while. In this section, the properties of the 60G channel
and its implications are summarized.
2.1 Large Scale and Outdoor Channel Effects
Path loss is a measure of average radio wave energy
decay as a function of distance, frequency, and other
location specific parameters. Simple calculations using
the Friis free-space path loss formula show a 20–40 dB
power penalty for 60G versus unlicensed communica-
tion at operating frequencies below 6 GHz. Loss due to
atmospheric absorption can account for an additional
7–15.5 dB/km power loss in the received signal at 57–64
GHz carrier frequencies [3]. Although water vapor does
not contribute greatly to signal attenuation at normal
concentrations, rain droplets that form when the
atmosphere becomes saturated can further attenuate
the signal. For example, given a rainfall rate of 50
mm/hour, different models predict between 8–18
dB/km additional atmospheric attenuation [3]. Precipi-
tation also decreases cross-polarization discrimination
(XPD), reducing the benefits of the extra dimension
afforded by antenna polarization [8]. The erosive
effects on signal energy described above suggest that
International unlicensed spectrum around 60 GHz.
60G systems will have to compensate for lower
received signal energy, and that outdoor systems may
be infeasible for communication over distances beyond
a few kilometers.
2.2 Material Attenuation
The attenuation experienced by 60G electromagnetic
fields through indoor materials is summarized and com-
pared to 2.5 GHz in Table 1. Although not always drastic
or necessarily consistent (see glass attenuation), there is
a basic trend of higher material attenuation observed at
60G. This effect, combined with the increased path loss
contains signals to a single room for 60G indoor wireless
propagation [9]. This allows for increased security and
decreased interference from adjacent networks while at
the same time complicating multi-room coverage.
2.3 Multipath Contributions
Multiple paths in the 60G propagation channel create
multipath interference. The delay and attenuation asso-
ciated with each multipath component corresponds to
path length differences due to surface reflections, scat-
tering by small objects, and propagation through differ-
ent mediums. The scattering effect is drastically
reduced since scattering occurs when objects are simi-
lar in dimension to the operating wavelength. Transmis-
sion through most objects is also reduced as a
consequence of the limited ability to penetrate solid
substances [9]. Although these traditional sources of
multipath are diminished, reflection effects are ampli-
fied. Reflection occurs on objects larger than the dimen-
sions of operating wavelength implying that objects
traditionally acting as scattering objects now become
reflectors at 60G. The root mean square (RMS) delay
spread, TRMS , quantifies the temporal spreading effect
(in seconds) of the wireless channel. Here, we repro-
duce the approximated measurements from [10] in
Table 2 for indoor scenarios. As a rule of thumb, a sys-
tem experiencing an RMS delay spread of TRMS , will suf-
fer |fsTRMS 1|symbols of temporal dispersion or
intersymbol interference (ISI) in the wireless channel
given fsas the data symbol frequency. Because 60G sys-
tems will likely operate on very large bandwidth chan-
nels (on the order of GHz) even traditionally
small RMS delays spreads, as in Table 2, pro-
vide appreciable ISI. Hence, as discussed below,
60G wireless communication systems indoors
or in vehicles must employ antenna techniques
and/or complex receiver equalization to elimi-
nate the severe ISI.
2.4 Impact of Antenna Parameters
on Multipath
The selection of transmit and receive antennas
influences the observed multipath at the receiv-
er. Directive antennas can be used to reduce multipath
contributions by limiting the azimuth and elevation angu-
lar range from which radiation is emitted and captured. In
[11] the RMS delay spread was reduced from 18 ns to 1 ns
by switching from an omnidirectional antenna to one
with a 53-dB-beamwidth at the receiver. The polariza-
tion of antennas can also influence propagation. In [12] it
was observed that circularly polarized signals reduce
RMS delay spread values by a factor of 2 over linearly
polarized signals. Consequently, many 60G systems
employ highly directional antennas with circular polariza-
tion to limit the digital equalization of ISI resulting from
excessive multipath. This forces the transmitter and
receiver to somehow “point” to each other in order to
communicate, resulting in undesired additions to medium
access control (MAC) and physical layer functionality.
2.5 Spatial Characteristic of Multipath
The spatial characteristic of multipath is often measured
using angular spread, which is defined with respect to a
mean angle of arrival or departure. An angular spread of
value 1 indicates an observed channel that varies heavily
with azimuth angle at the receiver while 0 indicates a
channel that does not vary with azimuth angle. In [13] the
Material Loss at 60 GHz Loss at 2.5 GHz
Drywall 2.4 (dB/cm) 2.1 (dB/cm)
Whiteboard 5.0 (dB/cm) 0.3 (dB/cm)
Glass 11.3 (dB/cm) 20.0 (dB/cm)
Mesh Glass 31.9 (dB/cm) 24.1 (dB/cm)
Office material attenuation at 60 GHz
and 2.5 GHz [9].
Dimensions (m3) Wall Material TRMS,90%(ns)TRMS ,10%(ns)
24.5 ×11.2 ×4.5 wood 40 45
30 ×21 ×6 rock wool 30 35
43 ×41 ×7 concrete 40 60
33.5 ×32.2 ×3.1 concrete 40 70
44.7 ×2.4 ×3.1 metal 60 80
9.9 ×8.7 ×3.2 metal 40 45
12.9 ×8.9 ×4.0 wood 15 25
11.3 ×7.3 ×3.1 concrete 25 30
Approximate TRMS for indoor scenarios [10]. TRMS <TRMS,x%
for x%of the time.
authors characterized spatial properties of angular
spread. It was discovered that the angular spread typical-
ly measures from 0.3 to 0.8 in indoor environments, sug-
gesting that space-time processing techniques are viable.
Outdoor scenarios, however, have a reduced angular
spread of 0.1 to 0.5. Reflections contribute to the majority
of received multipath and the material of the reflective
element (i.e., wall) is very critical in determining the
angular spread. These angular spread statistics suggest
that, while space-time processing techniques may not be
helpful in outdoor channels, the spatially rich nature of
indoor channels allows 60G systems to take advantage of
recent advances in array processing and multiple-input-
multiple-output processing (MIMO).
2.6 Time Variation in the Channel
The Doppler frequency is proportional to the transmitted
signal frequency and represents the maximum frequency
difference between received signals and transmitted
signals due to mobility of the transmitter, receiver, or
objects in the channel. Hence, increasing the carrier fre-
quency in wireless systems causes proportionally magni-
fied Doppler effects. It follows that the Doppler frequency
for 60G is 10 times that of a 6 GHz system under the same
mobility conditions. Since there is also a proportional
relationship between the Doppler effect and the time
varying nature of the wireless channel, channel informa-
tion must be estimated 10 times more frequently. The
transmitter uses this information in adapting the modula-
tion scheme or transmission mode for increased reliability
and throughput, while the receiver uses this information
in channel equalization. As a result, 60G systems can
expect increased overhead to obtain the channel at the
transmitter through feedback or at the receiver through
training/pilot symbols. This can be particularly troubling
for outdoor and inter-vehicle communications that must
operate under high mobility.
3. Circuit Design Issues
Initially, 60G transceivers were constructed using hetero-
junction transistors in non-standard technologies such as
GaAs and InGaAs due to their superior noise characteris-
tics and power handling capabilities at higher frequen-
cies. For the commercial market that will access the
unlicensed spectrum, such technologies are ill suited due
to limited digital integration, high relative cost, and low
power efficiency. As a result, recently, there is a focus on
silicon-based analog RF and digital circuits. Building a
60G transceiver presents unique challenges for amplifier
design and phase noise reduction, while the silicon tech-
nology scaling presents new considerations for analog
circuit design.
3.1 Amplifier Challenges
It is well known that as the frequency of operation for
transistors in an amplifier circuit increases, the available
effective gain per transistor decreases. Although the
severity of this trend depends on the technology
implemented, it can universally be stated that the design
of 60 GHz power and low noise amplifiers is a gain-limited
challenge. For low-noise amplifiers the limited gain caus-
es more significant noise contributions. Hence, receiver
noise-figure specifications are much more difficult to
accommodate at 60 GHz. For power amplifiers, transis-
tors need to increase in size to provide enough power to
drive radiating devices such as transmit antennas.
Increasing transistor size, however, also decreases the
gain such that the performance of the amplifier is com-
promised. Ideal designs have yet to surface in silicon-
based circuits, largely because the inherently low gain
characteristic of silicon transistors only exacerbates the
already difficult problem.
3.2 Transceiver Architecture Considerations
Standard wireless receivers typically use heterodyne
architectures, as in Figure 2(a), or homodyne architec-
tures, as in Figure 2(b). Heterodyne receivers, after a
coarse filtering operation, translate the modulated signal
to an intermediate frequency where a higher precision
channel-select filter (to remove out-of-band components)
is easier to design. The translation from a higher fre-
quency to a lower frequency is accomplished by mixing
the signal with a local oscillator and then low pass filter-
ing to remove imaged components. The homodyne
60 GHz Transceiver Architectures.
receiver removes the intermediate frequency conversion
and converts the received modulated signal directly to
baseband. Direct conversion receivers are popular due to
integration ability in CMOS.
Heterodyne and homodyne receivers, when applied to
60G systems, experience aggravated phase noise effects.
Oscillator signals, like those used for mixing at the trans-
mitter and receiver, are typically derived from a refer-
ence oscillator. A multiplier circuit scales this reference
to the desired oscillator signal frequency. Reference
oscillator phase noise amounts to variability of the oscil-
lator’s signal frequency with time. The phase noise effect
is random and there currently exists no way to correct
the problem in traditional transceivers, aside from fre-
quency stabilization, which is largely unsuccessful [14].
It is possible to include better reference oscillators, but
this significantly increases the analog design cost.
Assuming the same reference oscillator, 60 GHz signals
suffer from phase noise that is 10 times greater when
compared to unlicensed wireless systems below 6 GHz.
This effect leads to degraded signal quality and has
proven to be a major limiting factor for the production of
low-cost 60 GHz radios [15].
3.3 Millimeter-wave Silicon Analog Circuits
Current bipolar transistor technology such as 120 nm
silicon-germanium BiCMOS is capable of 60G transceiver
design [16]. Bipolar technologies have superior gain and
noise properties compared to CMOS. Even with the
impressive performance and integration displayed by
bipolar silicon technology, however, the increased power
efficiency, the increased integration, and reduced cost of
a CMOS solution is attractive. Chew et al previewed
CMOS implementations of 60G radios [17]. At that time,
180 nm technology was on the verge of becoming 60 GHz
capable. 135 nm and 90 nm CMOS technology has subse-
quently surfaced (and soon 65 nm), encouraging research
into the design of 60G CMOS transceiver components for
evaluating the potential of 60 GHz CMOS radios [5]. Here
we highlight some of the issues with the design of 60G
CMOS radios:
In general, parasitic elements of tran-
sistors contribute to reduced high-fre-
quency performance. At 60 GHz,
where performance optimization
needs to be finely tuned, the role of
parasitics is magnified. In particular,
resistive parasitics due to gate resis-
tance necessitate finger widths be
optimized during layout to reduce this
parasitic effect [5].
Design rules for CMOS at higher fre-
quencies must incorporate microwave
techniques to account for traveling
wave delay since the operating wave-
length is on the order of circuit dimensions. As a
result, passive elements are often realized using trans-
mission line techniques.
It may occur that CMOS power amplifiers are unable to
accommodate the desired output power. This results
in three choices: a power combining circuit, an exter-
nal power amplifier, or using an antenna array to spa-
tially distribute the signal.
4. Digital Modulation at 60G
Modulation for 60G digital wireless communication must
consider all of the facets of 60 GHz wireless systems
including the channel characteristics, antenna configura-
tions, circuit limitations, and the nature of the data traffic.
Unfortunately, there is not and cannot be a clear choice
for the best modulation scheme at 60G. OFDM, constant
envelope modulation, and linear single carrier modula-
tion are potentially applicable since all offer advantages
to the 60G wireless system, but in different situations.
Like most designs, the modulation choice results from a
consideration of design tradeoffs as detailed in this sec-
tion and summarized in Table 3.
4.1 Orthogonal Frequency Division Multiplexing
Orthogonal frequency division multiplexing (OFDM) is a
digital modulation scheme that has nice equalization
properties. By representing the information bearing ele-
ments in the frequency domain (with an IFFT at the
transmitter and a cyclic prefix with FFT operation at the
receiver) the OFDM system is able to send information
over approximately frequency flat components of a fre-
Scheme Advantages Disadvantages
CE/CPM Maximum power efficiency Poor spectral efficiency;
high complexity receiver
OFDM High spectral efficiency; Sensitive to phase noise;
simple transmitter and poor power efficiency;
receiver designs; flexible added complexity due
frequency allocation to coding and IFFT
Linear SC Simple transmitter and Non-ideal spectral
receiver; performance efficiency; non-ideal
vs. efficiency compromise power efficiency
Modulation Strategies Summary.
quency selective channel. For severely frequency selec-
tive channels (as with the large bandwidth channels for
high data rate applications in 60G) the total complexity
of OFDM to eliminate ISI is less than half that of single
carrier time-domain equalization [4]. OFDM also offers
high spectral efficiency when adapting the power and
signal constellation over each frequency flat component
of the frequency selective channel. Finally, by selectively
activating or nulling subcarriers, OFDM is easily adapted
to different bandwidths, making its application very
OFDM, however, suffers from many drawbacks that
complicate its application at 60 GHz. The time domain
transmitted signal is observed to have large “peaks” when
compared to average power values over the OFDM sym-
bol (i.e., a large peak to average power ratio (PAPR)). To
maintain linearity, ordinary transmitters must limit out-
put power levels leading to less efficiency in terms of
power consumed (resulting in shorter battery life) and
power transmitted (resulting in shorter range). To enable
operation at a higher average power, more expensive
power amplifiers are employed, increasing hardware
costs in OFDM systems. OFDM systems are also severely
susceptible to frequency offsets culminating in higher
design costs for synchronization. Consequently, phase
noise will trouble OFDM implementations to a higher
degree. Finally, although OFDM enables simple equaliza-
tion, it will require significant error control coding to pro-
tect against frequency selective fades. While OFDM is
desirable for its equalization properties and spectral effi-
ciency, 60G OFDM transceivers are difficult to design
given the phase noise and amplifier limitations at 60 GHz.
Additionally, OFDM does not allow for simple
coding/decoding methods for reducing complexity in
large bandwidth 60G frequency selective channels.
4.2 Constant Envelope Modulation
Constant envelope modulation (CEM) transmits a signal
with the information-bearing element contained entirely
within its phase. CEM is ideal in terms of power efficiency
since its constant magnitude baseband signal does not
suffer from nonlinear distortion. CEM signals can operate
in the nonlinear saturation region of the power amplifier
at the transmitter. One specific and popular CEM imple-
mentation is continuous phase modulation (CPM) where
the phase is a continuous function of time, creating a
bandwidth efficient signal. CEM and CPM systems have
their own selection of drawbacks. From a capacity per-
spective, CEM and CPM systems have a lower achievable
throughput, especially for high SNR [18]. In terms of
implementation, optimal non-differential receiver and
equalization structures for CPM systems can be highly
complex since CPM signals are differentially encoded at
the transmitter. Frequency domain equalization for CPM
signals is successful in reducing receiver complexity.
Even with this reduced complexity, however, as the con-
stellation size grows, equalization quickly becomes com-
plex [19]. CEM systems that operate with differential or
symbol-by-symbol detectors are less complex, but will be
highly sensitive to phase noise effects and multipath.
Consequently, although CEM eases amplifier design at
60G by its linearity independence, the susceptibility of
higher-order CEM receivers to phase noise, the subopti-
mal spectral efficiency of CEM signals, and the complexity
of CPM receivers suggest that only low-order CEM (such
as PSK) or CPM techniques (such as MSK) will find any
application at 60G.
4.3 Linear Single Carrier Modulation
Single carrier (SC) systems implemented with linear
modulation (e.g., QAM and PAM constellations) offer a
good compromise for many of the qualities discussed in
this section. SC systems, while not necessarily constant
envelope, display better PAPR values than OFDM. With
ISI equalization, linear SC receivers do not have to
account for memory, making its complexity much less
than CPM. Various equalization algorithms can be imple-
mented, although the complexity of time-domain equal-
ization will exceed that of OFDM for severely frequency
selective channels. For severely frequency selective
channels (like the 60 GHz indoor channel), it is best
served to use frequency domain equalization (FDE) for
SC systems such that the complexity and performance is
comparable to OFDM. Finally, because linear SC systems
usually send information using the amplitude and phase
of the symbol, they are more robust to phase noise than
CEM constellations of the same order. The choice of lin-
ear modulated single carrier systems offers a good com-
promise for power efficiency, spectral efficiency, and
receiver complexity while at the same time displaying
phase noise tolerance that is desirable for 60G systems.
OFDM or CEM, however, may be preferred over linear SC
modulation if maximal spectral or power efficiency is
desired, respectively.
4.4 Space-Time Processing
Space-time processing is used in conjunction with the
modulation techniques discussed above to improve
performance [25]. The measured spatial properties of the
60 GHz indoor channel and the small dimensions of 60G
antennas suggest that space-time processing techniques
are suitable for 60G indoor systems. Space-time process-
ing falls into two distinct categories: diversity and multi-
plexing. Diversity techniques, such as digital
beamforming (not to be confused with beam steering dis-
cussed later in the paper) and space-time coding, exploit
spatially selective fading to improve the received signal
energy. Spatial multiplexing takes advantage of the inde-
pendent nature of spatially uncorrelated channels to
increase effective throughput. An advanced space-time
processing solution could enable high spectral efficien-
cies for 60G systems as well as reduce the fading margin
in the link budget. Unfortunately, because 60G channels
provide unparalleled bandwidths, complex digital space-
time techniques on gigabit systems will likely have to wait
until digital technology scales accordingly. Simple diversi-
ty techniques such as delay diversity, antenna selection,
and transmit/receive combining, however, may be
applied in first generation 60G systems.
5. Potential Applications
Despite the availability of 60G bandwidth, it is currently
not utilized to a sizable measure of its full potential. While
60G systems have attracted mobile broadband and cellu-
lar systems with the potential of high data rates, the
range restrictions at 60G limit such an application. Conse-
quently, the interest in 60G for cellular data delivery has
waned. Fixed wireless access, wireless local area net-
works, wireless personal area networks, portable multi-
media streaming, and vehicular networks, however, are
all applications that will likely find application at 60 GHz
due to the bandwidth offered. To what extent and in what
capacity these applications are utilized will be deter-
mined by the ability of designers to overcome 60G chan-
nel and transceiver circuit limitations.
5.1 Mobile Broadband
The emergence of current EV-DO and UMTS networks and
next generation 3GPP-LTE, WiMax and iBurst networks
have provided a competitive market for mobile broad-
band data delivery. Mobile broadband services are
expected to provide data outdoors and indoors, reliably,
to users at distances up to several kilometers. 60G sys-
tems, however, cannot accommodate this range except
for line-of-sight (LOS) scenarios with highly directive
antennas due to losses attributed to the high carrier fre-
quency, atmospheric, and precipitative effects. This was
observed by IEEE 802.16d, a precursor to WiMax, which
considered mobile broadband delivery up to 66 GHz, but
due to the short range observed, its sequel (IEEE 802.16e,
of which WiMax is based) focused on operating frequen-
cies to below 11 GHz. Although the large bandwidth
afforded 60G systems is desirable for mobile broadband,
the range restrictions do not allow 60G to compete with
lower frequency systems.
5.2 Fixed Wireless Access
60G systems exist for supporting FWA installations of
gigabit data delivery along an LOS path. Transmission
ranges on the order of a kilometer are possible if very
high-gain antennas are deployed. This application, while
viable, does not press the commercial market and indi-
vidual proprietors are already providing solutions. Physi-
cal layer designs must include expensive transceivers and
microwave components to provide reliability and maxi-
mize range, resulting in bulky equipment. Furthermore, to
provide robust communications, modulation schemes
need to be simple and utilize low order constellations.
BridgeWave Communications, for example, provides 60G
wireless back-haul products with 0.6beamwidth anten-
nas that deliver 1.25 Gbps, reliably, using BFSK modula-
tion up to 2.38 km. High data rate FWA products will
continue to find 60G very attractive except for scenarios
where LOS operation cannot be accommodated or when
longer range is needed.
5.3 Wireless Local Area Networks
Presently, wireless local area networks (WLANs), which
largely carry computer network data and Internet traffic,
have been the most popular wireless application of unli-
censed spectrum. Next generation devices that operate
under the IEEE 802.11n standard have the ability to oper-
ate at hundreds of megabits per second. The key feature
of 60G technology for WLANs is the capability to provide
gigabits per second of throughput, i.e. gigabit Ethernet.
Due to the increased attenuation of 60G signals and the
decreased propagation through materials, it will take con-
siderable effort to develop 60G WLANs that communicate
over NLOS links. The lack of 60G communication between
rooms indoors will necessitate 60G repeaters for typical
WLAN installations. Some vendors have proposed hybrid
2.5/5/60 GHz WLAN solutions that use lower frequencies
for normal operation and 60G when there exists a short-
range LOS path for high-speed operation. Therefore,
while 60G will likely find applications in WLAN at some
point in the future, it is not expected to immediately drive
60G technology to the consumer market due to range and
NLOS propagation restrictions. Future WLAN designers,
as in the Very High Throughput study group of IEEE
802.11 [28], still consider millimeter-wave and 60G WLAN
promising due to the large unlicensed bandwidth offered.
5.4 Wireless Personal Area Networks
Increasing the data-rate of legacy wireless personal area
networks (WPANs) such as Bluetooth provides the main
driving force for 60G solutions in the commercial arena.
The IEEE 802.15.3c international standard will provide reg-
ulation for the short-range data networks (10 m) over
60G wireless channels. Although this standard is still in
the development phase the task group has set out to pro-
vide, in its first phase, 2 Gbps mandatory and 3 Gbps
optional wireless data transfers to support cable replace-
ment of USB, IEEE 1394, gigabit Ethernet, and multimedia
delivery. In the United States, ultrawideband (UWB) has
the ability to provide the hundreds of megabits per
second needed for next generation PANs in frequencies
ranging from 3–10 GHz [26]. Unfortunately UWB communi-
cation suffers from two major problems. The first problem
with UWB communication is that UWB spectrum is not
commensurate worldwide. Europe, for example, only pro-
vides a fraction of the available UWB spectrum in the Unit-
ed States. Thus, while UWB is a viable technology for
WPANs it does not provide the worldwide market that
made WLANs so successful. Second, UWB does not supply
high enough data rates to support cable replacement for
some next generation applications. UWB under the WiMe-
dia multi-band OFDM standard only supports 480 Mb/s at
its highest rate. Given the restrictions placed on UWB in
terms of bandwidth and power this is likely within a factor
of two of the upper limit. In order to achieve multi-gigabit-
per-second wireless communication, it seems that 60 GHz
is the only foreseeable solution in the near future.
5.5 Multimedia Streaming
Cable replacement for high rate multimedia streams
such as the high-definition multimedia interface (HDMI)
provides an important potential application of 60G wire-
less technology. Current wireless HDMI products radiate
in the 2.5 GHz and 5 GHz unlicensed spectrum where
bandwidth is limited. As a result these systems imple-
ment either lossy or lossless compression, which signifi-
cantly adds component and design cost, digital
processing complexity, as well as product size. Off the
shelf, retail wireless HDMI products currently available
exceed 100 US dollars for a bulky set-top box. If 60G
transceivers are able to achieve in excess of 5 Gbps it
will enable cost-effective wireless HDMI solutions with
tight integration to support even the most demanding
1080p HDTV streams.
5.6 Vehicular Applications
60G vehicular applications are partitioned into three class-
es: Intra-vehicle wireless networks, inter-vehicle wireless
networks, and vehicular radar. Intra-vehicle networks are a
subset of WPANs that exist entirely within a vehicle. Of this
subset, broadband communication within an automobile
or aircraft [20] has garnered interest for removing wired
connections of vehicular devices (e.g., wires between con-
sole dashboard DVD player and backseat displays) as well
as multimedia connectivity of portable devices inside the
vehicle (e.g., MP3 players, laptops, etc.). The 60 GHz carri-
er frequency is especially attractive for intra-vehicle com-
munications due to its containment within the vehicle and
decreased ability to penetrate and interfere with other
vehicular networks. Inter-vehicle networks are significantly
different than intra-vehicle networks mainly because they
operate in an outdoor propagation environment. Automo-
bile communication for delivery of traffic information and
range extension of mobile broadband networks has also
received significant interest [21]. Unfortunately, realization
of inter-vehicle communication at 60G is more challenging
than other 60G applications due to the high Doppler, which
increases overhead for maintaining links, and low range,
which limits the distance between automobiles of a con-
nected network. Therefore, while the large amount of
bandwidth available is attractive for inter-vehicle net-
works, it is unlikely to be an early application of 60G tech-
nology. The last class of vehicular networks, vehicular
radar [22], have already been deployed at millimeter-wave
frequencies albeit not within the aforementioned unli-
censed 60G spectrum. Nevertheless, 60G has attracted
interest for adaptive cruise control in cars as well as auto-
motive localization [23]. 60G radar is particularly effective
at resolving small objects due to the millimeter wavelength
of 60G signals.
6. IEEE 802.15.3c Standard
The IEEE 802.15.3c standard, when completed, will pro-
vide the first widespread international physical layer
framework to support consumer 60G WPANs. In
September of 2007 Task Group 3c in the IEEE 802.15
working group narrowed down the selection of its 60G
physical layer into two proposals [27]. Many contribut-
ing bodies including Matsushita, Philips, Korea Universi-
ty, the Electronics and Telecommunications Research
Institute (ETRI), the Georgia Electronic Design Center
(GEDC), Decawave, and Astrin Radio provided support
for Proposal #1, spearheaded by the National Institute of
Information and Communications (NICT) in Japan. Pro-
posal #2, led by Tensorcom, includes contributions from
France Telecom, Innovations for High Performance (IHP)
Microelectronics, LG Electronics, Matsushita, Sony,
Intel, Sibeam, and Samsung Electronics. These two pro-
posals, while containing notable differences, still offer a
clear view of the yet-to-be-finalized physical layer stan-
dard. This section provides a general summary of the
two proposals.
6.1 Spectrum Occupancy
60G unlicensed spectrum, as noted in Figure 1, is incon-
sistent internationally. To encompass all available unli-
censed frequencies both proposals divide nearly 9 GHz of
spectrum starting at 57.24 GHz and ending at 65.88 GHz
into four 2.16 GHz channels. The Nyquist bandwidth of
both proposals is 1.632 GHz, leaving roughly 250 MHz of
guard bandwidth on each side to prevent spectral leak-
age. Proposal #1 also allows for a half-rate channel, which
operates at the same center frequency, but with half the
Nyquist bandwidth.
6.2 Transmission Modes
Both proposals share three basic transmission modes:
Common Mode, Single Carrier (SC) Mode, and OFDM
Mode. The Common Mode is used for channel scanning
as well as providing a low rate communication mode.
Channel scanning consists of the transmission and recep-
tion of beacons to negotiate a link between two 60G
devices. Both the SC and OFDM Mode occur only after the
Common Mode operation is complete and a 60G wireless
link is established. The SC Mode and OFDM Mode are fur-
ther classified according to the throughput delivered:
Low Rate, Medium Rate, High Rate. Therefore, there are a
large number of potential modes, allowing providers to
consider the tradeoffs discussed in Section IV.
6.3 Modulation
The modulation for each mode varies between Proposal
#1 and Proposal #2, although not significantly. Rather
than providing an exhaustive list of the proposed modula-
tion in each transmission mode and each proposal, this
section will summarize the common modulation trends
that will likely represent the combined proposal. The
reader is encouraged to view the proposals available on
the Task Group 3c web site [27] for more detail. The mod-
ulation selection across both proposals is briefly summa-
rized in Table 4. Common Mode transmission utilizes
power efficient MSK for reliable, low complexity commu-
nication in the presence of channel impairments, such as
the intrinsically large path loss, and hardware impair-
ments, such as nonlinear power amplifiers. The Common
Mode also implements a low-complexity Golay code for
spreading the signal by a factor of 32 in Proposal #1 and
64 in Proposal #2. This spreading gain allows the
Common Mode to be tolerant to interference from other
networks as well as operate in low SNR environments.
For communication beyond the base rate of approxi-
mately 50 Mbps provided by the Common Mode, the SC
Mode is preferred due to its lower complexity, tolerance
to phase noise, and tolerance of nonlinear power ampli-
fiers. Forward error correction and spreading gain are
varied to provide quantized levels of physical layer
throughput depending on the channel and hardware
impairments observed. The mandatory rates required in
SC Mode will offer between 2–3 Gbps. OFDM Mode, which
utilizes a size 512 FFT, will likely be relegated to an
optional mode in the final standard. Although OFDM suf-
fers from sensitivity to phase noise and nonlinear power
amplifiers, the spectral efficiency and ISI immunity of
OFDM encouraged both proposals to include this mode.
Given the modes provided in the proposals future 60G
systems can achieve up to 6 Gbps throughput as trans-
ceiver design improves. Both OFDM and SC modes use a
unified frame format, meaning that FDE is supported for
both SC Mode and OFDM Mode.
7. Developing Technologies
The future of 60G systems will be shaped by emerging
technologies to enable advanced techniques in the wire-
less transceiver. In this section we discuss two examples
of emerging technologies that will have a large impact on
the progression of 60G wireless design.
7.1 Steerable Beam Antennas
As previously discussed, high-gain antennas may be
implemented to overcome fading margins in the link bud-
get. As a result of the inherent “pointing” problems asso-
ciated with these high gain antennas, many designers
have proposed steerable beam antennas [24]. Such anten-
na configurations discover the best direction to point
through a searching algorithm and then either mechani-
cally alter the configuration of the antenna (as in micro
electrical mechanical systems (MEMS)), or use several
antenna elements to construct a phased array with opti-
mized radiation patterns. While such configurations have
been demonstrated, it is yet to be observed in a practical
commercial transceiver with a small form-factor required
for WPAN or WLAN devices. If such technologies become
practical, it will help enable 60G systems that do not rely
on LOS links.
7.2 Self-Heterodyne Transceivers
To bypass the phase noise problem it was observed that
by transmitting the local oscillator signal with the modu-
lated signal, mixing could be accomplished by multiplying
the received local oscillator signal and the received mod-
ulated signal. Since they both suffer from the same phase
Transmission Mandatory Optional
Mode Components Components
Common CPM; large N/A
spreading gain
SC: Low Rate CPM; large CPM or CEM;
spreading gain variable
spreading gain
SC: Med Rate N/A QPSK or 8-QAM
SC: High Rate QPSK 8-PSK, 8-QAM,
or 16-QAM
OFDM: Med Rate N/A QPSK or 16-QAM
OFDM: High Rate N/A 16-QAM or
IEEE 802.15.3c Modulation Preview.
noise effects, the noise is canceled out. This design
(Figure 2(c)) is referred to as a self-heterodyne receiver.
This technique allows for cheap reference oscillators
with poor phase noise performance. Unfortunately, this
design has four major disadvantages. First, the local oscil-
lator that is transmitted takes up bandwidth. Second, the
local oscillator and the modulated signal have to be sepa-
rated in the frequency domain by at least the bandwidth
of the modulated signal. Third, the local oscillator that is
transmitted is very sensitive to interference and multi-
path effects. As a result, there is a different source of sig-
nal degradation corresponding to mixing with a distorted
local oscillator. Finally, and perhaps most importantly,
the local oscillator signal received over-the-air is much
weaker than local oscillator signals supplied on typical
heterodyne receivers. Hence, RF self-product terms
become much more significant in the mixer output of a
self-heterodyne receiver, causing increased received sig-
nal distortion. Despite these drawbacks, self-heterodyne
architectures have received interest [14], especially for
robustness to phase noise.
8. Conclusion
The large quantity of unlicensed bandwidth internation-
ally available at 60 GHz provides system designers with
a multitude of options for wireless communications
application. Specific challenges for 60G design include
heavy large-scale attenuation due to the increased
carrier frequency, substantial atmospheric absorption
for communication over large distances, increased
phase noise for transceivers, and limited gain ampli-
fiers. The application-space for 60G systems must con-
sider these challenges. While mobile broadband
systems may not be feasible, there are still promising
applications for WLANs, WPANs, FWA, vehicular net-
works, and multimedia delivery to take advantage of the
large bandwidth over short distances. The modulation
choice offered, as displayed in the IEEE 802.15.3c pro-
posals, will depend on a tradeoff between digital com-
plexity, power efficiency, phase noise sensitivity, and
spectral efficiency. The best implementation will depend
on which tradeoff best suits the design given the band-
width offered, the antenna parameters, and transceiver
characteristics. Developing technologies such as steer-
able antennas and self-heterodyne transceivers could
help shift these tradeoffs.
[1]S.K. Yong and C.-C. Chong, “An overview of multigigabit wireless through
millimeter wave technology: Potentials and technical challenges,” EURASIP
Journal on Wireless Communications and Networking, vol. 2007, 2007.
[2] M. Chelouche and A. Plattner, “Mobile broadband systems (MBS): Trends and
impact on 60 GHz band MMIC development,” Electronics & Communication Engi-
neering Journal, vol. 5, no. 3, pp. 187–197, 1993.
[3] F. Giannetti, M. Luise, and R. Reggiannini, “Mobile and personal communications
in 60 GHz band: A survey,” Wirelesss Personal Comunications, vol. 10, pp. 207–243,
[4] P. Smulders, “Exploiting the 60 GHz band for local wireless multimedia access:
Prospects and future directions,” IEEE Communications Magazine, vol. 40, no. 1,
pp. 140–147, 2002.
[5] C. Doan, S. Emami, D. Sobel, A. Niknejad, and R. Brodersen, “Design considera-
tions for 60 GHz CMOS radios,” IEEE Communications Magazine, vol. 42, no. 12,
pp. 132–140, 2004.
[6] M. Karkkainen, M. Varonen, P. Kangaslahti, and K. Halonen, “Integrated amplifi-
er circuits for 60 GHz broadband telecommunication,” Analog Integrated Circuits
and Signal Processing, vol. 42, pp. 37–46, 2005.
[7] N. Guo, R.C. Qiu, S.S. Mo, and K. Takahashi, “60 GHz millimeter-wave radio: Prin-
ciple, technology, and new results,” EURASIP Journal on Wireless Communica-
tions and Networking, vol. 2007, 2007.
[8] D. Rogers, “Propagation considerations for satellite broadcasting at frequencies
above 10 GHz,” IEEE J. Select. Areas Commun., vol. 3, no. 1, pp. 100–110, 1985.
[9] C. Anderson and T. Rappaport, “In-building wideband partition loss measure-
ments at 2.5 and 60 GHz,” IEEE Trans. Wireless Commun., vol. 3, no. 3, pp. 922–928,
[10]P. Smulders and A. Wagemans, “Wideband indoor radio propagation measure-
ments at 58 GHz,” Electronics Letters, vol. 28, no. 13, pp. 1270–1272, 1992.
[11]T. Manabe, Y. Miura, and T. Ihara, “Effects of antenna directivity and polariza-
tion on indoor multipath propagation characteristics at 60 GHz,” IEEE J. Select.
Areas Commun., vol. 14, no. 3, pp. 441–448, 1996.
[12]T. Manabe, K. Sato, H. Masuzawa, K. Taira, T. Ihara, Y. Kasashima, and K.
Yamaki, “Polarization dependence of multipath propagation and high-speed
transmission characteristics of indoor millimeter-wave channel at 60 GHz,” IEEE
Trans. Veh. Technol., vol. 44, no. 2, pp. 268–274, 1995.
[13]H. Xu, V. Kukshya, and T. Rappaport, “Spatial and temporal characteristics of
60-GHz indoor channels,” IEEE J. Select. Areas Commun., vol. 20, no. 3, pp.
620–630, 2002.
[14] Y. Shoji, K. Hamaguchi, and H. Ogawa, “Millimeter-wave remote self-heterodyne
system for extremely stable and low-cost broad-band signal transmission,” IEEE
Trans. Microwave Theory and Techniques, vol. 50, no. 6, pp. 1458–1468, 2002.
[15]D. Cabric, M.S.W. Chen, D.A. Sobel, S. Wang, J. Yang, and R.W. Brodersen,
“Novel radio architectures for UWB, 60 GHz, and cognitive wireless sys-
tems,” EURASIP Journal on Wireless Communications and Networking,
vol. 2006, 2006.
[16]S. Reynolds, B. Floyd, U. Pfeiffer, T. Beukema, J. Grzyb, C. Haymes, B. Gaucher,
and M. Soyuer, “A silicon 60 GHz receiver and transmitter chipset for broad-
band communications,” IEEE J. Solid-State Circuits, vol. 31, no. 12, pp. 2820–2830,
[17]K. Chew, S.-F. Chu, and C. Leung, “Driving CMOS into the wireless communica-
tions arena with technology scaling,” in IEEE Conference on Custom Integrated
Circuits, San Diego, CA, 2001, pp. 571–574.
[18]K. Yu and A. Goldsmith, “Linear models and capacity bounds for continuous
phase modulation,” in proceedings of IEEE International Conference on Communi-
cations, vol. 2, 2002, pp. 722–726.
[19]J. Tan and G. Stuber, “Frequency-domain equalization for continuous phase
modulation,” IEEE Trans. Wireless Commun., vol. 4, no. 5, pp. 2479–2490, 2005.
[20]M. Peter, W. Keusgen, A. Kortke, and M. Schirrmacher, “Measurement and
analysis of the 60 GHz in-vehicular broadband radio channel,” in proceedings of
IEEE Vehicular Technology Conference, Sept., 2007.
[21]H. Bischl and W. Schäfer, “The 60 GHz mobile-to-mobile radio channel—fading
statistics and estimated packet error rates,” in proceedings of IEEE Vehicular
Technology Conference, June, 1994.
[22]J. Ruoskanen, P. Eskelinen, and H. Heikkila, “Millimeter wave radar with clutter
measurements,” IEEE AES Magazine, vol. 18, pp. 19–23, 2003.
[23]H.-J. Fischer, “Digital Beacon vehicle communications at 61 GHz for interactive
dynamic traffic management,” 8th International Conference on Automotive Elec-
tronics, London, 1991.
[24]K. Chang, M. Li, T.-Y. Yun, and C.T. Rodenbeck, “Novel low-cost beam-steering
techniques,” IEEE Trans. Ant. Prop., vol. 50, no. 5, pp. 618–627, 2002.
[25]R.W. Heath, Jr. et al. “Advanced wireless: Space-time communication,” Univer-
sity of Texas Course Text, 2007.
[26]J. del Prado Pavon, N. Sai Shankar, V. Gaddam, K. Challapali, and C.-T. Chou,
“The MBOA-WiMedia specification for ultra wideband distributed networks,”
IEEE Communications Magazine, vol. 44, no. 6, pp. 128–134, 2006.
[27]“IEEE 802.15 WPAN Millimeter Wave Alternative PHY Task Group 3c,” [Online]:, Sept., 2007.
[28]Status of Project IEEE 802.11 VHT Study Group,” [Online]:, Sept., 2007.
... The unlicensed spectrum at 60 GHz supports high rates, and many researchers are using the 60 GHz frequency because it also provides license free communication and improve efficiency [8][9][10][11][12]. Hence, for our investigation, the signal was deployed at 60 GHz and a two-element uniform array antenna array with half-length spacing was used to provide the MIMO diversity technique. ...
... Hence, the performance of dB8 family was much better than that of th family. The simulation performance in terms of BER for the MIMO DWT system was analyzed with different wavelets; the parameters are listed in Table 4. Figure 6 shows a comparisons of the outcomes of the suggested simulation with those analytically obtained using BER Equation (12). The graph demonstrates that the BER values for the SNR range of 6-8 dB was essentially the same as the simulation findings, with very little variance between them. ...
... In order to calculate the average BER for the simulation results given that the data were generated at random, the suggested MIMO diversity technique with wavelet transform was iterated a number of times. Figure 6 shows a comparisons of the outcomes of the suggested simulation with those analytically obtained using BER Equation (12). The graph demonstrates that the BER values for the SNR range of 6-8 dB was essentially the same as the simulation findings, with very little variance between them. ...
Full-text available
Utilizing antenna diversity techniques has become a well-known approach to improve the performance of wireless communication systems. Multiple antenna arrays with half-length spacing, such as a uniform linear array (ULA), have been taken into consideration. Since 60 GHz is an unlicensed frequency band and ideal for local propagation, it is where the technology is being used. The transmitter and receiver both accomplish QAM modulation and demodulation. The performance in terms of bit error rate (BER) was tested in MATLAB simulation software for all antenna diversity scenarios: the single input and single output (SISO) DWT, multiple input and single output (MISO) DWT, single input and multiple output (SIMO) DWT, and multiple input and multiple output (MIMO) DWT. The MIMO DWT was shown to be the best of them. The performance of MIMO OFDM using various wavelets was also simulated, and the performance of the Haar wavelet transform was 2 dB better than that of the other wavelet transform. Compared to simulation results, the analytical results showed good agreement with little discrepancy.
... De plus, le signal CPM présente une continuité de phase qui se traduit par un spectre avec un lobe principal plus étroit et des lobes secondaires plus faibles, ce qui permet une utilisation plus efficace de la bande passante (modulation spectralement efficace). Les avantages des CPM sont donc : enveloppe constante, efficacité énergétique et efficacité spectrale permettent à la modulation CPM d'être largement utilisée dans différentes applications, telles que les communications mobiles [44], les communications millimétriques [12], les communications militaires [8]. De plus, les signaux CPM ont également été retenus dans des applications telles que considérés récemment pour les applications de télémétrie [58] et les communications de type machine (IOT) dans la 5ème génération (5G) de radiocommunication [10]. ...
... Moreover, CPM exhibits the phase continuity results in a spectrum with a narrow main lobe and lower sidelobes [5], allowing for more efficient bandwidth usage (Spectral efficient modulation). These advantages: constant envelope, power efficiency, and spectral efficiency allow CPM to be widely utilized in different applications, such as mobile communications [44], millimeter communications [12], military communications [8]. Moreover, the CPM signals are also recently considered for telemetry applications [58] and machine type communication in the 5th generation (5G) of radio communication [10]. ...
... , r Js conditioned on the transmitted signal s i (t), where J s is the expansion of r(t) and s i (t) to J s -dimensional signal space. The detailed analysis is not given, but the final expression of (1.11) is [1] : 12) where N 0 is the power spectral density of the AWGN channel. It can be observed from (1.12) that the value of the density depends on only one quantity that relates to the signal set, j (r j − s ij ) 2 . ...
Full-text available
In this PhD thesis, we investigate the single-sideband frequency shift keying (SSB-FSK), a continuous phase modulation (CPM) scheme having, by essence, the original feature of the single-sideband (SSB) spectrum. First, we present the origin of the signal from quantum physics. Then, we propose a simplified Maximum likelihood sequence detection (MLSD) detector for conventional CPM schemes based on the rearrangement shown in the SSB-FSK signal model. To fully exploit the SSB-FSK performance, we examine the signal error probability, bandwidth occupancy, and receiver complexity. Since different performance metrics are considered, we employed a multi-objective optimization to achieve new SSB-FSK schemes that outperform conventional CPM schemes.Moreover, we propose a solution to simplify the complexity of SSB-FSK signals using the pulse amplitude modulation (PAM) decomposition. The PAM pulses were achieved from an algorithm we developed. Furthermore, we offer an optimum generic training sequence for the joint estimation of symbol timing, frequency offset, and carrier phase for burst mode synchronization. The training sequence was obtained using the Cramér-Rao bounds.
... Microstrip antennas are widely used in the microwave frequency region due to their important advantages of being low profile, planar, easy to fabricate, easy to feed, and low cost [1][2][3]. These advantages have made the microstrip antennas attractive for many applications, including mobile communications, global positioning system (GPS), satellite communications, radar systems, remote sensing, biological imaging, telemetry, and others [4][5][6][7][8]. Microstrip antennas are usually used in the ultra-high frequency (UHF) band or higher, up through millimetre-wave frequencies, with microwave applications being the most common [9]. ...
... To calculate the dielectric quality factor Q d , the dielectric loss is included with the conductor loss and the radiation loss is turned off, i.e. the metallic components of the SIW cavity are perfectly conducting and no aperture is present. Equation (6) implies that Q d is only determined by the dielectric loss tangent. Figure 9b verifies that Q d is constant when the substrate thickness h is varying. ...
Full-text available
A near‐field planar sensor fabricated from a substrate integrated waveguide (SIW) cavity resonator is presented. The SIW cavity resonator is a modification of a rectangular microstrip antenna. The rectangular microstrip antenna radiates from two radiating edges that produce far‐field radiation, which is undesired for near‐field sensing. To suppress the radiation from the edges, the microstrip antenna is modified to have conducting vias that short all four edges of the patch to the ground plane. A circular hole is placed on the patch surface in the middle of the patch to form a sensing aperture. The field is thus confined inside the cavity with leakage only allowed through a small aperture, which is used for sensing surrounding objects in the vicinity of the aperture. This cavity resonator operates in the TM21 mode of the SIW cavity. Full‐wave simulations are performed and the results are consistent with the theoretical analysis as well as CAD formulas that are derived. The performance of the sensor as a near‐field sensing device and as a near‐field imager is explored.
... For instance, mmWave power amplifiers are usually less efficient due to the very high frequency of operation. Similarly, the design of wideband PAs and low-noise amplifiers (LNAs) at 60 GHz mmWave is also a challenge [137]. Particularly high PA efficiency will help to extend communication range and enhance battery life. ...
Full-text available
Industry 4.0 is a new paradigm of digitalization and automation that demands high data rates and real-time ultra-reliable agile communication. Industrial communication at sub-6 GHz industrial, scientific, and medical (ISM) bands has some serious impediments, such as interference, spectral congestion, and limited bandwidth. These limitations hinder the high throughput and reliability requirements of modern industrial applications and mission-critical scenarios. In this paper, we critically assess the potential of the 60 GHz millimeter-wave (mmWave) ISM band as an enabler for ultra-reliable low-latency communication (URLLC) in smart manufacturing, smart factories, and mission-critical operations in Industry 4.0 and beyond. A holistic overview of 60 GHz wireless standards and key performance indicators are discussed. Then the review of 60 GHz smart antenna systems facilitating agile communication for Industry 4.0 and beyond is presented. We envisage that the use of 60 GHz communication and smart antenna systems are crucial for modern industrial communication so that URLLC in Industry 4.0 and beyond could soar to its full potential.
... The 60 GHz ISM band and its abundance of spectrum represent a great opportunity, not yet well explored, for ultra-high speed and short-range wireless communications. The challenges for its commercial use are different from that of consumer technologies below 6 GHz [1,2], which may influence the slow deployment. The first obstacle to large-scale exploitation is the high free-space path loss that the signal is subjected to and the great sensitivity to blockage. ...
Full-text available
Abstract In this article, antennas for the 60 GHz ISM band designed to be integrated to a new high-frequency, low-cost interposer technology called Membrane-nanowire-Membrane (MnM) are discussed, manufactured, and measured. Also, an antenna characterization system under development at the Microelectronic Laboratory (LME-USP) is introduced, showing promising results for the deployment of mmW systems.
... 2 Sixty gigahertz applications require a high data rate and a high resolution too. 3 This can be achieved partially by directive antennas which demonstrate a reduction in the multipath (delay and attenuation) and the path loss. [4][5][6] There are many investigations dedicated to highly directive antennas for 60 GHz. [6][7][8] Usually, such structures are achieved with antenna array techniques. ...
Full-text available
Parabolic reflectors have very good directivity. However, when put behind a partially reflecting surface, they suffer from destructing in‐phase rays and they experience deteriorated characteristics. In this work we consider fixing this impediment and we enhance the low profile by providing a new approach based on ray optics model. This approach grabs the equations of multiple reflections between the two components to re‐construct a collimated beam in the normal direction of the radiated element. This model is confirmed with a peak simulated directivity of about 28 dB of the new compact parabolic quasi Fabry–Pérot cavity. The highly directive and low profile proposed model is valid for both microwave and mmWave bands (from 5 to 60 GHz). The measured realized gain of the fabricated prototype is compared with a simulated data resulting in a peak of about 25.2 dB.
... Millimeter wave (mmWave) systems enable multigigabit data rates in the 5th generation mobile network (5G) and future wireless cellular communications, but its path loss and penetration loss are much higher than those of present systems [1,2]. Due to its short wavelength, a large number of antennas are allowed to be placed in a small area. ...
Full-text available
Millimeter wave (mmWave) communication and multiple-input multiple-output (MIMO) are two important technologies for future communication systems. Hybrid precoding and combining have been used to reduce the cost and the power consumption of traditional full digital precoding and combining for mmWave MIMO systems. In this paper, we consider a fully-connected hybrid precoding architecture with finite resolution phase shifters in the design. Basically, we first obtain the phases of optimal precoder and combiner, which are obtained through the singular value decomposition (SVD) operation of channel vectors. Then, these phases are used to construct the RF precoder and combiner. After the RF precoder and combiner are achieved, the digital precoder and combiner can be calculated by the least squares solutions. The simulation results show that the proposed algorithms improve the capacity and reduce the complexity compared with the existing orthogonal matching pursuit (OMP)-based algorithm. Besides, an adaptive solution is further proposed to save computational time with competitive performance. With the adaptive solution, the full SVD process is not required for the weighting coefficient updating at every time slot.
Technical Report
Full-text available
Full-text available
The worldwide opening of a massive amount of unlicensed spectra around 60 GHz has triggered great interest in developing affordable 60-GHz radios. This interest has been catalyzed by recent advance of 60-GHz front-end technologies. This paper briefly reports recent work in the 60-GHz radio. Aspects addressed in this paper include global regulatory and standardization, justification of using the 60-GHz bands, 60-GHz consumer electronics applications, radio system concept, 60-GHz propagation and antennas, and key issues in system design. Some new simulation results are also given. Potentials and problems are explained in detail.
Full-text available
There are several new radio systems which exploit novel strategies being made possible by the regulatory agencies to increase the availability of spectrum for wireless applications. Three of these that will be discussed are ultra-wideband (UWB), 60 GHz, and cognitive radios. The UWB approach attempts to share the spectrum with higher-priority users by transmitting at power levels that are so low that they do not cause interference. On the other hand, cognitive radios attempt to share spectra by introducing a spectrum sensing function, so that they are able to transmit in unused portions at a given time, place, and frequency. Another approach is to exploit the advances in CMOS technology to operate in frequency bands in the millimeter-wave region. 60 GHz operation is particularly attractive because of the 7 GHz of unlicensed spectrum that has been made available there. In this paper, we present an overview of novel radio architecture design approaches and address challenges dealing with high-frequencies, wide-bandwidths, and large dynamic-range signals encountered in these future wireless systems.
Full-text available
A 0.13-m SiGe BiCMOS double-conversion super-heterodyne receiver and transmitter chipset for data communica-tions in the 60-GHz band is presented. The receiver chip includes an image-reject low-noise amplifier (LNA), RF-to-IF mixer, IF amplifier strip, quadrature IF-to-baseband mixers, phase-locked loop (PLL), and frequency tripler. It achieves a 6-dB noise figure, 30 dBm IIP3, and consumes 500 mW. The transmitter chip includes a power amplifier, image-reject driver, IF-to-RF upmixer, IF amplifier strip, quadrature baseband-to-IF mixers, PLL, and frequency tripler. It achieves output P 1dB of 10 to 12 dBm, P sat of 15 to 17 dBm, and consumes 800 mW. The chips have been packaged with planar antennas, and a wireless data link at 630 Mb/s over 10 m has been demonstrated. Index Terms—Low-noise amplifier, millimeter-wave integrated circuits, mixer, power amplifier, SiGe, superheterodyne receiver, superheterodyne transmitter, V-band, voltage-controlled oscillator (VCO), 60 GHz.
Conference Paper
Full-text available
An integrated SiGe superheterodyne RX/TX pair capable of Gb/s data rates in the 60GHz band is described. The 6dB NF RX includes an image-reject LNA, a multistage down-converter with on-chip IF filters, a frequency tripler, a PLL, and baseband outputs. The 10 to 12dBm P<sub>1dB</sub>TX achieves 10% PAE in the final stage. It includes a PA, image-reject driver, multistage up-converter with on-chip filters, tripler, and PLL
Conference Paper
Full-text available
In this paper, we present the results of a measurement campaign regarding the 60 GHz in-vehicular wireless channel. The measurements have been performed inside an aircraft passenger cabin by the use of a modular setup covering a bandwidth of 1 GHz. We consider path loss aspects and investigate the time-dispersive nature of the channel. Additionally the influence of an obstructed line-of-sight is analyzed.
Wide frequency bandwidth has been internationally allocated for unlicensed operation around the oxygen absorption frequency at 60 GHz. A power amplifier and a low noise amplifier are presented as building blocks for a T/R-unit at this frequency. The fabrication technology was a commercially available 0.15 m gallium arsenide (GaAs) process featuring pseudomorphic high electron mobility transistors (PHEMT). Using on-wafer tests, we measured a gain of 13.4 dB and a +17 dBm output compression point for the power amplifier at 60 GHz centre frequency when the MMIC was biased to 3 volts Vdd. At the same frequency, the low noise amplifier exhibited 24 dB of gain with a 3.5 dB noise figure. The AM/AM and AM/PM characteristics of the power amplifier chip were obtained from the large-signal S-parameter measurement data. Furthermore, the power amplifier was assembled in a split block package, which had a WR-15 waveguide interface in input and output. The measured results show a 12.5 dB small-signal gain and better than 8 dB return losses in input and output for the packaged power amplifier.
This paper intends to present a summary of the technical issues arising in the exploitation of the 60 GHz mm-wave band for mobile and personal communications. The most significant applications proposed so far are surveyed, with particular emphasis placed on recent experimentation about millimeter-wave propagation for road/railway transportation as well as indoor scenarios. As a case study, the capacity of a (micro-)cellular Code Division Multiple Access (CDMA) network in the 60-GHz band is also evaluated in detail.
Wide frequency bandwidth has been internationally allocated for unlicensed operation around the oxygen absorption frequency at 60 GHz. A power amplifier and a low noise amplifier are presented as building blocks for a T/R-unit at this frequency. The fabrication technology was a commercially available 0.15 μm gallium arsenide (GaAs) process featuring pseudomorphic high electron mobility transistors (PHEMT). Using on-wafer tests, we measured a gain of 13.4 dB and a +17 dBm output compression point for the power amplifier at 60 GHz centre frequency when the MMIC was biased to 3 volts V dd. At the same frequency, the low noise amplifier exhibited 24 dB of gain with a 3.5 dB noise figure. The AM/AM and AM/PM characteristics of the power amplifier chip were obtained from the large-signal S-parameter measurement data. Furthermore, the power amplifier was assembled in a split block package, which had a WR-15 waveguide interface in input and output. The measured results show a 12.5 dB small-signal gain and better than 8 dB return losses in input and output for the packaged power amplifier.
Conference Paper
This paper presents the results of 60 GHz mobile-to-mobile radio channel measurements which were carried out on highways, rural roads and in urban surroundings for distances up to 500 m. Fading statistics concerning the duration of fades and the distribution function of the received power are presented. Furthermore, the measured channel data were used for the simulation of a packet transmission in order to predict the packet error rates and the performance of some error control methods, i.e. time diversity, antenna diversity, forward error correction (FEC) and a code combining method. Selected results of highway measurements for distances between the transmitter and receiver from 200 m up to 500 m are presented. The probability density function of the received signal amplitude shows good agreement with a Rice/Rayleigh-lognormal density. For a transmitter power of 14 dBm, a packet length of 259 bit and BPSK-modulation with 500 kbps the estimated mean packet error rate was less than 10<sup>-2</sup> for distances up to 300 m without additional error control. With antenna diversity as well as with the code combining method the estimated mean packet error rate was less than 10<sup>-2</sup> even for vehicles distances up to 500 m