Dr. Lin-Nan Lee

A Contrarian’s View on
5G Wireless
November 1, 2014
Outlines




Success Factors for a New Standard
Personal View of 5G
Key 5G Challenges
Conclusions
Success Factors for New Standards



Market Needs
Technology Advances
Overall Environment
Market
Technology
Environment
Key Success Factor – Market Needs




2G – Explosive demand of mobile voice calls
3G – Demand of medium-speed (e.g.1G WLAN 802.11 –
2G WLAN 802.11.b), basic wireless Internet Services, (e.g.
e-mail, simple documents, simple information searches,
audio streaming, etc.)
4G – Demand of high-speed data (e.g. 3G WLAN
802.11.g/n), more advanced applications (e.g. video
streaming, web browsing, countless apps.)
5G – Continued growth on Internet traffic and desire to “cut
cord”, new applications (health, connected home,
connected cars, etc.)
Success Factor – Technology Advances











CMOS integration (processing power, memory size, cost reduction)
Real-time Multi-core processor architecture and mobile specific user-friendly
Operating Systems (e.g. Adroid, iOS, etc.)
RF Technology (higher frequencies, more efficient PA, etc.)
Battery technology (greater capacity, lighter)
High-resolution touch-screen displays (Gesture vs GUI, etc.)
Inexpensive digital camera technology (photo and video)
Modulation/Coding/Signal Processing/MIMO
Access Techniques (TDMA, CDMA, OFDM/SC-FDMA)
Cloud computing/Big Data
Software Defined Networking (SDN) and Network Function Virtualization (NFV)
Creative design to put all together
Success Factor – Overall Environment



Frequency allocations/Auctions
Deregulation
Government mandates


Industry consolidation


Connected cars, etc.
Google, Microsoft, Apple, Amazon, Intel were successful in
other businesses
Geopolitical-shift towards China and Asian Pacific

Market size, Manufacturing power and Intellectual capabilities
Case for 5G




Higher data transfer rate and lower latency to support new
applications (e.g. connected cars, remote sensing and
control, health monitors, etc.)
Bandwidth allocated for 2G, 3G, and 4G insufficient to meet
the needs
LTE frame structure still imposes too much latency for lowlatency applications
New applications will be defined by users, not service
providers, 4G network architectures are not sufficiently
flexible to adapt to those yet to foresee applications

New virtualized architecture (e.g. SDN/NFV) is needed
More Bandwidth

Smaller Cells (achievable with
existing 4G framework)


More complicated R.F. planning,
mobility management, etc.
New frequency allocations




No “beach front” properties
available
Higher frequencies (e.g. >24 GHz)
has very limited range
New Channel characteristics are not exactly compatible with the
signal processing techniques for 2/3/4G
New R.F. technology incompatible with existing 2/3/4G allocation
(reason for 5G)
4G Must Be a Part of 5G

Small islands of 5G at higher frequency cannot be a
network,(not much different from WiFi)




WiFi serves us well in homes, offices, and public buildings;
what has been lacking is a seamless integration with the
cellular networks in terms of access and billing
“Smart” use of “unlicensed band” asset such as WiFi is
still necessary even with new 5G band
The >24GHz band has many existing usages, allocation
may require sharing on a non-interfering basis with other
uses
Expect to see 5G to include 4G and WiFi
Latency Reduction for Critical Applications

Most of known “Latency Critical” applications has their own specialized air
interface and standards, their own needs and evolution paths




Backhaul and core networks must be part of the solution
A universal, all-inclusive framework, to address all possible needs unlikely


Desirable to internetwork with those specialized networks as needed
To the extent without compromising efficiency, latency reduction and better
QoS is desirable


Connected Vehicles (DSRC/IEEE802.11.p)
Medical and Internet of Things (WiFi, Bluetooth, Zigbee/IEEE802.15.4, NFC)
Optional sub-frame structure, reducing latency may be acceptable, but be aware of
“tail wagering the dog” effect
Creativity and entrepreneurship are best served with minimum constraints
for each application (diversity is good)
Key 5G Challenges

mmW RF technology for short range communications




Optimize air-interface design for performance in wideband mmW
channels



Beamforming at >24 GHz and 60 GHz key
Packaging existing R.F. with mmW technology in a single handset
Focus on short range, low latency applications
Acquisition and tracking of mmW signals in mobile environment
Use of alternative frequencies in case of blockages
Spectrum sharing and coexistence in the <3.5 GHz frequencies



Interference detection and cancellation
Signaling, networking and mobility management when sharing spectrum with
others
Cognitive Radio
Key 5G Challenges


Self-organized networks adapting to traffic needs and R.F.
environment
Efficient broadcast channel in a multi-band, multi-mode, mobile setting


Backhaul solutions for ultra dense cells


Acquisition and mobility management seem challenging
Copper, mmW, or free space optical links
Radio Access Network and Core Network Architecture Evolution


Hierarchical vs Centralized vs Distributed (complexity, latency and performance)
Trend seemed to push functions to “Cloud” and “Virtualization”, but what does
that mean?


Wireless service provider may no longer own a dedicated network
“Data Center” oriented network providers may play bigger roles in the equipment market
Exponential Growth will Slowdown

Underlining technology reaches maturity





Only that much content an average person can consume



Cost of new CMOS Fab limits where Moore’s law can go
Modulation/Coding/Access technology close to Shannon limit
Quality of traditional applications (voice, video) are good enough
Wireless depends on backhaul, there is always a “cord”
most of the video sessions are abandoned after a few minutes
New growth has to come from new applications
Cyber crimes/threats are dark cloud above increasingly
connected world

New applications more vulnerable, no defense is impenetrable
Conclusions




The new element of 5G will be a separate air-interface for
>24 GHz frequency that operates under the 4G umbellar
The 1000x data throughput goal will be very difficult to
realize, but may not be necessary either
5G cannot be an all inclusive air-interface standard, it needs
to co-exist with all application specific standards, such as
WiFi, Zigbee, DSRC, Bluetooth, etc.
Never less, there are many difficult technical challenges,
many opportunities for innovative ideas and new products

Download Report