UK Spectrum Policy Forum Cluster 2 Meeting – 24 July 2014 Prof Stephen Temple Visiting Professor 5G IC 5G Spectrum – the essential dialogue More information at: http://www.techuk.org/about/uk-spectrum-policy-forum All rights reserved

1. Anatomy of global mobile technology revolutions – The Essential Dialogue
Prof Stephen Temple CBE
Visiting Professor 5G IC
RESEARCH
SPECTRUM
PLANNING
STANDARDS
MAKING
5G
1. What is 5G in network terms?
2. Where is the spectrum for it?
3. What will be different about 5G
4. What are the most likely
Market
A proactive EU & global
dialogue between
research, spectrum
planning and standards
making is essential
To get this dialogue going the first “Working Assumptions” about 5G need to be
emerging now…so 4 working assumptions are tabled that address the above 4 questions
Early Spectrum Issues:
regulatory issues to resolve?
affecting spectrum choice/use?

2. 5G
“DAN enabled” so “Always sufficient” Quality of Service matches demand
Fibre Highway Lattice
SATELLITE
MASSIVE DATA ENGINES powering the Digital Economy & Social Space
5G IC
SUPER-EFFICIENT “UNIVERSAL” MOBILE DATA ACCESS
5 –10 Mb/s 700 MHz – 1900 MHz
SUPER-FAST“MOBILE”
High-density urban small-cell clusters
500 –1000 Mb/s
2 - 4 GHz
FIBRE
WIRELESS
5 –10 Gb/s
20-60 GHz
Ultra LP
I o T
CELLULAR
Surrey University
Working Assumption 1: – The
5G Network-Spectrum Vision

3. New spectrum above 20 GHz for “Wireless-fibre” at WARC-15 ought to be possible to find but there
is unlikely to be “clean” spectrum between 2-4 GHz (the range necessary for wider RF channels but still affordable cost
of area coverage) reserved for 5G “super-fast mobile”…so is spectrum sharing the answer?
 Ofcom data suggests it likely that over ~ 90% of the UK land mass some or all of
any newly released spectrum above 2GHz will lay unused for a long time.
Spectrum Range Area of UK where some of the
spectrum is unused (1)
Area of UK where all of the
spectrum is unused (1)
GSM spectrum at 900MHz or
1.8 GHz
34% 6%
3G spectrum at 2.1 GHz 87% 24%
5G at >2 & <4 GHz >>87% >>24%
 Just covering urban Britain with 200m diameter small cells would require just
under half a million such small cells…it is highly improbably that all four mobile
operators will each roll-out this density of cells…least of all by 2020
Spectrum sharing with non-5G use looks feasible particularly above 2GHz
Note 1: Ofcom UK communications infrastructure report 2011 figure 12. Numbers have been rounded. 3G figures today are likely to be lower with
improved 3G coverage but the point remains that the 2.1 GHz numbers above were for 10 years after the spectrum release in 2000.
Where is the spectrum for 5G? - Working Assumption 2: 5G “super-fast
mobile” will need to share spectrum with non-5G use in bands between 2 to
4 GHz

4. Working Assumption 3 – 5G super-fast mobile networks will be different as
they will require considerably wider RF channels widths (100-200 MHz)
There may be regulatory barriers to wide RF channels…regulators in the past have slice-
up bands for competition reasons – “the 5G Competition v Channel-width conundrum”
50 100 150 200
1000 Mb/s
500 Mb/s
86
200
433
866
(based on IEEE 802.11ac
with 256-QAM)
185MHz
90MHz
Super-fastmobilepeakdatarate
Technology
progress
eg LTE-A

5. What is the solution to “the 5G Competition v Channel-width conundrum”? Working
Assumption 4: …pooling fragments of local unused spectrum…to be discussed….
Indoor cell
Powered-down
cell
Exclusive
spectrum cell
Hierarchy key:
Expanded
spectrum cell
100
Mb/s
200
Mb/s
1
Gb/s
0
Mb/s
400
Mb/s
225
Mb/s
300
Mb/s
225
Mb/s
600
Mb/s
800
Mb/s
Exclusive
Spectrum
Allocations
Illustrative
Divided in ratio of exclusive
spectrum held when more than
one cell is co-located and active
Could also be used for low
cost high capacity backhaul in
rural areas
Cells could be powered down
for energy saving when not in
use
Indoor cell “extra
bandwidth” enabled only
by any MNO having core
spectrum (to manage
interference)
200
Mb/s
Dynamic
Spectrum
expansion
100% of allocated
bandwidth at unique
locations.
It pools unused exclusive
spectrum that would otherwise
perish - giving back contributors to
the pool far more than they put in
1
Gb/s
(Note: Assumes TDD with 1 Gb/s total peak data capacity)
A
A B
B
C
C
D
D C
Surrey University
5G IC
Dynamic
Spectrum
expansion
Dynamic
Spectrum
expansion
Dynamic
Spectrum
expansion

6. “The Essential Dialogue” - Summary of Questions/Working Assumptions
What is 5G (in network terms)?
Working Assumption: Slide 2 illustrates the emerging elements under debate
Where is the spectrum for 5G?
Working Assumption : that spectrum is unlikely to be reserved for 5G and particularly under 4
GHz.
Therefore 5G requirements for spectrum under 4 GHz may need to envisage advanced spectrum
sharing with what may exist and this looks feasible above 2 GHz
What will be different about 5G affecting spectrum choice/use?
Working Assumption: RF Channel widths will need to be much wider ie 100-200 MHz wide
What are the most likely regulatory issues to resolve? Regulators in the past
have slice-up bands for competition reasons creating a potential “5G Competition v
Channel-width conundrum”
Working Assumption: fragments of locally unused spectrum could be pooled and those
contributing to the pool are able to use these fragments to expand channels widths to offer much
higher data speeds at those locations.

7. Annex - “Working Assumptions” are a vital tool in developing a next
generation mobile technology on an open global basis
It allow complex technology specification to
progress in the absence of all the facts
A Working Assumptions is a straw-man that
allows a structured dialogue to begin across silos
Assumptions can be changed at any time all the
way through until the freezing of the standard
But changes have to be offer significant
improvements (or correct errors)
What is a Working Assumption ?
“Slow drying cement” is a good analogy for the Working Assumption…totally liquid at
the outset, can be easily re-shaped but slowing drying to provide a final solid basis