December 2014
doc.: IEEE 802.19-14/0091r0
Fair Spectrum Sharing
Date: 2014-12-19
Authors:
Name
Company Address
Alireza Babaei CableLabs
Ivan Reede
AmeriSys
858 Coal Creek Cir
Louisville, CO 80027
USA
20 Meoc, Kirkland, Qc
Canada H9H 2B3
Phone
email
+1-3036613405
[email protected]
+1-514-620-8522
[email protected]
Notice: This document has been prepared to assist IEEE 802.19. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in
this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Submission
Slide 1
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Abstract
• This document intends to start the discussion on
defining a criterion for fairness across users or systems
that horizontally coexist in a shared spectrum (e.g., in
unlicensed bands).
Submission
Slide 2
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Background
• An interest group on “Fair Spectrum Sharing” was
created in 802.19 working group during the November
2014 plenary meeting.
• The purpose of IG is “to develop an IEEE 802.19
approved document defining and specifying how to
measure fair spectrum sharing between networks,
designed to different standards, operating in unlicensed
spectrum”
Submission
Slide 3
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Scope of Fair Spectrum Sharing Document
• The “fair spectrum sharing” document should define a criterion that
takes as input a given instance of spectrum usage pattern of the
systems or users in the shared spectrum and delivers as output a
measure of fairness for this instance of spectrum sharing.
f
B
Fairness
Criterio
n
spectrum usage pattern
in frequency and time
How fair?
X% fair
t
Submission
Slide 4
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Fairness across systems or users?
• Two approaches can be followed when defining the fairness criterion:
• First: Users of the shared spectrum, irrespective of what access
technology (AT) they use, and interfering with each other must have fair
access to the wireless resources.
• Second: Systems operating in the shared spectrum and interfering with
each other must have fair access to the wireless resources.
Submission
Slide 5
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Impact of Protocols on Fairness
• Spectrum usage is highly impacted by the access protocol used by each
system or user (e.g., TDMA, CSMA/CA, OFDMA, etc.).
– The fairness criterion should be independent of the protocol details (PHY layer or access
protocol) in each system.
– The scope of fairness criterion should consider the product of
1. Bandwidth occupancy (total including the guard bands) divided by the total spectrum in
the band/channel
2. Total occupancy duty cycle
Example:
System “A” occupies 40% of the band 20% of the time- i.e., a 0.08 occupancy
System “B” occupies 1% of the band 100% of the time- i.e., a 0.01 occupancy
System “C” occupies 100% of the band 100% of the time- i.e., a 1.00 occupancy
• Protocols or spectrum sharing rules to enable fairness across systems or
users of the shared spectrum are outside the scope of this document.
Submission
Slide 6
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Fairness requirements
• For fairness across systems:
– When observing n systems sharing the spectrum for a long enough period of time, each
system, provided that its resource demand is larger than or equal to the equal share of
resources (total wireless resources divided by n), must have used equal amount of wireless
resources.
• If any of the systems’ demand is less than an equal share of resources, it should receive as much
wireless resource as it demands.
• If a system does not need a resource at a given moment, it must relinquish the resource so other
systems that may need it may share it.
• For fairness across users:
– When observing M users of the shared spectrum (irrespective of what AT they are using) for
a long enough period of time, each user, provided that its resource demand is larger than or
equal to the equal share of resources (total wireless resources divided by M) must have used
equal amount of wireless resources.
• If any of the users’ demand is less than an equal share of resources, it should receive as much
wireless resource as its demands.
• If a user does not need a resource at a given moment, it must relinquish the resource so other users
that may need it may share it.
Submission
Slide 7
Alireza Babaei, CableLabs
December 2014
doc.: IEEE 802.19-14/0091r0
Conclusions
• The fairness criterion should be defined for fairness across
users of the spectrum (irrespective of their AT) and/or across
systems operating in the spectrum.
• The fairness criterion should look at the spectrum usage
pattern of systems or users (ratio of occupied spectrum over
total available spectrum times the duty cycle of spectrum
occupancy) for a long enough period of time.
• Protocols or spectrum sharing rules to enable fairness across
systems or users of the shared spectrum are outside the scope
of this document.
Submission
Slide 8
Alireza Babaei, CableLabs