January 2007

Mark Austin and Peter Spital, Ofcom

Slide 1

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT – A Tool for Coordination Between Technologies

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.

Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.19.

Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the TAG of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <shellhammer@ieee.org> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.19 TAG. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>.

Date: 15-01-2006

Name Company Address Phone email Mark Austin Ofcom 2a Riverside House,

Southwark Bridge Road, London, SE1 9HA , UK

+4420 7783 4364

mark.austin@ofcom.org.uk

Peter Spital Ofcom 2a Riverside House, Southwark Bridge Road, London, SE1 9HA , UK

+4420 77830 4369

Peter.Spital@ofcom.org.uk

Authors:

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 2

doc.: IEEE 802.19-07/0003r0

Submission

Spectrum Engineering Advanced Monte- Carlo Analysis Tool

A Tool for

Coordination Between Technologies

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 3

doc.: IEEE 802.19-07/0003r0

Submission

Sharing methods:

• Spacing radio systems in frequency– Guard bands

• Spacing geographically– Using the gaps between intended deployment areas

• Power and Location– Using appropriate technology in appropriate locations

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 4

doc.: IEEE 802.19-07/0003r0

Submission

Defining the sharing rules:

• Analytical analysis, usually by worst-case approach:– Minimum Coupling Loss (MCL) method, to establish rigid rules

for minimum “separation”

• Statistical analysis of random trials:– The Monte-Carlo method, to establish probability of interference

for a given realistic deployment scenario

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 5

doc.: IEEE 802.19-07/0003r0

Submission

MCL principle:

• The stationary worst-case is assumed

Wanted Signal

Victim

Interferer

Dmin, or minimum frequency separation for D=0

– However such worst-case assumption will not be permanent during normal operation and therefore, for mobile technologies, sharing rules tend to be unnecessarily stringent

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 6

doc.: IEEE 802.19-07/0003r0

Submission

Monte-Carlo principle:

• Repeated random generation of interferers and their parameters (activity, power, etc…)

– After many trials not only unfavourable, but also favourable cases will be included. Reveals the service experienced by the user.

Wanted Signal

InactiveInterferer

Victim

ActiveInterferer

t=t0

t=t1t=ti

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 7

doc.: IEEE 802.19-07/0003r0

Submission

Monte-Carlo assumptions:

• User will need to define the distributions of various input parameters, e.g.:– How the power of interferer varies (PControl?)

– How the interferer’s frequency channel varies

– How the distance between interferer and victim varies, and many others

• If all of the variables in all of the trials are equally probable.– Results will inevitably reflect user experience

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 8

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT:

• Spectrum Engineering Advanced Monte-Carlo Analysis Tool

• An open, free software tool for analysing the co-existence of radio systems

• Developed by engineers for use by administrators

• Supported by CEPT

• Maintained by the ERO

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 9

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT:

• User defines a scenario, describing mutual positioning of two systems, in geographical domain…

5 km MS-Iti

Wr BS-Vr

Wti

…as well as many other parameters:

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 10

doc.: IEEE 802.19-07/0003r0

Submission

Scenario parameters:

• Positioning of two systems in frequency

• Powers

• Masks

• Activity

• Etc.

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 11

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT event generator:

• Random generation of transceivers

• Link budget

• Signal values

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 12

doc.: IEEE 802.19-07/0003r0

Submission

How event generator works:

• Succession of snapshots…

VR

WT

1) Calculate d, Ptx, GaTx, GaRx, L

2) Calculate dRSSi

dRSS

Snapshot#iRSS

Snapshot#IT

WR

1) Calculate d, Ptx, GaTx, GaRx, L

2) Calculate received signal, if PC, adjust Ptx

1) Calculate d, Ptx, GaTx, GaRx, L

2) Calculate iRSSi VR

WT

IT

WR

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 13

doc.: IEEE 802.19-07/0003r0

Submission

Result of simulations:

• Vectors for wanted and interfering signals:

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 14

doc.: IEEE 802.19-07/0003r0

Submission

Evaluating interference:

• By comparing signal instances: - For each random event:

Noise Floor (dBm)

Desired signal value (dBm)

Interfering signal (dBm) C/Itrial > C/Itarget?

Interference (dB)

- If C/Itriali >C/Itarget: “good” event

- If C/Itriali <C/Itarget: “interfered”

- Finally, after cycle of Nall events: Overall Pinterference= 1- (Ngood/Nall)

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 15

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT-3 (2005):

• CDMA:

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 16

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT-3:

• Interference into CDMA as capacity loss:

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 17

doc.: IEEE 802.19-07/0003r0

Submission

OFDM Modelling

• A new Feature for SEAMCAT• Recognises the demand for mobile OFDM modelling.

Builds on the proven capability of SEAMCAT• Supported by:

– CEPT Working Group SE– SE7, the Land Mobile Working Group– Qualcomm.

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 18

doc.: IEEE 802.19-07/0003r0

Submission

OFDMA

• The mobile variant of OFDM

• Key features:– Multiple slots per user

– Sub-slot hopping on either a single symbol or a small group of symbols

– Forward error correction over multiple symbols

– Fast adjustment of Modulation and FEC

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 19

doc.: IEEE 802.19-07/0003r0

Submission

Key Assumptions

• Interference assumed to be corrected across multiple sub-slots by the forward error correction

• Mean data rate is assumed to be dependent on the mean C/I

• Segment is short enough that the modulation and forward error correction can rapidly respond to changing C/I.

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 20

doc.: IEEE 802.19-07/0003r0

Submission

Basis of Methodology

• For each snapshot:– The users will be randomly distributed

– The users will be assigned to a base station

– The C/I ratio for each terminal will be calculated

– The required modulation and error correction will be looked up

• When the system is stable interference is applied– The effect on the C/I ratio will be calculated

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 21

doc.: IEEE 802.19-07/0003r0

Submission

Measuring the Results

• The output of the model will include:– Number of terminals unable to connect because of cell overload

– Number of terminals unable to achieve required C/I before interference

– Number of additional terminals rejected after interference

– Data rate before and after interference

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 22

doc.: IEEE 802.19-07/0003r0

Submission

Testing the Concept

• Bespoke software have been used for Flash OFDM and WiMAX– Flash OFDM performance similar to real network

• Models revealed that customer outage is a more sensitive indicator of performance than data rate

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 23

doc.: IEEE 802.19-07/0003r0

Submission

New Variants of OFDM

• Certain that use of OFDM will increase

• TDD variants can use ‘old’ SEAMCAT

• Technology specific plug-ins planned to permit easy adoption of future OFDMA implementations.– New plug-ins would be obtained by modifying existing plug-ins

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 24

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT

• Proven

• Maintained

• Supported by the ERO

• Flexible

• Optimised for Land Mobile use

• An Open Technology on an Open Software platform

January 2007

Mark Austin and Peter Spital, Ofcom

Slide 25

doc.: IEEE 802.19-07/0003r0

Submission

SEAMCAT

• A Solution for the Future

• Collect it from:– http://www.seamcat.org/

• Thank You