module d3 - École polytechnique fédérale de lausannemobnet.epfl.ch/slides/d3-moreoncellnw.pdf ·...
TRANSCRIPT
![Page 1: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/1.jpg)
Module D3
• More on Cellular Networks– Femtocells– Frequency Management– Mobility Management
• Wireless Ad Hoc Networking– Routing
• Examples
mobnet.epfl.ch
![Page 2: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/2.jpg)
Femtocells
2
• Home base stations for mobile networks– Licensed spectrum– Low‐power, low‐range– At user’s premises– Operated by cell. provider– Cellular access throughfixed broadband connection (ADSL,…)
• Why femtocells?– Better throughput, coverage, lower prices for users– Unload wide area cellular networks, reduce op. costs
![Page 3: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/3.jpg)
Femtocell Deployment
3
![Page 4: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/4.jpg)
Network ArchitecturesUMTS LTE
4
![Page 5: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/5.jpg)
Security and Privacy Challenges• New threats
– Attacks on femtocells– Attacks on backhaul and core network (IPsectunnel)
Source: www.SafeNet-Inc.com
5
FGW:FemtocellGateway
![Page 6: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/6.jpg)
Femtocells : Radio Measurements
Measurements carried out byCarl Hedari and Charles‐Edmond Renouardwith the contribution from Igor Bilogrevic
6
![Page 7: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/7.jpg)
• Radiation pattern shows the performance of the antenna– The signal does not propagate equally all around the femtocell
– W‐CDMA Femtocell, ~5 MHz channel bandwidth
Femtocells – Radio Measurements
7
![Page 8: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/8.jpg)
How to Test a Femtocell in a Femtocell‐less Country
• The femtocell should only work in its originating country, mainly because of frequency allocation issues
• Often, the femtocell uses only the IP verification and customer address to be localized
• Idea: fool the verification process using a VPN located in country X
8
![Page 9: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/9.jpg)
AnechoicChamber at EPFL
Designed to stop reflections of RF
• Simulates a quiet space of infinite dimension
• Removes all source of exterior RF
Avoids jamming Swiss carriers and allows isolating the femtocell
9
![Page 10: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/10.jpg)
Spectrum Analyzer – One Femtocell
Femtocell :
• Frequency : 2.137 GHz (UMTS)
• Power : ‐60.25 dBm
• Channel : 2.1351 GHz to 2.1396 GHz
10
Spectrum Analyzer
![Page 11: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/11.jpg)
Spectrum Analyzer – Two Femtocells
• Another femtocell brought into the anechoic chamber
The femtocell listens to stations emitting on the same frequency and adapts its power output.
11
![Page 12: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/12.jpg)
Spectrum Analyzer – Two Femtocells
12
One femtocell operating normallyPower : ‐60.25 dBm
The same femtocell and another femtocell nearby. Power : ‐54.18 dBm
With two active femtocells, the received power was increased by 6 dB (4 times more power)
![Page 13: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/13.jpg)
Radio Traces : Measures
• 1 Femtocell• 1 Mobile from Operator X• 1 Mobile from Orange CH
• An antenna was plugged into a 6 GHz capable Oscilloscope, and put inside the chamber to “listen”
• The radio traces are displayed on the screen
13
Inside the anechoic chamber
![Page 14: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/14.jpg)
Experiment 1 : Call established from Orange CH to X
50cm 50cm ∞
Oscilloscope(not spectrumanalyzeranymore)
Fs = 5 GHz
FemtocellMobile X Orange CH
14
Femtocell & Mobile X
![Page 15: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/15.jpg)
Experiment 2 : Call established between two Orange mobiles
2m 2.5m
Oscilloscope Orange CH Orange CH
Fs = 2.5 MHz
Note: The sampling theorem was not respected for practical issues 15
![Page 16: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/16.jpg)
Experiment 3 : Initialization of the femto‐cell
50cm 50cm ∞
Oscilloscope FemtocellMobile X Orange CH
Note: The sampling theorem was not respected for practical issues
Fs = 2.5 MHz
16
![Page 17: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/17.jpg)
Frequency Management
![Page 18: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/18.jpg)
18
Frequency Management• In all countries of the world, the licensed spectrum ismanaged by the government and (usually) leased to private operators
• Regulation authority– In Switzerland: Federal Commission for Communications, or ComCom; assisted by BAKOM
– In the US: FCC– In the EU: each country still has its national regulationauthority
• Some political willingness (especially in the US) to reduce the role of the FCC Dynamic Spectrum Allocation (cognitive radios)See the IEEE DySpan conference (ieee‐dyspan.org)
![Page 19: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/19.jpg)
19
Procedure for Frequency Allocation
• 2 main options– Auction– Beauty contest
• Usually fixed price• Based on very detailed dossiers+ : price pre‐determined‐ : temptation/suspicion of bribery; no price discovery
![Page 20: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/20.jpg)
20
Auctioning of Frequencies• Goal of auction: best possible allocation of frequencies to operators
• Auctions are notmeant to maximize the revenue for the government
• Splitting of the frequency bands in blocks (e.g., of 2*5Mhz)
• Issue: how to combine the auctioned blocks• Caps in high‐value bands to avoid unfair behavior• Typical duration of allocation: 10 to 20 years• Minimal (or starting) price: xxx CHFrs/MHz*Year (definedby law in the case of CH)
![Page 21: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/21.jpg)
21
The case of Switzerland• 3 main cellular operators (cellcos)
– Swisscom (state‐controlled) has 60% of the mobile market– Failed attempt of merger of Orange and Sunrise (in 2010)
• Good quality of service, but high prices• Swiss pecularities: topography, super‐tight emissionregulations, site acquisitions (to set up base stations) often problematic, expensive manpower, high‐revenue and change‐averse population
• All licencies (800, 900, 1800, 2100 and 2600MHz) to be(re‐)allocated as of 2013 or 2016 until 2028 (auctionrun in February 2012; generated 996 MCHFrs)
![Page 22: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/22.jpg)
![Page 23: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/23.jpg)
non-ionizing radiation
![Page 24: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/24.jpg)
Previous frequency allocation in CH
• GSM 900 Frequencies• Allocation until 31.12.2013• No free frequencies
• GSM 1800 Frequencies• Allocation until 31.12.2013• Some frequencies available (ex. Tele2)
• UMTS Core Band• Allocation until 31.12.2016• Some frequencies available
68MHz
Low frequencies
High frequencies
GSM900
Sunrise (50%)
Swisscom (40%)Orange (10%)
Orange (40%)
Sunrise (19%)
Swisscom (21%)
In&Phone (8%)ex. Tele2 (12%)
Sunrise (25%)
Orange (25%)
Not allocated (25%)
Swisscom (25%)
GSM1800
UMTS core band (2100 MHz)
146MHz
140MHz
Courtesy: BAKOM
Location of base stations:http://map.funksender.admin.ch/webgis/bakom.php
Frequency allocation plan:www.bakom.admin.ch/themen/frequenzen/00652/00654/index.html?lang=en
![Page 25: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/25.jpg)
Previous frequency allocation in CHGSM 900
Company Bands Expiration
Swisscom 2 x 13.6 MHz 31.12.2013
Sunrise 2 x 17 MHz 31.12.2013
Orange 2 x 3.2 MHz 31.12.2013
GSM 1800
Company Bands Expiration
Swisscom 2 x 15.2 MHz 31.12.2013
Sunrise 2 x 13.6 MHz 31.12.2013
Orange 2 x 29.4 MHz 31.12.2013
Ex.Tele2 2 x 8.6 MHz free
In&Phone 2 x 5.8 MHz 31.12.2013
UMTS 2100
Company Bands Expiration
Swisscom 2 x 15 MHz FDD + 5 MHz TDD 31.12.2016
Sunrise 2 x 15 MHz FDD + 5 MHz TDD 31.12.2016
Orange 2 x 15 MHz FDD + 5 MHz TDD 31.12.2016
BWA (3.5 GHz)
Company Bands Expiration
Swisscom 2 x 21 MHz 31.12.2016
Callix (Inquam) 2 x 21 MHz 31.12.2016
![Page 26: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/26.jpg)
Why an invitation to bid? All mobile radio frequencies auctioned together • Bidders can purchase a new, future‐proof spectrum package• A world first
Expiring licences:• GSM licences (900 + 1800 MHz): End of 2013• UMTS licences (2100 MHz): End of 2016
Many new mobile radio frequencies are available:• "Digital dividend" (in the 800 MHz band) Good propagation properties (even inside houses) Switzerland one of the first countries in Europe
• UMTS extension band (2600 MHz) Suitable for LTE technology with high bandwidths
Goals: ‐ more frequencies for more bandwidth in mobile communications‐ efficient use of spectrum with new technologies (LTE)
Note: This slide and some of the following adapted from a slideshow kindly provided by Urs von Arx and Martin Dummermuth (BAKOM)
![Page 27: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/27.jpg)
Rapidly growing data traffic in mobile radioRapidly increasing amounts of data on mobile radio networks Doubling every 9‐12 months
More and more smartphones (iPhone, Android devices, etc): > 350 000 apps (incl. social networks such as Facebook and Twitter)mobile internet, mobile TV, YouTube... "Cloud computing" also mobile: same content present everywhere
Business Mobility: Office applications and content on all devices new, flexible forms of working
All internet applications and content anywhere, anytime on a mobile phone
Increase in network capacity essential
![Page 28: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/28.jpg)
New mobile radio technologies are coming
HSPA+ (Evolved High Speed Packet Access "plus")• Considerable increase in transfer rates (compared with UMTS)• Market‐ready devices are already available
LTE (Long Term Evolution of UMTS; 4G)
• 3 to 4 times higher spectrum efficiency than UMTS/HSPA• Increase in data rates to up to 100 Mbit/s in the downstream• Greater capacity in the network at a relatively low cost
New generation of mobile communicationse.g. mobile HDTV, video streaming, on‐line gaming…
![Page 29: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/29.jpg)
Why an auction?• A transparent procedure
• The market determines the value of frequencies
• The market decides on the scope of the licences (not the regulator): therefore: auction of small frequency blocks Operators can acquire a new spectrum package
which corresponds to their business models for the future
• Equal treatment of all candidates: All were able to take part on equal terms No unilateral preference for any new entrants
Network operators purchase spectrum corresponding to their needs
No new market entry of an other network operator
![Page 30: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/30.jpg)
Result of the auction: CHFrs 996'268'000
Frequency band Orange Sunrise Swisscom
800 MHz 20 MHz 20 MHz 20 MHz
900 MHz 10 MHz 30 MHz 30 MHz
1800 MHz 50 MHz 40 MHz 60 MHz
2.1 GHz FDD 40 MHz 20 MHz 60 MHz
2.1 GHz TDD 0 0 0
2.6 GHz FDD 40 MHz 50 MHz 40 MHz
2.6 GHz TDD 0 0 45 MHz
Adjudication price 154‘702‘000 481‘720‘000 359‘846‘000
![Page 31: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/31.jpg)
Goals of the frequency allocation achieved
• Consumers benefit: Technological innovation continues; new broadband services. High quality and good coverage
• Technological progress supported: free choice of technology Operators can use LTE (high‐speed broadband even in peripheral regions)
• A frequency allocation with a promising future: All network operators acquire good spectrum + more spectrum
• Long‐term planning and investment security: Network operators can plan up to 2028
• Appropriate proceeds from the auction: A scarce public resource allocated appropriately Benefits the community
![Page 32: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/32.jpg)
Reasons for the chosen form of the auction
• The participants in the auction can bid on frequency packages.
• The frequency packages correspond to their business model
• Value, for which bidders are prepared to pay
• Continuity for existing licensees:
• Consistent with the existing frequency allocation
![Page 33: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/33.jpg)
Multi‐phase sequence of the auction
• Auction in two stages. The bidders were able:
1. to combine frequency ranges optimally;
2. bid in a second phase bid for the preferred frequencies within the individual ranges.
• The auction took place over the internet from the bidders' company headquarters
![Page 34: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/34.jpg)
Example: Combinatorial Clock Auction
Clock rounds
Excessdemandin anyband?
Supplementaryround (fine tune expression of
wishes)
Assignment of frequencies
No
Yes
Increase price of band(s) with excess demand
![Page 35: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/35.jpg)
Bidding restrictions
Bidding restrictions (spectrum caps)
• Maximum extent of frequencies per frequency band
• Competition
• Enabling competition during the auction
• Increasing competition as much as possible after the auction by ensuring sufficient spectrum per bidder
• No bidder may acquire the entire 900 MHz spectrum (GSM)
• No market displacement of existing operators possible
• Existing UMTS operators can purchase at least the current range of frequencies in the 2100 MHz band (UMTS)
• No single bidder can dominate the major part of the GSM spectrum (900 MHz, 1800 MHz)
![Page 36: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/36.jpg)
Distribution of the frequency spectrum (I)
93.8
96.2
99.4
255
160
160
0 50 100 150 200 250 300
Swisscom
Sunrise
Orange
MHz
Spectrum distribution before and after the auction
purchasedat auction
to date
![Page 37: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/37.jpg)
Distribution of the frequency spectrum (II)
255
160
160
Spectrum distributionAuction result (MHz)
SwisscomSunriseOrange
![Page 38: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/38.jpg)
Allocation of the frequency spectrum
20
30
60
0
60
40
45
20
30
40
0
20
50
0
20
10
50
0
40
40
0
0 10 20 30 40 50 60 70
800MHz (paired)
900MHz (paired)
1800MHz (paired)
2100MHz (unpaired)
2100MHz (paired)
2600MHz (paired)
2600MHz (unpaired)
Spe
ctru
mdi
strib
utio
n
MHz
Auction result Spectrum allocation
OrangeSunriseSwisscom
![Page 39: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/39.jpg)
Licenses (1)• Term
• Planning/investment security: early allocation and a term extending until 2028• Utilization of free frequencies from award of license onwards
• Neutrality with respect to technology• Flexible utilization of the spectrum for future developments
• Conditions relating to utilization• Gradation:
‐ 50% population coverage for frequencies < 1 GHz‐ 25% population coverage for frequencies > 1 GHz
• No frequency hoarding• Freedom with respect to configuration (coverage, quality)• Supervisory procedures in the event of non‐compliance
![Page 40: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/40.jpg)
Licenses (2)
• Protection from immissions and spatial planning• Conditions as strict as those in existing licences• Provisions of Ordinance on Protection from Non‐Ionising Radiation (OPNIR)• Shared use of sites outside the construction zone• Informing the cantons about network planning in good time
![Page 41: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/41.jpg)
41
References on Auctions
• Cramton, Shoham and Steinberg (eds.): Combinatorial Auctions, MIT Press, 2006
• Ausubel, Lawrence M. and Paul Milgrom (2002), “Ascending Auctions with Package Bidding,” Frontiers of Theoretical Economics, 1, 1‐45, http://www.bepress.com/bejte/frontiers/vol1/iss1/art1.
![Page 42: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/42.jpg)
Mobility Management
![Page 43: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/43.jpg)
43
2. Receive the ID of the LA3. Compare with stored ID4. If different, update
and ask for registration
User Tracking: Geographic‐based Strategy
Location area 1 (ID = 1) Location area 2 (ID = 2)
• Base stations periodically broadcast the ID of the LA• Users compare their last LA ID with the current ID, and transmits a registration message whenever the ID is different
• When there is an incoming call directed to a user, all cells within its current LA are paged
1. Change LA
5. Inform the HLRof the new LA ID
![Page 44: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/44.jpg)
Location and Identity Privacy• Temporary Mobile Subscriber identifiers – TMSI –changed after crossing Location Area (LA) border or time‐out trigger
LA 0LA 1
LA 2
LA 3
Pseudo A
Pseudo B
Pseudo C
Pseudo D
44
![Page 45: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/45.jpg)
45
Handover
BS1 BS2
A B
t
Receivedsignal level
Level at B
Level at which handover is made(call transferred to BS2)
![Page 46: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/46.jpg)
46
![Page 47: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/47.jpg)
47
MTSO:MobileTelecommunicationsSwitching Office(also called MSC:Mobile Switching Center)
![Page 48: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/48.jpg)
48
Handover Strategies• The handover power level must be carefullychosen– Too small => risk of superfluous handovers– Too high => risk of losing the call due to weak signal
• Mobile Assisted Handover (MAHO) – Mobiles measure power from surrounding base stations
– Report to the serving base station– Handover if the power received from another station exceeds the serving station power by a certain threshold for a certain amount of time
![Page 49: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/49.jpg)
Hard/Soft Handover
Hard: Communicate with one cell at a timeSoft: Communicate with two cells simultaneously
TDMA & FDMA: Hard– Could technically use soft handover, but would be costly as it would require multiple parallel radio modules
CDMA: Soft – Needed to avoid near‐far problem (i.e., Detect weaker signal amongst strong signals)
49
![Page 50: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/50.jpg)
50
Roaming Principle
Roaming agreement
Subscriberdatabase(IDs,keys,bills,…)
Home network
Subscriberdatabase(IDs,keys,bills,…)
Visited network
User
![Page 51: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/51.jpg)
51
Roaming Architecture
Servicelogic
HomeLocationRegister
BaseStation
Servicelogic
VisitingLocationRegister
BaseStation
PSTN + Data Network
HomeNetwork
VisitedNetwork
![Page 52: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/52.jpg)
![Page 53: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/53.jpg)
53
Mobile Ad Hoc Networks
![Page 54: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/54.jpg)
54
The classic solution for mobile networks
• 2nd generation (GSM, IS‐41), 3rd generation (UMTS), 4th generation (LTE)• Huge, expensive fixed infrastructure• License for a share of the spectrum• Operational responsibility: network operators (telcos, ISPs)
![Page 55: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/55.jpg)
55
The new paradigm: ad hoc networks
• Terminal and node merge• Everything is potentially mobile• Initial applications: communication in the battlefield (Packet Radio
Networks, in the 70’s)• The network is self‐organized when it is run by the users themselves• Similar trend at the application layer: peer‐to‐peer
(e.g., Napster Gnutella, BitTorrent)
![Page 56: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/56.jpg)
56
Application examples of ad hoc networks
• Sensor networks• Hybrid cellular / ad hoc networks (multi‐hop cellular
networks)• Cars
– Collision avoidance– Optimization of traffic flows– …
• Crisis networks (e.g., rescue operations after major disaster)
• Military networks
• Similar concept: Delay Tolerant Networks (DTNs)
![Page 57: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/57.jpg)
57/58
Sensor networks
• Large number of sensor nodes, a few base stations
• Sensors are usually battery powered:– Main design criteria: reduce the energy consumption
• Multi‐hop communication reduces energy consumption:– Overall energy consumption can be reduced, if packets are sent in several smaller hops instead of one long hop
– Fewer re‐transmissions are needed due to collisions
![Page 58: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/58.jpg)
58/58
Wireless Mesh NetworksWired Access Point (WAP)
(a) A WiFi Network
• Wireless Mesh Network (WMN): Same coverage as with WiFi networks but with only one WAP (and several TAPs).
• WMNs allow a fast, easy and inexpensive network deployment.
• However, the lack of security guarantees slows down the deployment of WMNs
![Page 59: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/59.jpg)
59
What is a VANET(Vehicular Ad hoc NETwork)?
Roadside base station
Inter-vehicle communications
Vehicle-to-roadside communications
Emergency event
• Communication: typically over the Dedicated Short Range Communications (DSRC) (5.9 GHz)• Example of protocol: IEEE 802.11p• Penetration will be progressive (over 2 decades or so)
![Page 60: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/60.jpg)
60
A smart vehicle
Forward radar
Computing platform
Event data recorder (EDR)Positioning system
Rear radar
Communication facility
Display
(GPS)
Human-Machine Interface
![Page 61: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/61.jpg)
61
Vehicular communications: why?
• Combat the awful side‐effects of road traffic– In the EU, around 40’000 people die yearly on the roads; more
than 1.5 millions are injured– Traffic jams generate a tremendous waste of time and of fuel
• Most of these problems can be solved by providing appropriate information to the driver or to the vehicle
• More information: ACM VANET Workshop; ivc.epfl.ch
![Page 62: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/62.jpg)
62
Upper bound for the throughput of ad hoc networksIf we have:
- identical randomly located nodes- each capable of transmitting bits/sThen the throughput ( ) obtainable by each node for a destination is
( )log
nW
nrandomly chosen
Wnn n
Ref: P. Gupta, P. Kumar, The Capacity of Wireless NetworksIEEE Transactions on Information Theory, March 2000
![Page 63: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/63.jpg)
63
Intuition behind the upper bound
N nodes (users)
O(N) users O(N) users
Cut set ~ N
O(N) transmissions from left to right
over
O( ) transmission links
mean
O( ) capacity per attempted transmission
N
1N
Ways to improve scalability:• Directional antennas• Locality of the traffic• Hybrid system
![Page 64: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/64.jpg)
64
Routing in ad hoc networks• Peculiarities
– Node mobility– High rate of link failure Traditional routing approaches are not well suited
• Assumptions– Multihop communication– Symmetric links (in most cases)– Omnidirectional antennas (in most cases)– All nodes have equal capabilities and responsibilities
• Figures of merit– Latency of route discovery– Overhead (bandwidth, energy, processing power)– Security
• Current status of research: – Many, many proposals– Optimal solution depends on deployment scenario: mobility patterns,
radio model, traffic characteristics,…
![Page 65: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/65.jpg)
65
Brief reminder : Link‐state protocols
• Example: OSPF• May consume a lot of resources to update the routes
• Techniques to alleviate the problem : limit the propagation of information
• Does not seem to be well suited to cope with mobility
![Page 66: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/66.jpg)
66
Distance vector routing (1/2)
0 1 5 ¥
1 0 1 3
5 1 0 7
¥ 3 7 0
A
B
D
C
13
1
5 7
A
B
C
D
A B C D
1 0 1 3
Distancevector
Distancevector of B
2 1 2 4
+ Distance from A to B =
Cost to dest.via B
nTake the min
0 1 2,B 4,B
(1 row stored in each node)
![Page 67: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/67.jpg)
67
Distance vector routing (2/2)
• Even if the updates are asynchronous, the routing tables converge
• The algorithm is often called Bellman‐Ford• Problem: undesirable behaviour when links go up and down (e.g., count to infinity problem)
![Page 68: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/68.jpg)
68
Routing protocols for wireless ad hoc networks
Response time,bandwidth Energy
Mobile ad hoc networks Sensor networks
Proactiveprotocols
Reactiveprotocols
Destination-SequencedDistance-Vector (DSDV)
Optimized Link-State Routing(OLSR)
Ad Hoc On-DemandDistance-Vector(AODV)
DynamicSourceRouting(DSR)
Geography-based routing
Cluster-based(or hierarchical)routing
Geodesic packetforwarding
![Page 69: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/69.jpg)
69
Dynamic source routing (DSR)
• Reactive routing protocol• 2 phases, operating both on demand:
– Route discovery• Used only when source S attempts to to send a packet to destination D• Based on flooding of Route Requests (RREQ)
– Route maintenance• makes S able to detect, while using a source route to D, if it can no longer use its route (because a link along that route no longer works)
![Page 70: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/70.jpg)
70
DSR: Route discovery (1)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
![Page 71: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/71.jpg)
71
DSR: Route discovery (2)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
(S)
![Page 72: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/72.jpg)
72
DSR: Route discovery (3)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
(S,A)
(S,E)
![Page 73: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/73.jpg)
73
DSR: Route discovery (4)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
(S,E,G)
(S,B,C)
![Page 74: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/74.jpg)
74
DSR: Route discovery (5)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
(S,E,G,J)
(S,A,F,H)
![Page 75: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/75.jpg)
75
DSR: Route discovery (6)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q (S,A,F,H,K)
![Page 76: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/76.jpg)
76
DSR: Route discovery (7)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
(S,A,F,H,K,P)
![Page 77: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/77.jpg)
77
DSR: Route discovery (8)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
RREP(S,E,G,J,D)
![Page 78: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/78.jpg)
78
DSR: Route Discovery (9)
• Route reply by reversing the route (as illustrated) works only if all the links along the route are bidirectional
• If unidirectional links are allowed, then RREP may need a route discovery from D to S
• Note: IEEE 802.11 assumes that links are bidirectional
![Page 79: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/79.jpg)
79
DSR: Data delivery
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
DATA(S,E,G,J,D)
![Page 80: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/80.jpg)
80
DSR: Route maintenance (1)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
DATA(S,E,G,J,D)
X
![Page 81: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/81.jpg)
81
DSR: Route maintenance (2)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
XRERR(G-J)
When receiving the Route Error message (RERR), S removes the broken link from its cache.It then tries another route stored in its cache; if none,it initializes a new route discovery
![Page 82: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/82.jpg)
82
DSR: Optimization of route discovery: route caching
• Principle: each node caches a new route it learns by any means
• Examples– When node S finds route (S, E, G, J, D) to D, it also learns route (S, E, G) to node G
– In the same way, node E learns the route to D– Same phenomenon when transmitting route replies
• Moreover, routes can be overheard by nodes in the neighbourhood
• However, route caching has its downside: stale caches can severely hamper the performance of the network
![Page 83: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/83.jpg)
83
DSR: Strengths
• Routes are set up and maintained only between nodes who need to communicate
• Route caching can further reduce the effort of route discovery
• A single route discovery may provide several routes to the destination
![Page 84: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/84.jpg)
84
DSR: Weaknesses• Route requests tend to flood the network and generally reach all the nodes of the network
• Because of source routing, the packet header size grows with the route lengh
• Risk of many collisions between route requests by neighboring nodes need for random delays before forwarding RREQ
• Similar problem for the RREP (Route Reply stormproblem), in case links are not bidirectional
Note: Location‐aided routingmay help reducing the number of useless control messages
![Page 85: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/85.jpg)
85
Ad Hoc On‐Demand Distance Vector Routing (AODV)
• As it is based on source routing, DSR includes source routes in data packet headers
• Large packet headers in DSR risk of poor performance if the number of hops is high
• AODV uses a route discovery mechanism similar to DSR, but it maintains routing tables at the nodes
• AODV ages the routes and maintains a hop count • AODV assumes that all links are bi‐directional
![Page 86: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/86.jpg)
86
AODV : Route discovery (1)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
![Page 87: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/87.jpg)
87
AODV : Route discovery (2)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
Note: if one of the intermediate nodes (e.g., A)knows a route to D, it responds immediately to S
: Route Request (RREQ)
![Page 88: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/88.jpg)
88
AODV : Route discovery (3)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
: represents a link on the reverse path
![Page 89: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/89.jpg)
89
AODV : Route discovery (4)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
![Page 90: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/90.jpg)
90
AODV : Route discovery (5)
E G
M
H
R
FA
B
C
I
DS
K
N
L
PJ
Q
![Page 91: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/91.jpg)
91
AODV : Route discovery (6)
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
![Page 92: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/92.jpg)
92
AODV : Route discovery (7)
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
![Page 93: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/93.jpg)
93
AODV : Route reply and setup of the forward path
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
: Link over which the RREP is transmitted: Forward path
![Page 94: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/94.jpg)
94
Route reply in AODV
• In case it knows a path more recent than the one previously known to sender S, an intermediate nodemay also send a route reply (RREP)
• The freshness of a path is assessed by means of destination sequence numbers
• Both reverse and forward paths are purged at the expiration of appropriately chosen timeout intervals
![Page 95: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/95.jpg)
95
AODV : Data delivery
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
Data
The route is not included in the packet header
![Page 96: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/96.jpg)
96
AODV : Route maintenance (1)
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
Data
X
![Page 97: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/97.jpg)
97
AODV : Route maintenance (2)
M
D
K
L
PJ
E G
H
R
FA
B
C
I
S
N
Q
XRERR(G-J)
When receiving the Route Error message (RERR), S removes the broken link from its cache.It then initializes a new route discovery.
![Page 98: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/98.jpg)
98
AODV: Destination sequence numbers
• If the destination responds to RREP, it places its current sequence number in the packet
• If an intermediate node responds, it places its record of the destination’s sequence number in the packet
• Purpose of sequence numbers:– Avoid using stale information about routes– Avoid loops (no source routing!)
![Page 99: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/99.jpg)
99
AODV : Avoiding the usage of stale routing tables
S DA
B
DSN(D) = 5
: Forward path
S
D
A
B
DSN(D) = 5
… …
DSN(D) = 8
1. 2.
S
D
A
B
DSN(D) = 5
…
DSN(D) = 8
3.
RREQS
D
A
B
DSN(D) = 5
…
DSN(D) = 8
RREP
4.
![Page 100: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/100.jpg)
100
AODV : Avoiding loops
A B S D
C
: Forward path
• Assume there is a route between A and D; link S-D breaks; assume A is not aware of this, e.g. becauseRERR sent by S is lost
• Assume now S wants to send to D. It performs a RREQ, which can be received by A via path S-C-A• Node A will reply since it knows a route to D via node B• This would result in a loop (S-C-A-B-S)• The presence of sequence numbers will let S discover that the routing information from A is outdated• Principle: when S discovers that link S-D is broken, it increments its local value of DSN(D). In this way,
the new local value will be greater than the one stored by A.
X
![Page 101: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/101.jpg)
101
AODV (unicast) : Conclusion
• Nodes maintain routing information only for routes that are in active use
• Unused routes expire even when the topology does not change
• Each node maintains at most one next‐hop per destination
• Many comparisons with DSR (via simulation) have been performed no clear conclusion so far
![Page 102: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/102.jpg)
FlashLinQ (Qualcomm)
• Vision: extend users’ sensing capabilities• Operates in licensed spectrum• All devices globally synchronized to a commonexternal timing source (e.g., GPS or cellular base stations)
• All devices operate in OFDMA (Orthogonal Frequency‐Division Multiple Access)
![Page 103: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/103.jpg)
103
Conclusion on wireless ad hoc networks
• Extensive research activity over the last decade
• Scalability is still an open issue• NIC and FlashLinQ show that vendors are considering this seriously
![Page 104: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/104.jpg)
Next week, 15:00 – 15:45Special session on career management
‐ How to choose my first job?‐ Should I do an MBA? A PhD?‐ Should I go to the US?‐ How about joining a start‐up company? Or even create a
new one?‐ How do I get the «big picture» of the job market?‐ I want to stay in Switzerland, are there interesting
companies here?
![Page 105: Module D3 - École Polytechnique Fédérale de Lausannemobnet.epfl.ch/slides/D3-MoreOnCellNW.pdf · • Considerable increase in transfer rates (compared with UMTS) • Market‐ready](https://reader033.vdocuments.site/reader033/viewer/2022042123/5e9e8406a97bad1c7a79e7b1/html5/thumbnails/105.jpg)
105
References on wireless ad hoc networks
Overview of ad hoc network routing protocols: seethe references mentioned at:http://en.wikipedia.org/wiki/Ad_hoc_networking
Research conference: ACM MobiHoc (especially for the theoretical aspects)
For FlashLinQ (Qualcomm):M. Scorson et al., Toward Proximity‐AwareInternetwoking, IEEE Wireless Comm., Dec. 2010