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wireless communication seminar by nisha menon

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  1. 1. FEMTOCELLS : Past ,Present & Future Nisha Menon K Mtech Communication Engg 25 October 2013 1
  2. 2. Outline Introduction  Motivation  Working of femtocell  Femtocell requirements  Features of femtocell  Challenges  Benefits of femtocell  Conclusion  Reference  25 October 2013 2
  3. 3. Introduction The wireless capacity has doubled every 30 months since 1957 – 25X improvement from wider spectrum – 5X improvement by dividing the spectrum into smaller slices – 5X improvement by designing better modulation schemes • The main problem of current cellular network – The expensive deployment cost of network infrastructure – Low signal strength received from an outdoor BS inside a building 25 October 2013 3
  4. 4. Motivation • Some studies on wireless usage show – More than 50% voice calls and more than 70% data traffic are originated indoor • Win-Win strategy – Higher data rate and reliability for subscribers (User) – Reduced amount of traffic on expensive macrocell network (Operator) 25 October 2013 4
  5. 5. Macro cells Femto cells Cell types Micro cells Pico cells 25 October 2013 5
  6. 6. Macro cell Micro cell Pico cell Femtocel l 25 October 2013 6
  7. 7. What is Femtocell • Femtocells are small mobile towers at home. • Femtocells are used to provide licensed indoor coverage. • Femtocells combine the internet access technologies like DSL and cable with mobile technologies. • It connects the operator via internet providing excellent radio conditions. 25 October 2013 7
  8. 8. Working of femtocell 25 October 2013 8
  9. 9. How does femtocell work 25 October 2013 9
  10. 10. Femtocell Requirements Femtocell itself Internet router to enable the data to be passed to and from the femtocell via the Internet Internet link Mobile telecommunications service provider Core network gateway The two key elements of the system are the femtocell which is installed within the user premises and also the network gateway that provides the link from the Internet into the telecommunications network. 25 October 2013 10
  11. 11. Features of Femtocell • • • • • • • Operates in the licensed spectrum Uses fixed broadband connection for backhaul Principally intended for home and SOHO Lower cost than PicoBS Smaller coverage (low power) than PicoBS Self Organizing Network Higher density 25 October 2013 11
  12. 12. Femtocell Access Control Closed access Open access Hybrid access 25 October 2013 12
  13. 13. Femtocell Standardisation In 3GPP terminology, a Home Node B (HNB) is a 3G femtocell.  Home eNode B (HeNB) is an LTE femtocell.  25 October 2013 13
  14. 14. Challenges Challenges Economic and regulatory issues Technical challenges Cell association and biasing Interference Mobility and soft handover Health issue Spectrum issue Regulatory aspects 25 October 2013 14
  15. 15. Cell association and biasing  Irregular deployment will incur inevitable interference 25 October 2013 15
  16. 16. Interference analysis Random placements of FAPs.  Cochannel spectrum sharing between femtocells and macrocells  Two types of interferences  • Cross layer interference • Situations in which the aggressor (FAP) and the victim (macro cell user) of interference belong the different network layers • Co layer interference • Here the aggressor(FAP) and the victim(neighbour femto cell user) belong to same network layer 25 October 2013 16
  17. 17. Proposed methods to overcome interference  Interference cancellation technique ◦ Disregarded due to errors in the cancellation process  Use of sectoral antennas at FAP ◦ Reducing interference by decreasing the number of interferers   Dynamic selection of predefined antenna patterns Interference avoidance (power and subchannel management) ◦ Good alternative 25 October 2013 17
  18. 18. Handover  Handover in femtocells highly depends upon the access mode being used. The number of handover is very large in the case of open access, while are reduced in closed and hybrid access modes  Soft handover is not supported by femtocells Inbound: handover occurs from the macro-cell or standard cellular network to the femtocell.  Outbound: handover occurs from the femtocell to the macro-cell or standard cellular network.  Femtocell to femtocell: There will be situations where handover will occur between one femtocell and another close by. This will be commonplace in offices that may have a number of femtocells to give continuous coverage within a building.  25 October 2013 18
  19. 19. Femtocell spectrum issues Radio spectrum is a particularly scarce resource, especially when large amounts of data are required. Planning the available spectrum so that it can be used with the possible huge numbers of femtocells can require careful attention, although in some instances single channel operation with main base stations may be required 25 October 2013 19
  20. 20. Femtocell regulatory issues: Femtocells operate in licensed or regulated spectrum. Unlike Wi-Fi which operates in unlicensed spectrum, femtocells need regulatory approval. The spectrum and radio regulations vary from one country to the next and therefore regulations may need to be changed in each country. International agreement may also be required, because private individuals may take femtocells from one country to the next. 25 October 2013 20
  21. 21. Femtocells and health issues: As a femtocell is a cellular base station, there could be public concern regarding the levels of RF radiation received The power levels emitted by femtocells are small - no greater than most Wi-Fi access points which are common in very many homes. As a result it is not believed by the industry in general that there are any health issues that should cause any concern. 25 October 2013 21
  22. 22. BENEFITS OF FEMTOCELLS Technical Advantages      Low Cost Low Power Easy to Use Compatibility & Interoperability Deployment Customer’s point of view     Increased Indoor Coverage Load sharing Better Voice Quality Better Data/Multimedia Experience Wireless Operator’s point of view    Lower CAPEX and OPEX Increased network capacity Newer Revenue Opportunities 25 October 2013 22
  23. 23. Today Voice coverage Deep data coverage Capacity Offloads Tomorrow Public access Femtocells may begin to proliferate in coffee shops Corporate malls and other hotspots Begin to proliferate corporate offices ensuring employees full access to high Services quality voice and fast home mobile data automation Integration Sms alerts A feature addition to set top box or integrated with a dsl modem 25 October 2013 23
  24. 24. Conclusion  Unsatisfactory coverage and the increasing number of application are two driving forces for femtocell development  Femtocells have the potential to provide high-quality network access to indoor users at low cost – Improve coverage – Provide huge capacity gain  Femtocells are considered to be the solution to meet the future needs for high data rates and capacity in wireless cellular networks.  The femtocells would also face tough competition from the already established Wi-Fi technology and the operators need to provide cheap services in order to capture the future indoor wireless access market. 25 October 2013 24
  25. 25. Reference  Jeffrey G Andrews, Holger Claussen, Mischa Dohler, Sundeep Rangan, Mark C Reed, “Femtocells: Past, Present and Future” IEEE Communications Magazine, vol. 30,April 2012  V. Chandrasekhar, J. G. Andrews, and A. Gatherer, “Femtocell networks:a survey,” IEEE Communications Magazine, vol. 46, no. 9, pp.59–67, September 2008.  H. Claussen, L. T. W. Ho, and L. G. Samuel, “An overview of the femtocell concept,” Bell Labs Technical Journal, vol. 13, no. 1, pp. 221–245, May 2008  P. Xia, V. Chandrasekhar, and J. G. Andrews, “Open vs. closed access femtocells in the uplink,” IEEE Transactions on Wireless Communications, vol. 9, no. 10, pp. 3798 – 3809, Dec. 2010  Informa Telecoms & Media, “Femtocell Market Status,” Femtoforum whitepaper, 2011. 25 October 2013 25
  26. 26. Queries ??? 25 October 2013 26
  27. 27. Thank you 25 October 2013 27