Mobile operators observ a considerable increase of the data traffic on their network. To face this increase, they use several mechanisms and different technologies. This presentation shortly describes these mechanisms.

1. A Survey of Available
Features for Mobile Traffic
Offload
Younes Khadraoui (Telecom Bretagne/IRISA)
Xavier Lagrange (Telecom Bretagne/IRISA)
Annie Gravey (Telecom Bretagne/IRISA)

2. 2
Outline
Introduction and Motivations
Offloading through femtocells
Offloading through Wi-Fi
 Loose coupling
 Tight coupling
 Very tight coupling
Conclusion

3. 3
Introduction and Motivations(1)
● New cellular access technologies:
(High Speed Packet Access (HSPA), Long Term Evolution (LTE));
● High bit rates
→ New services (streaming video, Voice over IP,etc);
→ Encourage the use of smartphones to access the internet;
Significant Increase of mobile data traffic !!!

4. 4
Introduction and Motivations (2)
[1] Ericsson, “Mobility report,” tech. rep., 2013.a

5. 5
Introduction and Motivations(3)
Deploy new base stations (BS)
→ increase inter-cell interference
→ high CAPEX and OPEX
Alternative solution:
Transfer a part of the traffic to other “cheaper” networks: Offloading
Two main offloading solutions:
➢Femtocells (Home eNodeB)
➢Wi-Fi networks
50% of global mobile data traffic will be offloaded to femtocells or Wi-
Fi networks by 2018 (17 exabytes/month); [2]
CAPEX=capital expenditure
OPEX=operational expenditure
[2]: [2] C. V. N. Index, “Global mobile data traffic forecast update, 2013-2018,”
US/solutions/collateral/ns341/ns525/ns537/ns705/ns827/white paper c11- 520862. html (Son eris¸im: 5 Febıs 2014),
2013.

6. ➢Few meters coverage
➢Same frequency band as
macro-BS
➢Seen as a regular BS
6
Offloading through femtocells
Femtocells:
Benefits:
✔ OPEX reduced from $60,000/year/macrocell to $200/year/femtocell [6];
Handover provided seamlessly ;
Disadvantages:
✗ Interferences with macro BS;
[6]:V. Chandrasekhar, J. Andrews, and A. Gatherer, “Femtocell networks: a survey,” Communications Magazine, IEEE, vol. 46,
no. 9,pp. 59–67, 2008.

7. 7
Offloading through Wi-Fi
Different types of architecture for integration of Wi-Fi and cellular network:
● Loose coupling;
● Tight coupling;
● Very tight coupling;

8. 8
Loose coupling(1)
2 IP addresses
2 protocol stacks
TCP connections
loss in case of
vertical handover
TCP=Transport Control Protocol

9. 9
Loose coupling(2)
Solutions for sessions continuity
Mobile IPv6 (MIPv6) based solution (Ip Flow Mobility (IFOM))

10. 10
Loose coupling(3)
Solutions for sessions continuity
SHIM6 based solution [16]
[16] A. Dhraief, Mobility and multihoming convergence. PhD thesis, (Institut Mines-Télécom-Télécom Bretagne-UEB), 2009.

11. 11
Loose coupling(4)
Solutions for sessions continuity
Stream Transport Control Protocol (SCTP) based solution[17]
[17] R. Stewart, Q. Xie, et al., “Rfc 4960,” stream control transmissionprotocol,” ietf,” Network Working Group
(October 2000), 2007.

12. 12
Loose coupling(5)
Solutions for sessions continuity
Multipath TCP (MPTCP) based solution [22]
[22] A. Ford, C. Raiciu, M. Handley, and O. Bonaventure, “Tcp extensions for multipath operation with multiple addresses,”
IETF MPTCP proposal-http://tools. ietf. org/id/draft-ford-mptcpmultiaddressed- 03. txt, 2011.

13. 13
Tight coupling
Tight coupling:
1 IP address
Seamless
vertical
handover

14. 14
Very tight coupling
Very Tight coupling[9]:
[9] X. Lagrange, “Very tight coupling between lte and wifi for advanced offloading procedures,” in WCNC
Workshop, Interference and design issues for futur heterogeneous networks, IEEE, 2014.

15. 15
Conclusion
✔ Increase of mobile data traffic on cellular networks
→ need for solutions;
✔ Alleviate traffic load on cellular network by offloading to other “cheaper”
network;
✔ Main offloading solutions: Femtocells and Wi-Fi;
✔ Different degrees of coupling Wi-Fi and cellular:
✔ Loose coupling
✔ Tight coupling
✔ Very tight coupling
✔ Session continuity issues

16. 16
Thank you!
Thank you for your attention !
Questions ?
Younes.khadraoui@telecom-bretagne.eu
Xavier.lagrange@telecom-bretagne.eu
Annie.gravey@telecom-bretagne.eu