Capacity Limit Problem in 3G Networks

By

Fahd Ahmad Saeed

Problem• 3G network will not be able to withstand the bandwidth intensive

services being planned to be offered by mobile operators, even with only a small number of subscribers utilizing the service within a service area.

• 3G wireless technology was never built to deliver the streaming media services

• The bandwidth consumed for a certain media will increase exponentially as users requesting the certain media increases within a cell. As more subscribers start using these services, more base stations are needed to boost the shared bandwidth.

• Currently mobile operators have to depend on additional overlay networks to broadcast high bandwidth media

Background• 3G networks

– W-CDMA• UMTS• FOMA

– cdma2000 1x EVDO, 3x– TD-SCDMA– UMA– EDGE

• Supports data rates from 384kbps to 2Mbps• Packet switched data services• Use Licensed spectrum, no spare spectrum• No proven mathematical formula on how to handle capacity

problems• Network divided into cells• Each cell shares bandwidth

Background

http://www.us.anritsu.com/downloads/files/11410-00378.pdf

Background

http://www.ieee-infocom.org/Posters/1568980522_Passive%20Tomography%20of%20a%203G%20Network/ricciato-proposal_infocom06.pdf

Possible Solutions• 3GPP/3GPP2 is working on modifying 3G, called MBMS

(Multimedia Broadcast and Multicast Standard), will be available in networks in 2007.– Doesn’t require additional spectrum or licensing. coverage will be

identical to conventional 3G networks. – Capacity needs to be set aside that could be used to sell end to end

voice and data. Limited number of channels, due to capacity limitation.• Building dedicated broadcast networks to add additional channels,

such as DVB-H, DMB and MediaFlo.– Will require mobile operators to upgrade equipment and consumers to

buy new handsets.• Add more cells to the network to decrease cells covered area to

support more bandwidth. Expensive.• Using Smart Antennas: directs radio signal to intended target, rather

than broadcasting it to everyone. Utilizes spatial separation.

Proposed Solution

• Use a combination of WiFi, 3G with strategically placing Smart Antennas in dense cell usage areas.

• Seamless handshaking between WiFi and 3G.• Pricing: Volume of Data transmitted through

WiFi is tracked within the handheld device and transmitted to the operator with a certain delay – End of session?

Research• After extensive research on the problem, it was found that the

proposed solution has already been looked at and the technology developed by Nortel and has been successfully tested in Japan.

http://informationweek.com/story/showArticle.jhtml?articleID=164901785

• Lucent Technologies also successfully tested the handoff between 3G networks and WiFi seamlessly.

http://www.mobile.commerce.net/story.php?story_id=2195

• IEEE 802.21 standard will try to make it possible to roam from any 802- based network to another, and will also let them roam to 3G cellular network.

• Nokia demonstrated its seamless handoff of voice and data services between WiFi and 3G networks at the CTIA Wireless 2006.

http://www.pdastreet.com/articles/2006/4/2006-4-14-Nokia-Demos-Cellular.html

Handoff

http://web.ptc.org:8080/library/proceedings/PTC2003/program/private/wednesday/w13/w132_waters.pdf

3G vs. WiFi

• Combination of the two technologies prevents the capacity bottleneck associated with 3G network. If a 3G cell is being overloaded, the call or data connection can be handed off to a WiFi Access Point.

• WiFi is less expensive to deploy then 3G networks and can be deployed for thousands of dollars vs. millions.

• Since WiFi has a short range, but more bandwidth compared to 3G, each technology will compliment each other.

Problems with the Proposed Solution

• Pricing model between WiFi and mobile operators (3G). How is the consumer going to get billed.

• Security within unsecured WiFi networks.• Seamless handoff will not occur between

secured WiFi networks and 3G networks, if the network key (WPA, WEP) is not pre-programmed.

• Maintaining Qos between networks.

Conclusion• The proposed solution attractive, if the pricing and security problems

are resolved between handoffs between networks.

• A fair pricing model is needed to address roaming between networks.

• A secure public key encryption scheme supported between WiFi and 3G networks is needed to allow seamless roaming between the two networks.

• Some good article about integrated support between heterogeneous networks arehttp://middleware05.objectweb.org/WSProceedingsMPAC05/a15-bellavista.pdf

http://web.ptc.org:8080/library/proceedings/PTC2003/program/private/wednesday/w13/w132_waters.pdf

References• http://www.medialab.co.nz/assets/downloads/Seamless%20Handoff%20Between%20802.11b%20and%2

0CDMA2000%20Networks.pdf

• http://middleware05.objectweb.org/WSProceedingsMPAC05/a15-bellavista.pdf

• http://www.pdastreet.com/articles/2006/4/2006-4-14-Nokia-Demos-Cellular.html

• http://www.mobile.commerce.net/story.php?story_id=2195

• http://informationweek.com/story/showArticle.jhtml?articleID=164901785

• http://www.ieee-infocom.org/Posters/1568980522_Passive%20Tomography%20of%20a%203G%20Network/ricciato-proposal_infocom06.pdf

• http://www.us.anritsu.com/downloads/files/11410-00378.pdf

• http://www.ecsl.cs.sunysb.edu/tr/handoff.pdf

• http://www.x-changemag.com/articles/321coverstory.html

• http://web.ptc.org:8080/library/proceedings/PTC2003/program/private/wednesday/w13/w132_waters.pdf