Unlicensed Mobile Access (UMA )

1
Unlicensed Mobile Access (UMA )

• Introduction and Overview
• Andrew Santarelli
• David Schraitle
• Matt Eberts
• Miguel Ibarra
• Mohammed Shareef

2
Contents

• Introduction
• History
• How it works
• Security
• Advantages Disadvantages
• Service Deployment

3
UMA History

• Development of UMA inspired by the rapid
  deployment of broadband and wireless LANs within
  homes.
• Wanted to create a high bandwidth, low-cost
  wireless access network.
• Several major leading mobile operators and
  network equipment vendors collaborated and formed
  the Unlicensed Mobile Access Consortium (UMAC),
  to promote the Unlicensed Mobile Access (UMA)
  technology and develop specifications for it.

4
Development

• Companies Involved
• Cingular
• Motorola
• Nokia
• Sony Ericsson
• T-Mobile US

• These companies developed the first set of UMA
  specifications and published them in September
  2004.
• The specifications were given to the 3rd
  Generation Partnership Project (3GPP).
• Eight months later in April 2005, the
  specifications were included into their framework
  inside the 3GPP release 6 and renamed Generic
  Access Network (GAN).

5
Timeline
6
How UMA works
7
Handing Off Connection

• UMA device on cellular network
• Finds suitable Wi-Fi network in range
• Device will analyze network and determine if
  connect or not
• Connect to UMA controller and negotiate switch
  with cell network

8
Inside UMA

• UMA protocol stored within the radio of the
  device.
• Tunnels through other radio layers to get to
  mobile network
• Requires an IP interface to connect to the
  internet
• IPsec module deals with tunnel to UMA controller

9
VoIP

• Transferring voice over internet is a costly
  endeavor
• Codecs used in traditional VoIP clients are
  costly
• AMR (Adaptive Mult-Rate) used to provide cheap,
  effective transmission
• Same as used already on phones
• Already optimized for low power consumption

10
UMA security
11
UMA Security
AUTHENTICATION CONFIDENTIALITY INTEGRITY
AUTHENTICATION Internet Key Echange version 2
(IKEv2) -choose your own algorithm Extensible
Authentication Protocol (EAP)
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UMA Security
AUTHENTICATION CONFIDENTIALITY INTEGRITY

• CONFIDENTIALITY
• IPsec
• Confidentiality algorithms
• AES with 128bit key length
• 3DES
• NULL encryption

IPsec (IPv4) -----------------------------------
------------------------------ new IP header
  original IP header      ESP    ESP  
(any options) ESP (any options)    
TCPDataTrailerAuth   ------------------------
-----------------------------------------        
            lt------encrypted-------------------gt
                lt-----authenticated-------------
-------gt
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UMA Security
AUTHENTICATION CONFIDENTIALITY INTEGRITY

• INTEGRITY
• Algorithms
• HMAC-SHAI-96
• HMAC-MD5
• AES-XCBC-MAC-96

14
UMA Security Weaknesses

• IMSI Encrypted, but transferred with Network
  Access ID (NAI)
• Mobile Station Authentication OPTIONAL (MITM
  attack)
• DoS Attack

15
UMA Security Comparison with Other Technologies
16
Advantages and disadvantages
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For Consumers

• Single number for home and mobile calls
• Calls through wireless LAN's, can deploy your own
  home coverage
• Greatly reduced roaming charges
• One provider for home internet and cell phone
  coverage

18
For Providers

• Deploying Wi-Fi hotspots is cheaper than
  deploying WAN's
• Reduces load on cellular networks, shifting some
  burden to internet infrastructure
• Able to shift calls onto the cheaper internet
  infrastructure

19
Disadvantages

• UMA-compatible handsets are more expensive and
  less common
• UMA-enabled phones require two active
  transceivers to handle seamless call-switching
• Despite all this, it's still not as cheap as
  straightforward VOIP protocols

20
Service deployment
21
Service Deployment Surveying

• A full site survey is necessary to determine
  coverage planning and WiFi channel planning
• The survey revolves around finding the RF
  characteristics of the weakest client in the
  network, specifically its transmit power
• Design Access Points to match Radio coverage of
  the dual-mode phone
• WiFi performance is solely dependent on the
  phone's signal to the Access Points, similar to a
  phone's signal from the tower affecting calling
  ability

22
Cisco UMA Deployment
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UMA Deployment

• Wireless Control System gives support to
  standalone Access Points and also Wireless LAN
  Controller
• Wireless Control System also provides statistics
  on calls being made, WiFi Channel performance and
  coverage planning
• Access Points improve call quality and WiFi
  channel capacity to phones which are unable to to
  support 802.11 1n protocol

24
Conclusion and questions