Nafi Ul KarimID: 012-111-023 Masud Rana RashelID: 012-111-008
- IEEE 802.11 standard is named as Wi-Fi. The most popular are those defined by the 802.11b and 802.11g protocols - IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. - The 802.11 family consists of a series of over-the-air modulation techniques that use the same basic protocol.
802.11b and 802.11g control their interference and susceptibility to interference by using direct-sequence spread spectrum (DSSS) and orthogonal frequency- division multiplexing (OFDM) signaling methods, respectively. 802.11a uses the 5 GHz U-NII band, which for much of the world offers at least 23 non-overlapping channels; rather than the 2.4 GHz ISM frequency band, where all channels overlap.
handsets can make and receive calls from anywhere your phone can connect to a Wi-Fi network and saves on roaming charges. When a Voice over WiFi handset detects a wireless LAN, it can establish a secure IP connection through a gateway to a server on the carrier’s network. It presents the mobile core network as a standard cellular base station and the handset communicates over a secure connection using existing GSM/UMTS protocols.
When a mobile moves from a GSM to an 802.11 network, it appears to the core network as if it is simply on a different base station.
Alcatel AT&T Wireless Ericsson Motorola Nokia O2 Sony Ericsson Cingular
Unlicensed Mobile Access (UMA) technology enables access to GSM and GPRS mobile services over unlicensed spectrum using Bluetooth and Wi-Fi™. Highlights of the UMA Technology are: Seamless delivery of mobile voice and data services over wireless networks using unlicensed spectrum. Provides the same mobile identity on Cellular RAN and unlicensed wireless networks.
Seamless transitions (roaming and handover) between Cellular RAN and unlicensed wireless networks. Preserves investment in existing/future mobile core network infrastructure. Independent of underlying unlicensed spectrum technology (e.g. Wi-Fi™, Bluetooth™) Transparent to existing, standard CPE devices (e.g. access points, routers and modems)
Utilizes standard “always on" broadband IP access networks (e.g. DSL, Cable, T1/E1, Broadband Wireless, FTTH…) Security equivalent to current GSM mobile networks No impact to operations of Cellular RAN (e.g. spectrum engineering, cell planning,…)
Ga : The interface serves the CDRs (accounting records) which are written in the GSN and sent to the charging gateway (CG). This interface uses a GTP- based protocol, with modifications that supports CDRs (Called GTP' or GTP prime). Gb : Interface between the base station subsystem and the SGSN the transmission protocol could be Frame Relay or IP.
Gi : IP based interface between the GGSN and a public data network (PDN) either directly to the Internet or through a WAP gateway. Gn : IP Based interface between SGSN and other SGSNs and (internal) GGSNs. DNS also shares this interface. Uses the GTP Protocol. Gp : IP based interface between internal SGSN and external GGSNs. Between the SGSN and the external GGSN, there is the border gateway (which is essentially a firewall). Also uses the GTP Protocol.
Gr : Interface between the SGSN and the HLR. Messages going through this interface uses the MAP3 protocol.
The UMA Network (UMAN) consists of one or more access points (AP) and one or more UMA Network Controllers (UNCs), interconnected through a broadband IP network. Mobile Station (MS) versus Mobile Terminal (MT) Access Point (AP). The AP provides the radio link to the mobile station using unlicensed spectrum.
UMA Network Controller (UNC). The UNC appears to the core network as a GERAN base station subsystem (BSS). It includes a Security Gateway (SGW) that terminates secure remote access tunnels from the MS, providing mutual authentication, encryption and data integrity for signaling, voice and data traffic. A broadband IP network provides connectivity between the AP and the UNC. The IP transport connection extends all the way from the UNC to the MS, through an AP. A single interface, the Up interface, is defined between the UNC and the MS.
Co-existence with the GSM/GPRS Radio Access Network (GERAN) and interconnection with the GSM Core Network (CN) via the standardized interfaces defined for GERAN: A-interface for circuit switched services [TS 48.008] Gb-interface for packet switched services [TS 48.018]
The MS shall include dual mode (GSM and unlicensed) radios and the capability to switch between them. The MS supports either Bluetooth (using the Bluetooth PAN profile) or 802.11. The MS supports an IP interface to the access point. In other words, the IP connection from the UNC extends all the way to the MS.
The Access Point (AP) provides the radio link towards the mobile station using unlicensed spectrum. It connects through the broadband IP network to the UNC. The AP provides Bluetooth (PAN profile) [BTSIG3] or 802.11 access point functionality [802.11]. The AP does not provide any UMA-specific gateway functions, and any generic AP can be used to interconnect the MS to the UNC via the broadband IP network.
The Up interface is the interface between the UNC and MS. This interface operates over an IP transport network and relays GSM/GPRS signaling between the PLMN Core Network and the MS.
The salient features of the Up interface, with respect to the CS domain, are as follows: GSM protocols are carried transparently between the MS and MSC. This allows the MS to obtain all GSM services that it can receive through a GSM BSS, through the UMAN. GSM-RR protocol is replaced with a UMA-RR protocol. The unlicensed radio link presents different characteristics from that of the licensed GSM radio link, so the UMA-RR protocol is customized to take advantage of these characteristics. As in a GSM BSS, the UNC, acting like a BSC, terminates the UMA-RR protocol and inter-works it to the A-interface using BSS AP messaging.
The salient features of the CS domain user plane of the Up interface are as follows: Audio flows over the Up interface according to the RTP framing format defined in [RFC 3267] and [RFC 3551]. Support for GERAN codecs as specified in [TS 26.103] and for which a RTP framing format has been defined in IETF. AMR FR is the preferred codec type when operating in UMA mode.
The salient features of this part of the Up interface are as follows: GPRS LLC PDUs for signaling and higher layer protocols are carried transparently between the MS and SGSN. This allows the MS to obtain all GPRS services in the same way as if it were connected to a GERANBSS. GPRS-RLC protocol is replaced with an equivalent UMA-RLC protocol. Given the transport characteristics over Up interface the GPRS TBF abstraction is not applicable and reliability is ensured by TCP. Therefore the UMA-RLC is significantly lighter than GPRS-RLC. As in a GERAN BSS, the UNC, acting like a BSC, terminates the UMA-RLC protocol and inter-works it to the Gb-interface using BSS Gp.
UMA-RLC runs directly over UDP to leverage the IP bearer service.
The salient features of the PS domain user plane of the Up interface are as follows: GPRS LLC PDUs carrying data, and higher layer protocols, are carried transparently between the MS and SGSN. This allows the MS to derive all GPRS services the same as if it were in a GERAN BSS. All existing GPRS applications and MMI in the MS are unchanged. LLC PDUs are carried over UMA-RLC from the MS to the UNC, which relays it over to the SGSN using BSSGP messaging.
UMA supports security mechanisms at different levels and interfaces
The security mechanisms applied over the unlicensed radio interface are the authentication and encryption functions defined for the unlicensed mode radio interface protocols applied between the MS and AP. These mechanisms apply to voice, data and signaling over the radio interface. These mechanisms are out of scope of the current document. The security mechanisms over the Up interface protect signaling, voice and data traffic flows between the MS and the UNC from unauthorized use, data manipulation and eavesdropping; i.e., both authentication and encryption mechanisms are supported. The current document along with the [Stage 3] specifies the application of these mechanisms withappropriate references to the IETF protocols they are based on.
Authentication of the subscriber by the core network occurs between the MSC/VLR or SGSN and the MS and is transparent to the UNC; there is, however, cryptographic binding between the MS-CN authentication and the MSUNC authentication to prevent man-in-the-middle attacks. GPRS ciphering is the standard LLC layer ciphering that operates between the MS and the SGSN. These mechanisms are out of scope of the current document and are defined in [43.020]. Additional application level security mechanisms may be employed to secure the end-to-end communication between the MS and the application server or gateway. For example, the MS may run the HTTP protocol over an SSL session for secure web access. These mechanisms are out of scope of the present document.