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31 Οκτ 2013 (πριν από 4 χρόνια και 8 μέρες)

108 εμφανίσεις


Nafi

Ul

Karim

ID: 012
-
111
-
023



Masud

Rana

Rashel

ID: 012
-
111
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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.







Thanks A Lot Everyone.