FREE MOBILE CLOUD COMPUTING CONCEPTS - TRAINING_MODULES_WITH_TONS_OF_VIDEOS
LTE means Learning-Training-Evolution....(just
+++++++++++++++++++++++++++++++++ Definition: LTE (Long Term Evolution) is a wireless broadband technology designed to support roaming Internet access via cell phones and handheld devices.
Because LTE offers significant improvements over older cellular communication standards, some refer to it as a 4G
(fourth generation) technology along with WiMax.
With its architecture
based on Internet Protocol (IP) unlike many other cellular Internet protocols,
Long Term Evolution supports browsing Web sites, VoIP and other IP-based
services well. LTE can theoretically support downloads at 300 Megabits per second (Mbps) or more based on experimental trials. However, the actual network bandwidth available to an individual LTE subscriber sharing the service provider's network with other customers is significantly
Term Evolution service is only available in limited geographic areas, but telecommunications providers have been actively
expanding their LTE services.
Also Known As: Long Term Evolution, Super 3G +++++++++++++++++++++++++++++++++++++++++++++++
T-Mobile USA's merger
with MetroPCS, announced early this year, promises to create the
"leading value" wireless carrier in the U.S., according to officials from both companies.
Their claim is based primarily on the premise
that the merger will create a combined and expanded nationwide LTE wireless network -- using complementary spectrum -- and
that the new company will offer no-contract, unlimited-data service to customers at a low cost.
The combined entity would still be the nation's
fourth-largest wireless carrier in terms of subscribers -- behind AT&T, Verizon and Sprint. The proposed merger poses
the greatest threat to third-place Sprint, which has about 56 million customers. The merger is expected to be finalized in
the first half of 2013, and T-Mobile's customer base will grow from 33 million to 42 million subscribers when that happens.
By the end of 2013,
the nationwide contiguous LTE network of the combined company would be 40% bigger than what T-Mobile could offer alone.
There will be a focus
on major metropolitan areas, such as New York, Los Angeles and Dallas, said John Legere, CEO of T-Mobile, who will become
the CEO of the combined company.
Also, with the combined resources of MetroPCS and T-Mobile, the new network will be 20% denser, because it will have
more coverage that takes advantage of a larger number of towers that use a fatter wireless channel than what T-Mobile's LTE
network would have had, he said.
Noting that the merger would close the gap between T-Mobile and Sprint, Legere said in a conference call with reporters:
"We're not just here to compete, we're here to win.... This has the potential to be a game-changer."
Later, he said that
while the combined entity would offer various service plans to customers, including more traditional two-year contract options,
he also vowed that it would be "the leading provider of no-contract services."
In the wireless market, no-contract services
are growing at an annual rate that is three times faster than the annual growth rate of contract services, he noted.
Leger also reached out
to enterprises wrestling with the trend of employees who want to use their personal smartphones on the job. The various service plans from the merged entity will be combined with bring-your-own-device (BYOD)
plans, he said, adding, "We hear [customers] loud and clear."
Some analysts and investors were concerned that by merging with
MetroPCS, T-Mobile will incur added costs because it will have to convert MetroPCS's CDMA cell towers to support the GSM service
that T-Mobile offers. Both companies are committed to 4G LTE, a common technology platform, but the conversion of 3G CDMA
towers to 3G GSM will be necessary in order to support customers who will need 3G service when they can't find a 4G LTE signal.
LTE is a data-only network, which means GSM will be needed to transmit voice calls for a period of time.
Officials said the CDMA-to-GSM conversion
effort will start as soon as the merger is finalized in 2013, and all MetroPCS customers will be converted to GSM by the end
of 2015. MetroPCS customers get new phones more often than customers of other carriers -- at a rate of 50% to 65% a year --
and that will speed the conversion, Legere said.
"We expect minimal [MetroPCS] customer losses and will be managing this very carefully,"
Legere said. "To MetroPCS customers: You will not be abandoned."
In the wake of T-Mobile's failed 2011 merger with AT&T, the
announcement of a merger with MetroPCS sounded like good news to analysts.
T-Mobile has been losing customers, and gaining spectrum via the
MetroPCS merger is a less costly way to expand its network than buying more spectrum on its own, analysts said.
"This merger makes
the combined company attractive against Sprint," said Jack Gold, an analyst at J.Gold Associates. "T-Mobile needs
more customers but is losing them, and is still just about half the size of Sprint. So it has become a question of spending
a ton of money to upgrade to LTE, but how do you recoup those costs without subscribers?"
The merger is "obviously bad news for
Sprint," and other no-contract services, even those offered by the two largest carriers, AT&T and Verizon, said Julien
Blen, an analyst at Infonetics.
Under the terms of the announced deal, T-Mobile's parent, Deutsche Telekom, essentially retains a 74% share of the
combined company and will provide $500 million in revolving credit to help the new entity. In the conference call, DT CEO
Rene Obermann said the company remains committed to "creating a sustainable and financially viable national challenger
in the U.S." and added that the deal "strengthens our position in the U.S. market."
MetroPCS shareholders will receive $1.5 billion
in cash and 26% of the new company.
Legere said the merger will accelerate T-Mobile's rise to prominence in the U.S. wireless market. "This is a
deal not about surviving ... This is about thriving," he said. ++++++++++++++++++++++++++++++++++++++++++++++
If you live in Houston
and are considering buying an iPhone 5 for its zippy LTE cellular data connection, you may want to think twice before selecting
AT&T as your carrier.
For the past few weeks, current users of AT&T’s 4G, LTE network have experienced intermittent connection
issues in the Houston area. Based on postings in the carrier’s support forums and discussions on Twitter, customers
using LTE-capable AT&T smartphones are having difficulty connecting to the network during workday hours.
An AT&T spokesperson
said the company is looking into the complaints, but offered no specifics as to a cause or when the problem would be fixed:
customers may be experiencing issues with data service in the Houston area. A team of engineers is investigating this issue,
and we apologize for any inconvenience to our customers.”
Based on descriptions in this discussion on AT&T’s
support forum, the issue appears to begin in the early morning, as people are going to work, and lasts throughout
the day. In the evening, after rush hour, it goes away. This comment is typical of the pattern:
I work a 6:30-3:30 shift
just outside of the beltway, and very early in the morning, my data works great, just like it should. Then about
an hour into my morning, when traffic starts picking up just a bit, I’m plagued with data issues again for the remainder
of the day. Then late at night, around 11:00 or 12:00 it starts to work fine again.
This may hint at a congestion issue, a problem
that has plagued AT&T’s 3G network, particularly in large cities like New York and San Francisco.
The first report
in the discussion is dated Sept. 8:
For the past couple of days LTE on my one x has been pretty much unusable
in Houston. The signal bar shows normal decent LTE signals but actual data transfer constantly times out or stops in the middle.
Speedtest shows 20+ mbps when the transfer works but would stop to a complete halt every few seconds. Called CS and confirmed
that my account isn’t being throttled. Anyone else having same problems?
Forum posters report that forcing their phones
to use AT&T’s HSPA+ network instead results in steadier, reliable connections. Of course, that network is much slower
than LTE . . . at least, when LTE is working as it should.
Several of the forum members say the issue has been going on for
several weeks. Others mention going into AT&T stores and being told by employees that a lot of customers have
walked in with the same complaint. Switching out SIM cards and even changing handsets doesn’t relieve
most of the posters in the forum reporting having Android phones, the issue also affects other platforms, including
Nokia’s Lumia 900, an LTE-capable Windows Phone device.
Responding to a query on Twitter, Lumia 900 user
Jeff Kibuule said he has been experiencing the issue:
@dsilverman @ATT My Lumia 900 has had intermittent connections...
doesn't work, then I get 20Mbps... off and on. =/
Kibuule said he even changed phones to a Samsung Galaxy S III but still
had problems connecting to AT&T’s LTE.
The pattern – LTE works fine in the off hours, then bogs down when
people are awake and using their phones – hints at data congestion, an issue that has notoriously plagued AT&T’s
3G network in large cities. If that is the cause, it’s only going to get worse after Sept. 21, when Apple ships the
LTE-enabled iPhone 5. Some analysts expect Apple will sell as many as 10 million units in the first weekend,
and a lot of those phones will end up in hands of Houstonians.
Hopefully, AT&T will have the problem fixed by then.
An AT&T spokesperson says via email that the problem has been fixed.
Some customers in Houston may have recently
experienced intermittent issues with mobile data service. AT&T technicians migrated traffic from the small portion of
the network impacted, and testing shows resolution of the issue. We apologize for any inconvenience to our customers.
I asked the spokesperson
if there was an exact cause, and this was the response:
Dwight, we are investigating the root cause, but due to our redundant
and flexible mobile network architecture, we were able to isolate the problem and resolve the impact to customers. Only a
limited number of mobile data customers were impacted. ++++++++++++++++++++++++++++++++
LTEi (Long Term Evolution) is initiated by 3GPPi to improve the mobile phone standard to cope with future technology evolutions and needs.
What is goal of LTE?
The goals for LTE include improving spectral efficiency, lowering costs, improving services, making use of new spectrum
and reformed spectrum opportunities, and better integration with other open standards.
What speed LTE offers?
LTE provides downlink peak rates of at least 100Mbit/s, 50 Mbit/s in the uplink and RAN (Radio Access Network) round-trip
times of less than 10 ms.
What is LTE Advanced?
LTE standards are in
matured state now with release 8 frozen. While LTE Advanced is still under works. Often the LTE standard is seen as 4G standard
which is not true. 3.9G is more acceptable for LTE. So why it is not 4G? Answer is quite simple - LTE does not fulfill all
requirements of ITU 4G definition.
Brief History of LTE Advanced: The ITU has introduced the term IMT Advanced to identify
mobile systems whose capabilities go beyond those of IMT 2000. The IMT Advanced systems shall provide best-in-class performance
attributes such as peak and sustained data rates and corresponding spectral efficiencies, capacity, latency, overall network
complexity and quality-of-service management. The new capabilities of these IMT-Advanced systems are envisaged to handle a
wide range of supported data rates with target peak data rates of up to approximately 100 Mbit/s for high mobility and up
to approximately 1 Gbit/s for low mobility.
What is LTE architecture?
evolved architecture comprises E-UTRAN (Evolved UTRAN) on the access side and EPC (Evolved Packet Core) on the core side.
The figure below shows the evolved system architecture
What is EUTRAN?
The E-UTRAN (Evolved UTRAN) consists of eNBs, providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane
(RRC) protocol terminations towards the UE. The eNBs are interconnected with each other by means of the X2 interface. The
eNBs are also connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility
Management Entity) by means of the S1-MME and to the Serving Gateway (S-GW) by means of the S1-U.
What are LTE Interfaces?
The following are LTE Interfaces : (Ref: TS 23.401 v 841)
S1-MME :- Reference point for the control
plane protocol between E-UTRAN and MME.
S1-U:- Reference point between E-UTRAN and Serving GW for the per bearer user plane tunnelling and inter eNodeB path
switching during handover.
It enables user and bearer information exchange for inter 3GPP access network mobility in idle and/or active state.
S4:- It provides related control and mobility
support between GPRS Core and the 3GPP Anchor function of Serving GW. In addition, if Direct Tunnel is not established, it
provides the user plane tunnelling.
S5:- It provides user plane tunnelling and tunnel management between Serving GW and PDN GW. It is used for Serving
GW relocation due to UE mobility and if the Serving GW needs to connect to a non-collocated PDN GW for the required PDN connectivity.
S6a:- It enables transfer of subscription
and authentication data for authenticating/authorizing user access to the evolved system (AAA interface) between MME and HSS.
Gx:- It provides transfer of (QoS) policy
and charging rules from PCRF to Policy and Charging Enforcement Function (PCEF) in the PDN GW.
S8:- Inter-PLMN reference point providing user and control plane
between the Serving GW in the VPLMN and the PDN GW in the HPLMN. S8 is the inter PLMN variant of S5.
S9:- It provides transfer of (QoS) policy
and charging control information between the Home PCRF and the Visited PCRF in order to support local breakout function.
S10:- Reference point between MMEs for MME
relocation and MME to MME information transfer.
S11:- Reference point between MME and Serving GW.
S12:- Reference point between UTRAN and Serving GW for user plane tunnelling when Direct
Tunnel is established. It is based on the Iu-u/Gn-u reference point using the GTP-U protocol as defined between SGSN and UTRAN
or respectively between SGSN and GGSN. Usage of S12 is an operator configuration option.
S13:- It enables UE identity check procedure between MME and EIR.
SGi:- It is the reference point between the
PDN GW and the packet data network. Packet data network may be an operator external public or private packet data network
or an intra operator packet data network, e.g. for provision of IMS services. This reference point corresponds to Gi for 3GPP
Rx:- The Rx
reference point resides between the AF and the PCRF in the TS 23.203.
SBc:- Reference point between CBC and MME for warning message delivery and
What are LTE Network elements?
eNB eNB interfaces with the UE and hosts the PHYsical (PHY), Medium Access Control (MAC),
Radio Link Control (RLC), and Packet Data Control Protocol (PDCP) layers. It also hosts Radio Resource Control (RRC) functionality corresponding to the control plane. It performs many functions including radio resource management, admission
control, scheduling, enforcement of negotiated UL QoS, cell information broadcast, ciphering/deciphering of user
and control plane data, and compression/decompression of DL/UL user plane packet headers.
Mobility Management Entity manages and stores UE context (for idle state: UE/user identities,
UE mobility state, user security parameters). It generates temporary identities and allocates them to UEs. It checks the authorization
whether the UE may camp on the TA or on the PLMN. It also authenticates the user. Serving Gateway The SGW routes and forwards user
data packets, while also acting as the mobility anchor for the user plane during inter-eNB handovers and as the anchor for
mobility between LTE and other 3GPP technologies (terminating S4 interface and relaying the traffic between 2G/3G systems
and PDN GW).
Packet Data Network Gateway The PDN GW provides connectivity to the
UE to external packet data networks by being the point of exit and entry of traffic for the UE. A UE may have simultaneous
connectivity with more than one PDN GW for accessing multiple PDNs. The PDN GW performs policy enforcement, packet filtering
for each user, charging support, lawful Interception and packet screening.
What are LTE protocols
In LTE architecture, core network includes Mobility Management
Entity (MME), Serving Gateway (SGW), Packet Data Network Gateway (PDN GW) where as E-UTRAN has E-UTRAN NodeB (eNB).
VoLGA stands for "Voice over LTE via Generic Access". The VoLGA
service resembles the 3GPP Generic Access Network (GAN). GAN provides a controller node - the GAN controller (GANC) - inserted
between the IP access network (i.e., the EPS) and the 3GPP core network.
The GAN provides an overlay access between
the terminal and the CS core without requiring specific enhancements or support in the network it traverses. This provides
a terminal with a 'virtual' connection to the core network already deployed by an operator. The terminal and network thus
reuse most of the existing mechanisms, deployment and operational aspects.
What is CS Fallback
LTE technology supports packet based services only, however 3GPP does specifies
fallback for circuit switched services as well. To achieve this LTE architecture and network nodes require additional functionality,
this blog is an attempt to provide overview for same.
In LTE architecture, the circuit switched (CS) fallback in EPS
enables the provisioning of voice and traditional CS-domain services (e.g. CS UDI video/ SMS/ LCS/ USSD). To provide these
services LTE reuses CS infrastructure when the UE is served by E UTRAN.
How does LTE Security works?
The following are some of the principles of 3GPP E-UTRAN security based on 3GPP Release 8 specifications:
keys used for NAS and AS protection shall be dependent on the algorithm with which they are used.
The eNB keys are cryptographically separated from the EPC keys
used for NAS protection (making it impossible to use the eNB key to figure out an EPC key).
The AS (RRC and UP) and NAS keys are derived in the EPC/UE from
key material that was generated by a NAS (EPC/UE) level AKA procedure (KASME) and identified with a key identifier (KSIASME).
The eNB key (KeNB) is sent from the EPC to
the eNB when the UE is entering ECM-CONNECTED state (i.e. during RRC connection or S1 context setup).
does measurements work in LTE?
In LTE E-UTRAN measurements to be performed by a UE for mobility
are classified as below
Intra-frequency E-UTRAN measurements
Inter-frequency E-UTRAN measurements
Inter-RAT measurements for UTRAN and GERAN
Inter-RAT measurements of CDMA2000 HRPD or
What is Automatic Neighbour Relation?
According to 3GPP specifications,
the purpose of the Automatic Neighbour Relation (ANR) functionality is to relieve the operator from the burden of manually
managing Neighbor Relations (NRs). This feature would operators effort to provision.
How does Intra E-UTRAN Handover is performed?
Intra E-UTRAN Handover is used to hand over a UE from a source eNodeB to a target eNodeB using X2 when the MME is
unchanged. In the scenario described here Serving GW is also unchanged. The presence of IP connectivity between the Serving
GW and the source eNodeB, as well as between the Serving GW and the target eNodeB is assumed.
The intra E-UTRAN
HO in RRC_CONNECTED state is UE assisted NW controlled HO, with HO preparation signalling in E-UTRAN.
How does policy control
and charging works in LTE?
A important component in LTE network is the policy and charging
control (PCC) function that brings together and enhances capabilities from earlier 3GPP releases to deliver dynamic control
of policy and charging on a per subscriber and per IP flow basis.
LTE Evolved Packet Core (EPC) EPC includes a PCC architecture that
provides support for fine-grained QoS and enables application servers to dynamically control the QoS and charging requirements
of the services they deliver. It also provides improved support for roaming. Dynamic control over QoS and charging will
help operators monetize their LTE investment by providing customers with a variety of QoS and charging options when choosing
The LTE PCC functions include:
PCRF (policy and charging rules function) provides policy control
and flow based charging control decisions.
PCEF (policy and charging enforcement function) implemented in the serving gateway, this enforces gating and QoS
for individual IP flows on the behalf of
the PCRF. It also provides usage measurement to support charging
OCS (online charging system) provides credit management and grants credit
to the PCEF based on time, traffic volume or chargeable events.
OFCS (off-line charging system) receives events from the PCEF and generates charging data
records (CDRs) for the billing system.
What is SON & how does it work in LTE?
Self-configuring, self-optimizing wireless networks is not a new concept but as the mobile networks are evolving
towards 4G LTE networks, introduction of self configuring and self optimizing mechanisms is needed to minimize operational
efforts. A self optimizing function would increase network performance and quality reacting to dynamic processes in the network.
would minimize the life cycle cost of running a network by eliminating manual configuration of equipment at the time of deployment,
right through to dynamically optimizing radio network performance during operation. Ultimately it will reduce the unit cost
and retail price of wireless data services.
How does Network Sharing works in LTE?
3GPP network sharing architecture allows different core network operators to connect to
a shared radio access network. The operators do not only share the radio network elements, but may also share the radio resources
Read Network Sharing in LTE
How does Timing Advance (TA) works in LTE?
In LTE, when UE wish to establish RRC connection
with eNB, it transmits a Random Access Preamble, eNB estimates the transmission timing of the terminal based on this. Now
eNB transmits a Random Access Response which consists of timing advance command, based on that UE adjusts the terminal transmit
The timing advance is initiated from E-UTRAN with MAC message that implies and adjustment of the timing advance.
many operators have committed for LTE?
List of operators committed for LTE has been
compiled by 3GAmericas from Informa Telecoms & Media and public announcements. It includes a variety of commitment levels
including intentions to trial, deploy, migrate, etc. ++++++++++++++++++++++