Telecommunications Blog

WiMAX (Worldwide Interoperability for Microwave Access) ( 802.16 - 802.16e ).WIMAX was developed to promote conformance and interoperability of the IEEE 802.16 standard (Wireless MAN).


we will learn how we can planning a wimax network but first we should know some important things .

 
Frequency Planning :

         • The frequency re-use is extremely important in reducing the interference and therefore increasing the capacity
         • Off-the-shelf frequency assignment do not minimize the deployment cost for your system.
         • An optimum frequency assignments can be applied by considering
         • Site locations
         • Power levels
         • User distribution
         • Spectrum availability
         • Geography and building characteristics.


Site Features Optimization

         • Number of antennas
         • Antenna directions
         • Antenna heights
         • Antenna powers
         • Antenna tilts
         • Number of channels
         • Frequency of channels
         • OFDM Parameters
         • Cyclic prefix
         • Number of subchannels
         • Subchannelization rates
         • Available modulations
         • Handover parameters
         • MIMO settings
         • Uplink / Downlink traffic ratios
         • Voice over IP related issues
         • Backhaul planning: fiber, minilink, HDSL…. capacity issues

The following essential landmark may be the standardization associated with LTE-Advanced (LTE Rel. 10 and beyond). To ensure that the actual mobile telecoms technologies will be able to come up with technology that could contend, you ought to make sure that brand new mobile technology are now being developed as well as created. This is actually the thinking at the rear of beginning the introduction of the brand new LTE-Advanced techniques, showing the actual technologies as well as building the actual LTE-Advanced requirements.


 While LTE's peak downlink speed is theoretically 300 Mbps, LTE-Advanced can ostensibly reach 1 Gbps but realistically would get only 100 Mbps in everyday use. LTE's uplink peak rates of 75 Mbps pale in comparison to LTE Advanced's 500 Mbps.
 Along with function beginning upon LTE-Advanced, numerous crucial specifications as well as crucial functions tend to be visiting lighting. While not set however within the specs, there are lots of higher level is designed for your brand new LTE-Advanced standards. These types of will have to become confirmed and far function continues to be carried out within the specs prior to they are almost all set. 

Presently a few of the primary heading is designed with regard to LTE-Advanced is visible beneath :-

1. Peak data rates : downlink - 1 Gbps; uplink - 500 Mbps.
2. Spectrum efficiency : 3 times greater than LTE.
3. Peak spectrum efficiency : downlink - 30 bps/Hz; uplink - 15 bps/Hz.
4. Spectrum use: the ability to support scalable bandwidth use and spectrum aggregation where non-contiguous spectrum needs to be used.
5. Latency : from Idle to Connected in less than 50 ms and then shorter than 5 ms one way for individual packet transmission.
6. Cell edge user throughput to be twice that of LTE.
7. Average user throughput to be 3 times that of LTE.
8. Mobility : Same as that in LTE
9. Compatibility : LTE-Advanced shall be capable of interworking with LTE and 3GPP legacy systems. 

LTE-Advanced would to be moving in numerous areas within 2013, along with suitable devices as well as gadgets growing together with this particular release.

Its full name is 3GPP Long Term Evolution for the Universal Mobile Telecommunications System, or 3GPP UMTS LTE for short. LTE (Long Term Evolution) is a wireless broadband technology designed to support roaming Internet access via cell phones and handheld devices.


Where the current generation of mobile telecommunication networks are collectively known as 3G, LTE is marketed as 4G.


Requirements :


LTE Specifications :



 LTE uses two different types of air interfaces (radio links), one for downlink (from tower to device), and one for uplink (from device to tower).For the downlink, LTE uses an OFDMA (orthogonal frequency division multiple access) air interface For the uplink (from device to tower), LTE uses the DFTS-OFDMA (discrete Fourier transform spread orthogonal frequency division multiple access) scheme of generating a SC-FDMA (single carrier frequency division multiple access) signal. 

The major difference between the OFDMA signal for downlink and the SC-FDMA signal for uplink is that it uses a discrete Fourier transform function on the data to convert it into a form that can be used to transmit.

  Both are 4G technologies designed to move data rather than voice. Both are IP networks based on OFDM (Orthogonal Frequency Division Multiplexing) technology.

   WiMax is based on a IEEE standard (802.16),Depending on the spectrum alloted for WiMax deployments and how the network is configured, this can mean a WiMax network is cheaper to build.

     WiMAX offers peak wireless data speeds of up to 60 Mbps on the downstream and 25 Mbps for sending data upstream.

    Long Term Evolution (LTE), can ferry data to you at download speeds of 100 Mbps and support upload speeds of 50 Mbps.

    That means you can download about two 5-minute MP3 files every second. Think about that. Sure, it would only take WiMAX about seven minutes to download a single 5-minute MP3 file, which is still fast, but it’s nowhere near the theoretical scale of LTE.

   LTE technology supports manufacturer’s rated peak download speeds of up to 150 megabits per second (Mbps) and upload speeds of up to 70 Mbps.

   Canadian operator TELUS has announced the plan to launch of LTE network 1st H 2012. Following field testing in 2011 and the completion of an RFP process currently underway, construction on TELUS' LTE network will begin in the latter half of 2011 in major urban markets across Canada. 

   Telus – the country’s third-largest operator – said that construction of the new network will begin in the latter half of 2011 in “major urban markets” across Canada. It will initially operate on

    Infrax Systems, Inc. (OTCBB: IFXY), a global provider of unified Smart Grid-related products and services for the Energy and Utility industries, today announced the availability of a new upgradeable WiMAX/LTE base station. This new base station option allows network operators and service providers to utilize the desirable 1.4-1.6 GHz frequencies. The addition of these new base stations will provide operators of rural broadband networks better range than the typical 2.5 or 3.5 GHz WiMAX. These new base stations also have the capability of being upgraded from WiMAX (802.16e) to Long Term Evolution (LTE) via firmware. These modular 4G base stations can even provide the ability to change to a different frequency by changing radio modules to provide more longevity of the platform and protect network operator's investments.

   The American Reinvestment and Recovery Act appropriated $7.2 billion for the Department of Agriculture’s Rural Utilities Service (RUS) and the Department of Commerce’s National

EPS to EPC

   A key feature of the EPS is the separation of the network entity that performs control-plane functionality (MME) from the network entity that performs bearer-plane functionality (SGW) with a well defined open interface between them (S11).


LTE S11: -

    An IP interface between MME and SGW! GTPv2 is the protocols used at the application

What is LTE?

    3GPP LTE (Long Term Evolution) is the name given to a project that aims to improve the
UMTS mobile phone and it is not a standard but it will result in the release 8 of UMTS
and it can be considered the real 3.9G & invited to join the 4G family.

Technical specifications:-


LTE PHY layer block diagram:-

    The IEEE Standards Association has given its seal of approval to the next generation WiMAX standard, dubbed 802.16m. The new standard supports a “wide range of data rates in multiple user environments” and has a theoretical maximum throughput of around 300Mbps.



     ” The standards group notes that 802.16m will provide the speed and performance necessary to support future advanced services and applications for next generation broadband mobile communications.”  said Dr. Roger Marks, Chairman of the 802.16 Working Group.

  WiMAX has four fundamental architectural components:


Base Station (BS) : 

      The BS is the node that logically connects wireless subscriber devices to operator networks. The BS maintains communications with subscriber devices and governs access to the operator networks. A BS consists of the infrastructure elements necessary to enable wireless communications, i.e., antennas, transceivers, and other electromagnetic wave transmitting equipment.

      BSs are typically fixed nodes, but they may also be used as part of mobile solutions , for example, a BS may be affixed to a vehicle to provide communications for nearby WiMAX devices. A BS also serves as a Master Relay-Base Station in the multi-hop relay topology .

WiMAX (Worldwide Interoperability for Microwave Access) ( 802.16 - 802.16e )


     It was defined by the WiMAX Forum is a telecommunication protocol that provided fixed and fully mobile broadband access (IEEE 802.16e ). WIMAX was developed to promote conformance and interoperability of the IEEE 802.16 standard (Wireless MAN). Meanwhile WIMAX Forum is the organization which dedicated to certifying the interoperability of broadband wireless access (BWA). WIMAX Forum will conduct the testing to ensure that different mobile broadband system from many manufactures work properly.

    

We will speak about the LTE Network Elements .
LTE network comprises of two main segments.
       1. LTE EUTRAN
       2. LTE Evolved Packet Core.


LTE EUTRAN: -


EUTRAN consists of eNB.

    EUTRAN is responsible for complete radio management in LTE. When UE comes up eNB is responsible for Radio Resource Management, i.e it shall do the radio bearer control, radio admission control, allocation of uplink and downlink to UE etc. When a packet from UE arrives to eNB, eNB shall compress the IP header and encrypt the data stream. It is also responsible for adding a GTP-U header to the payload and sending it to the SGW. Before the data is actually transmitted the control plane has to be established. eNB is responsible for choosing a MME using MME selection function.
    As the eNB is only entity on radio side, the whole QoS is taken care by it. It shall mark the packets in uplink, i.e Diffserv based on QCI, and also schedule the data.

    Other functionalities include scheduling and transmission of paging messages, broadcast messages, and bearer level rate enforcements based on UE-AMBR and MBR etc.

   The picture shows main network elements, interfaces and the protocols used in LTE.
The main interfaces in LTE are Uu, S1-MME, X2, S1-U, S11 and S5.

LTE Uu : -
    This is the air interface between UE and eNB. LTE layer 1 is dealt with later. RRC is the protocol that is used for communication between UE and eNB. Above RRC there is a NAS layer in UE. This NAS layer terminates at MME and eNB shall silently pass the NAS messages to MME.

LTE S1-MME: -

    eNB and MME communicate using this IP interface. S1-AP is application layer interface. The transport protocols used here is SCTP. (Stream control transmission protocol).