Senin, 31 Desember 2012

LOS Survey Process Tutorial



  Survey Process consists of five basic steps;
a) Prepare the Site documentation
b) verify the Site location
c) Finding Problems in-between the path
d) Path profile
e) Overall survey report.
Site Documents
a) Site location maps to be find with Location Land Mark.
b) If it is existing site means, get site information from other customer.
Collection of details of the proposed site;
a) Observe the Absolute Mean Sea Level, height of tower, heights of antenna and angles.
b) Take photographs of site, it used for verification in future.
c) Marking of tower center from minimum three reference points
transmitters and receivers Antennae frequencies.
e) Soil samples can be taken for laboratory testing. This will be useful for economical design of the tower.
Identification of critical points along the path
a) On the maps two sites are joined by a thin straight line.
b) Determine the height, width of all obstructions along the path and HASL at each point for all potential obstructions.
c) Visit every likely critical point to ascertain its height and check other parameters.
d) Determine the width of water bodies, other reflecting points falling along the route.
e) Take mirror tests if after calculations, it is found, that, it is feasible
Generating LOS path profile;
a) It can be manually or by computerized software.
b) Hop wise data required is given below.
About hop
AMSL of each site
Hop distance (If co-ordinates are fed to computer software, you get hop distance    and azimuth angles)
HASL of each obstruction and its height including near-end obstructions, Clearance criteria being adopted. Say  Cl=k 4/3 + 100% FFZ and OR Cl=k 2/3 + 60% FFZ
Frequency band of operation.
c) With the above parameters antenna heights in each direction of operation can be worked out and hence the tower height at each sight.
Generating LOS report
a) Site Data( Height, Angle , Azimuth)
b)Any Disturbance in Path
c)Photograph about Site for Future Identification.
Detailed Survey Report
a) Determine following parameters.
Transmitter power, Size and gain of antenna’s for main and diversity, transmission line losses, Receiver threshold  Signal to noise ratio, Fade Margin
b)The complete exercise can be worked out manually with the help of a calculator or different Software’s available for Path Loss Calculations.

VSWR Meter or Site Master Tutorial



Introduction
1) after completion of site installation to measure the efficiency of a site or to evaluate the performance of the site against different parameter like “hand-over, interference, call drop, call loss etc”, we perform VSWR measurement.
2) This is a single parameter to check to know how efficient your site is. Only VSWR can show how good your connector is made, how good your feeder cable is installed etc.
3) To measure the VSWR we used “Site Analyzer”. This is digital equipment which is not only gives the reading of VSWR but also tells where the fault is.
4) Site Analyzer is a multi function site management tool designed to help do much more than simply check broken cables or faulty antennas.

The Site Analyzer combines ease-of-use with powerful measurement and data analysis to help perform predictive maintenance.
PC software allows download to PC to analyze data for long-term assessment of system trends, problems, and performance.
We mostly used two types of site analyzer (master):
1. Bird Site Analyzer
2. Anritsu Site Analyzer
Bird Site Analyzer


 About Bird Site Analyzer:
1)You can see the site master which consist of a Display where the VSWR
reading is shown in graphical format, a key board is there to set the values
like frequency band, VSWR limit etc.
2)You will find few buttons like “Calibrate”, ”Config”, ”Mode”, “Marker”.
3) Calibrate is used to caliber the site analyzer before use.
Config is used to set the frequency band, VSWR limit etc.
4) Marker is used to set the marker for graph. We can set to show one marker only or more than one marker, up to 4 markers we can set.
5) Mode is used to select the operating mode e. g. measurement, fault location, power, etc.
6)Arrow button is used for up, down, left, right process whenever required.
7)On right hand side there is ON-OFF push button to turn ON and OFF to the site analyzer.
Calibrate Button:
Firstly you have to “calibrate” site analyzer before use. For this calibration tool is used. This tool has three ports, as
Open
 Short
 Load

 Calibration
To calibrate following process should be done:
1. Switch on the site analyzer
2. Push the calibrate button
3. Fit the open port of calibrate tool to the site analyzer. Push the open button (which you will find at the left hand site). After few second a message will appear “done”. Remove this open port and fit the short port.
4. Push the short button and wait for a while, a message will appear “done”. Remove the short port and fit the load port to the site analyzer.
5. Push the load button and wait for the message “done”.
6. After few second sites analyzer will show “Calibration FULL”.
7. Now site analyzer is ready to use.
Mode Button:
To measure the VSWR, to find the fault location, to set the scale of graph we used this button.
At the top of the site analyzer there is port to attach the cable who’s VSWR has to measure. For this purpose we can use Dummy or jumper cable.

 Process to Measure the VSWR:
1) firstly set the frequency band and VSWR limit.
2) Calibrate the site master.
Now by dummy or jumper cable, attach the cable who’s VSWR has to be measured.
3) Now push the mode button.
On the right hand side on display you will see “measure”, “fault location”, “scale” etc. Chose measure.
4) A graph will appear, with actual value of VSWR. On the bottom you can also see the value of VSWR in the digital format. The marker will show the value. By left, right, up, down arrow you can know the value of VSWR on different distance.
5) For locating fault distance push the mode button and then fault location you will get a graph which will show the distance of maximum loss of the signal
Anritsu Site Analyzer:
Anritsu is the another site master which can also use for VSWR measurement.
The operation of Anritsu is also same as Bird site analyzer.  With the help of Anritsu we can also save reading. The whole process as calibrate, config, measurement are
same.

Minggu, 30 Desember 2012

Microwave Link Traffic Tutorial



a) Microwave Link connects two cellular network sites.
b) It carries two types of traffic: Voice and Data.
C) Commonly each BTS site has one E1 (2 Mbps) of transmission capacity.
d) PDH or SDH are the two standards for traffic capacity over Microwave Link in terms of E1. 2 x 2 (2E1), 4 x 2 (4E1), 8 x 2 (8E1), 16x 2 (16E1), STM1 etc.
E) PDH Transmission rates
E1-2 Mbps
E2-8 Mbps
E3-34 Mbps
E4-140 Mbps
E5-565 Mbps
f) SDH Transmission rates
STM-1-155.52 Mbps
STM-4-622.08 Mbps
STM-16-2488.32 Mbps
STM-64-9953.28 Mbps
Figure : Microwave Link Traffic
PCM Planning;
1) PCM planning is basically Capacity, Equipment & Network Topology planning.
2) Information required for PCM planning
a) Permit blocking possibility at various interfaces
b) Location of the equipment in the site and their configurations.
c) Current traffic load in the site.
d) About the LOS between the sites.
3) Capacity of a microwave link depends on the number of E1 (2Mbps) data carried from one site to another.
Topology Planning;
For cities < 4 sites
all hops shall be in a star topology employing 16×2 radios in 1+0 configuration.
Figure : Topology Planning
For cities >5 & <8 br="br" sites="sites">All hops shall be in a star topology employing 16×2 radios in 1+0 configuration.
Figure : Topology Planning
For cities >9 till 14 sites
PDH rings are considered for cities > 9 till 14 sites.
Figure : Topology Planning
For cities >15 till 28 sites
SDH rings are considered for cities > 15 to 28 sites.
Figure : Topology Planning
For cities > 29 to 6 sites
SDH rings are considered for cities > 29to 56 sites.
Figure : Topology Planning
For cities > 57 to 110 sites
Figure : Topology Planning
BoM
1) Inputs for Transmission Planning;
Count of new town and existing towns sites and the subscribers in each site.
From the above data, the number of BSCs required is to be calculated.
The final capacity for each route or link
2)Nominal Transmission Plan
Based on the above inputs, the planner should prepare the nominal connectivity plan by plotting all the new sites on the tool and BSCs can be fixed.
After nominal connectivity plan it is known how many 7GHz/15GHz/18GHz/23GHz links are required.
Based on the above the MW requirement can be given as BoM
Equipment Requirement;
1) Indoor/Outdoor Unit Estimation
Generally one BTS gives one E1.
The microwave hop would be about 20% over the number of BTS, for upgrade, last mile connectivity.
IDU should be 30% more than no. of MW hops.
2) Metro hub Estimation
Each Metro hub can cater for one 16E1 loop.
For dimensioning assume 6 – 8 BTS per Metro hub as some BTS may have more than 1E1. The Metro hub is configured with 1 FIU and 3 RRI cards.
In case of a mixed Microwave network and if the ring origination/termination hops at the BSC/hub site are non-Nokia, then the Metro hub configuration would be 3 FIU + 3 RRI.
3)  Each hop requires one or more antennas (with cable and accessories) as per diversity/protection configuration.

LOS Survey Process Tutorial



 Survey Process consists of five basic steps;
a) Prepare the Site documentation
b) verify the Site location
c) Finding Problems in-between the path
d) Path profile
e) Overall survey report.
Site Documents
a) Site location maps to be find with Location Land Mark.
b) If it is existing site means, get site information from other customer.
Collection of details of the proposed site;
a) Observe the Absolute Mean Sea Level, height of tower, heights of antenna and angles.
b) Take photographs of site, it used for verification in future.
c) Marking of tower center from minimum three reference points
transmitters and receivers Antennae frequencies.
e) Soil samples can be taken for laboratory testing. This will be useful for economical design of the tower.
Identification of critical points along the path
a) On the maps two sites are joined by a thin straight line.
b) Determine the height, width of all obstructions along the path and HASL at each point for all potential obstructions.
c) Visit every likely critical point to ascertain its height and check other parameters.
d) Determine the width of water bodies, other reflecting points falling along the route.
e) Take mirror tests if after calculations, it is found, that, it is feasible
Generating LOS path profile;
a) It can be manually or by computerized software.
b) Hop wise data required is given below.
About hop
AMSL of each site
Hop distance (If co-ordinates are fed to computer software, you get hop distance    and azimuth angles)
HASL of each obstruction and its height including near-end obstructions, Clearance criteria being adopted. Say  Cl=k 4/3 + 100% FFZ and OR Cl=k 2/3 + 60% FFZ
Frequency band of operation.
c) With the above parameters antenna heights in each direction of operation can be worked out and hence the tower height at each sight.
Generating LOS report
a) Site Data( Height, Angle , Azimuth)
b)Any Disturbance in Path
c)Photograph about Site for Future Identification.
Detailed Survey Report
a) Determine following parameters.
Transmitter power, Size and gain of antenna’s for main and diversity, transmission line losses, Receiver threshold  Signal to noise ratio, Fade Margin
b)The complete exercise can be worked out manually with the help of a calculator or different Software’s available for Path Loss Calculations.

TutoriaI of IP over Optical Networks



Optical Networks
optic
Fiber
•Provides the physical transport medium
Optical networks: Create the pipes
•WDM: Fast pipes for voice/data
•Optical amplification: Long pipes
IP Routers, ATM switches, SDH equipment: Fill the pipes
Operations Support System (OSS)
•Manage all aspects of the network
 
 
 
Evolution of Transmission Technology
•1st Generation: Copper is transmission medium
•2nd Generation: Optical Fiber (late 80s)
4Higher data rates; longer link lengths
•Dense Wavelength-Division Multiplexing (DWDM, 1994)
4Fiber exhaust forces DWDM
4Erbium-doped fiber amplifiers (EDFAs) lower DWDM transmission cost
•3rd Generation: Intelligent optical networking (1999)
4Routing and signaling for optical paths

Dense Wavelength-Division Multiplexing (DWDM)
 
 
DWDM Evolution
 
•Faster (higher speed per wave),
440 Gb/s on the horizon
•Thicker (more waves),
4160 waves possible today
•Longer (link lengths before regeneration)
4A few thousand km possible today
•160 waves at 10 Gb/s = 1.6 Tb/s
425 million simultaneous phone calls
45 million books per minute
 
IP over ATM
ATM over SONET
IP over ATM over SONET
 
Optical Pass-Through (Routing)
Intelligent Optical Networking
Optics is not merely a transmission technology
•Optics provides a flexible layer upon which to deliver network service
DWDM provides enormous link capacities
•DWDM: Physical layer of Intelligent Optical Network
Routing and signaling of optical paths
•Provides significant economies over conventional network architectures
•Enables revolutionary new services
42.5 Gb/s path from Bangalore to Boston, on demand!
 
SONET over Optical Layer
IP over SONET over Optical Layer
IP over Optical Layer
 
IP over Intelligent Optical Networks
§Establish high-speed optical layer connections (lightpaths)
§IP routers connected through lightpaths rather than fiber
§Switching (WDM crossconnects) add flexibility to the optical layer
•Flexible, potentially rich, topology at IP layer

Ericsson APG 40 Commands Tutorial



APG 40Basic Commands
Basic AP Information
prcstate          Print whether the AP node is active or passive.
hostname       Print the computer (host) name of the AP node.
swrprod          Print a summary of installed software.
swrprint           Print a list of installed software (use the ‘-l’ parameter for a detailed list)
date /t  Print the current system date
time /t  Print the current system time
sfcstate           Print the current soft function change state of the node.
fchstart -V       Print the current hard function change state of the node.
echo %USERDOMAIN%\%USERNAME%       Print the username that you are currently
logged on as.
AP Cluster and Node Status
alist  List alarms
cluster node    Print the status of cluster nodes
cluster group  Print the status of the cluster groups
cluster res       Print the status of the cluster resources
cluster res | find /v “Online”   Print the status of the cluster resources that are not Online
cluster net       Print the status of the cluster networks
cluster netint   Print the status of the cluster network interfaces
net start          List started Windows NT services
pstat | find “pid:”      List processes
Network Configuration and Status
ipconfig /all     Display full IP configuration information.
route print       Display IP interface list and IP routing table.
netstat -a        Display all IP connections and listening ports.
cluster netint /prop   List the properties of all Cluster network interfaces.
cluster netint /prop | find “Address”   List the IP addresses of all Cluster network interfaces.
netstat -e -s    Display current ethernet and network protocol statistics
arp -a  Display the IP-to-Physical address translation tables used by address
resolution protocol.
Hardware Status
fcc_amtest own         Test the AM board of the own AP node.
fcc_amtest other       Test the AM board of the other AP node.
Note: These commands need to be executed from the
directory ‘C:\Program Files\FORCE\AM_Services’ .

AP-CP Communication (AP commands)
cpdlist –l         List defined Alphanumeric Devices (ADs) (printout categiroes)
cpdlist –a        (userID and remote host of the device)
cpdlist -p         (default log and program directories)
cuals  List the mapping between APG40 groups and AXE users for determining AXE
command rights.
bupprint -a      Print all parameters that are used for backup generation handling and
command log handling that are connected with AXE reload.

Jumat, 21 Desember 2012

Distributed Antenna Systems Deliver LTE Success




Mobile networks originally were designed to provide outdoor service. While many users receive adequate coverage inside of buildings when using 2G or 3G services, the picture changes with 4G (LTE) service. Distributed antenna systems (DAS) can deliver the in-building coverage and capacity needed to serve LTE users.

In-Building Challenges

Coverage and capacity are the two fundamental challenges for enterprises seeking to deliver high-performance mobile services within their offices and plants. LTE promises multiple megabytes of downlink data per user, and it is impossible for a macro network alone to provide this level of capacity. Effective LTE service will require basestation antennas to be moved much closer to end users to serve fewer users per antenna. DAS enables this type of architecture.
It will also be necessary to move basestation antennas inside buildings to provide the required coverage for LTE users. Many frequencies being used for 4G services attenuate much more quickly than 3G or 2G frequencies, making it more difficult for them to penetrate building walls.
In seeking a solution for in-building coverage and capacity, there are three key considerations:
  • Ease/cost of deployment: The network infrastructure must be simple and cost-effective to deploy, or else service providers won’t install it or the speed of network rollout will be unacceptable to users. Existing buildings are particularly problematic since there is a lot of infrastructure to work around, and such installations can disrupt normal business operations.
  • Scalability: The infrastructure should easily scale to cover new areas, support higher capacity, and adapt to future implementations of wireless standards such as LTE-Advanced and to shifts from single-input single-output (SISO) to multiple-input multiple-output (MIMO) operation. The in-building wireless solution should, like a fiber optic network, handle whatever applications will be required today and in the future.
  • Flexibility: The solution should support multiple mobile operator services. While enterprises may have a corporate purchase agreement with a particular mobile operator, the in-building system must provide service for contractors, visitors, and other people in the building who use other services. The solution should also accommodate network changes as spectrum is acquired or divested.

Potential Solutions For Indoor Coverage
To meet the basic coverage and capacity requirements for in-building coverage, the enterprise or its mobile operators must deploy systems that bring the cellular signal inside the building. There are two basic approaches:
  • Deploy new, small mobile basestations (femto, pico, and microcells) to radiate signals from their locations
  • Deploy multi-band, multi-protocol distributed antenna systems to propagate signals from a single radio source

1. Single-service small basestations can be deployed in enterprise offices, fixing a specific service and capacity to a location.1. Single-service small basestations can be deployed in enterprise offices, fixing a specific service and capacity to a location.
Femto, pico, and micro cells are becoming important tools for improving coverage and capacity, and there is a lot of buzz about using them to solve enterprise mobile challenges. Service providers are using pico or micro cells on a limited basis to provide coverage and capacity inside public structures or enterprises, and they are now beginning to offer femto cells for coverage in residences, small offices, and other buildings as small as 1500 square meters in size (Fig. 1).
These devices provide both coverage and capacity, and many of the smaller products are easy to install and require a minimum of space. With each cell you add, you get more coverage and more capacity. But there are some disadvantages as well:
  • Each small basestation must be managed, so using these cells as the only solution in a building that could require dozens or hundreds of units, which will create vast new demands on service provider and user resources. With a proliferation of pico and femto cells, service providers may not want to shoulder the burden of managing the equipment and the ongoing system engineering requirements.
  • Each small cell provides one or two frequency bands, so if a building needs to support service from several mobile operators, it will need more than one set of equipment in each small cell.
  • Each small cell has a fixed amount of capacity tied to the coverage area of the cell. Thus, traffic engineering to meet peak usage demands is critical.
  • Service providers have a limited amount of frequency spectrum at their disposal. Service providers manage this problem with large cells by simply alternating frequencies so no two cells using the same frequency will overlap. But since each small cell in an adjacent area must use a different frequency, small cells multiply the chances for interference and make it difficult to manage available spectrum efficiently.

Distributed antenna systems address the potential issues that may arise when using a small basestation as the sole solution to coverage and capacity problems. A DAS works with an available signal source (either an antenna/repeater that captures the signal from the service provider’s macro network or directly from a small cell or basestation) and then uniformly distributes that signal and channel capacity throughout a given area via a series of amplifiers and antennas. A DAS can deliver signals from one or multiple service providers, depending on the number of signal sources to which it is connected.
There are several advantages of using a DAS in conjunction with basestations to create a small-cell architecture:
  • A DAS extends the signal from one or more basestations, so service providers or enterprises can use them to provide service to a large area while reducing the number of basestations required, maximizing the use of existing radio resources.
  • Compared with small basestations, distributed antenna systems are quite reliable, easy to manage, and inherently scalable.
  • Distributed antenna systems are relatively inexpensive and easy to deploy.

There are three basic types of distributed antenna systems on the market today: passive, active, and hybrid. Each type of system has specific strengths and weaknesses when it comes to providing in-building coverage for 4G networks.
Passive Systems
Passive systems use thick coaxial cable (0.5 to 1 in. in diameter) to distribute the wireless signal. The main distribution unit is connected to the signal source, and then the unit drives the signal over the coaxial cable. The coaxial cable used to distribute radio signals is inherently capable of supporting multiple carrier frequencies. While passive systems are thereby viewed as simpler, one-stop solutions for indoor wireless coverage, there is also a great risk of signal interference, and multiple bands may “mix” and produce noise on the network.
In a passive system, the signal degrades with the length of the cable in any particular run. As a result, passive systems are not well suited to large facilities with long or complex cable runs or to facilities that require high call capacity or high signal strength. Even in a relatively small deployment with as few as 16 antennas, users may need to stand very close to the antenna to get a good signal. Signal quality degrades the farther the cable is from the RF source.
Passive systems do not offer end-to-end monitoring and management. The signal is simply being pushed out over copper cabling, so service providers and building owners never know if a particular antenna has failed until users start complaining.
Finally, passive systems are more difficult and expensive to install, because their heavy and rigid cabling requires special expertise and often special cable raceways or hangers. Since the cabling is not as flexible, it is also more difficult to deploy in tight spaces.
Active Systems
2. Multi-operator distributed antenna systems can be deployed in an enterprise office to simulcast aggregate capacity throughout the network.2. Multi-operator distributed antenna systems can be deployed in an enterprise office to simulcast aggregate capacity throughout the network.
Active distributed antenna systems use managed hubs and standard building cabling (i.e., single-mode or multi-mode fiber and CATV cabling), much like an Ethernet local-area network (LAN). In an active DAS, the main hub is deployed in the building’s equipment room, and it distributes the wireless signal from a local or remote basestation through a series of expansion hubs, remote amplifier units (RAUs), and antennas (Fig. 2). The DAS aggregates all capacity and simulcasts the signal to each antenna location. Two antennas may be used when the systems support MIMO applications.
Because the signal is amplified at the RAUs, there is no end-to-end signal loss. Active distributed antenna systems deliver strong and consistent signals at every antenna, no matter how far away they are from the signal source and main hub, making them easy to design and the user experience consistent. In the largest airports and multi-facility deployments such as major hotels on the Las Vegas strip, some active distributed antenna systems extend for miles. Since every antenna has predictable signal strength and coverage, it is far easier to plan the antenna placement in an active system.
The distributed hub architecture of an active system mirrors the design of Ethernet LANs. It scales easily through the addition of new antennas and hubs, and the hub electronics can be upgraded to support new services as they come online. This leaves the most expensive part of the system, the cabling and antenna plant, untouched. Active systems usually support simple network management protocol (SNMP) alarms as well, so a company’s IT staff can monitor the status of all remote antennas in the network using the same network management tools used for the LAN.
Active DAS can be less expensive and are less disruptive to deploy because their standard cabling is inexpensive, and the job can be handled by IT cabling contractors or electricians rather than specialized technicians. Standard cabling can be run across suspended ceilings and in tight spaces like conduit just as easily as LAN cabling. In many cases, an active system can use existing, unused fiber that runs up a multistory building’s utility riser to link a main hub with expansion hubs and then use new CATV cabling to connect each expansion hub to its RAUs and antennas. While multiple sets of electronics may be required to support all service providers (depending on the service providers’ requirements), the cost of cable runs is a larger factor in the overall price of a system in all but the smallest facilities. Active distributed antenna systems minimize this cost.
Hybrid Systems
Hybrid distributed antenna systems combine attributes of both passive and active systems. They use fiber-optic cabling to carry the signal from the basestation up a building riser to remote units in intermediate distribution frame (IDF) closets and then use thick 0.5-in. coaxial cabling from the remotes to carry the signal horizontally across each floor of the building. In the case of LTE, this coaxial cable antenna network must be doubled if MIMO support is required.
Hybrid systems partially alleviate the problem with signal loss and variable signal strength at each antenna because there is far less signal loss in the vertical portion of the system. However, these systems have the same signal loss issues in the horizontal cable runs to individual antennas as a passive system. Overall, output at any given antenna will be higher, but there will still be variability in signal strength and coverage at an antenna, depending on its distance from the fiber-optic portion of the system. And, these solutions are still vulnerable to the RF interference issues as signals combine in their native RF waveforms.
In the same way, hybrid systems only partially solve the management and cost challenges of DAS deployment. They offer management between the basestation and the remote units at each floor, but not between those remotes and individual antennas. And while building owners save partly on the cost of deployment on the fiber portion of a hybrid DAS, they encounter the same cost and disruption issues when installing heavy coaxial cabling and antennas on each floor.
As we move into the 4G mobile service era, in-building mobile network solutions will be crucial to providing strong, clear, high-bandwidth connectivity for all users. Service providers and building owners are already deploying DAS in large buildings, stadiums, airports, hotels, hospitals, and other facilities. As 4G services hit a growth curve, we will see more DAS deployed to provide the needed coverage and capacity.

Distributed antenna system advantages and disadvantages


Distributed Antenna System DAS

- overview, summary, tutorial about the DAS, Distributed Antenna Systems technology used for gaining better coverage and using a lower power.

The concept of a Distributed Antenna System, DAS has many advantages in some applications. A Distributed antenna system, DAS is a network of antennas spaced apart from each other, but connected to a common source. In this way the DAS is able to provide wireless or radio coverage within a given area.
The idea of a distributed antenna system is being adopted increasingly as it enables a number of advantages to be gained. However this is at the cost of a larger more complicated system. Nevertheless, distributed antenna systems are being used in a variety of areas to enable the right coverage to be gained for several applications.
Although the concept of distributed antenna systems has been known about for many years, it is with the increased deployment of wireless systems within buildings and other difficult coverage areas that the idea of distributed antenna systems has come to the fore.


Advantages of using a distributed antenna system
  • Better defined coverage
  • Fewer coverage holes
  • Same coverage using a lower overall power
  • Lowers health risk as a result of using lower overall power levels
  • Individual antennas do not need to be as high as a single antenna for the equivalent coverage
Disadvantages of using a distributed antenna system
  • Higher cost as a result of additional infrastructure required
  • Possible greater visual impact in some applications as a result of greater number of antennas, although they are likely to be much lower in height.

Basic concept of a distributed antenna system

The basic idea behind the distributed antenna system is to utilise several different antennas over the required coverage area. Using this approach the overall power required is less because these more localised antennas can be placed more effectively for a small area, rather than having a single, larger antenna that is a compromise for the wider coverage needed. By adopting a distributed antenna system approach, this helps overcome the shadowing and penetration losses because a line of sight link is available more frequently. As a result the levels of absorption are lower and this means the overall power levels can be reduced.

Selasa, 18 Desember 2012

LTE Protocols & Specifications Tutorial



In Long Term Evolution architecture consists of
1) Mobility Management Entity
2) Serving Gateway
3)  Packet Data Network Gateway
E-UTRAN consists of EnodeB
In LTE Technology ,Data rates is more and Larger Bandwidth and packet-optimized system.
Protocol structure of control plane in between Mobile Equipement and & Mobility Management Entity is shown below;
Figure : user plane between UE and MME
protocol structure in between Mobile Equipement & Packet Data Network Gateway user plane;
GTP-U Protocols user data between eNodeB and the Serving Gateway and also between the Serving Gateway and thePacket Data Network Gateway in the backbone network.
Figure : user plane between the UE and PGW
Figure says that control & user plane protocol stack of the X2 interface;
Figure : control and user plane protocol stack of the X2 interface

Single Radio Voice Call Continuity (SRVCC)




A VoLTE voice service continuity solution, mainly in order to solve problem of how to ensure that the voice call continuity when a single radio UE moves between the LTE / Pre-LTE network and 2G/3G CS network, i.e. to ensure a single RF UE smooth switching between IMS VoIP voice control and CS domain voice.

The simplest use model can be illustrated as in < Case 1 > of the following figure showing the SRVCC between LTE and UMTS (The detailed mechanism would vary depending on what kind of legacy technology is involved). A little bit complicated use-model can be illustrated as in < Case 2 >. In < Case 2 >, user is doing VoIP while he is using another packet transaction (e.g, email, browsing etc). In this case, the radio bearer on WCDMA side should be a multiple Radio Bearer (CS + PS). There may be many different type of use model as well.
Vo Lte


Vo Lte


Minggu, 16 Desember 2012

Sector Swapping Drive Test



Types of Cable swapping
1)Complete Cross feeder(GSM or DCS)
2)Composite Swap(GSM or DCS)
3)GSM or DCS cable Swap
4)Wrong Antenna installation
1)Complete Cross feeder(GSM or DCS)
•Analysis
           Completely crossed feeder cable of two sectors.
           coverage area of the two adjacent  cells or swapped.
•Problem
            Frequent INTRA Cell handover
            Handover failure
            Sometimes call drops
Figure : Complete Cross feeder(GSM or DCS)
2)Composite Swap(GSM or DCS)
• Analysis
          Feeder Cable  of two or three sectors or partially swapped.
         Tx  feeder Cable is correct Rx feeder cable is swapped.
         Tx feeder Cable Swapped Rx came cable are correct.
•Problem
         fluctuation in Rx level continually when we near to site.
Figure : Composite Swap(GSM or DCS)
 3)GSM-DCS Cable Swap
•Analysis
          GSM feeders or connected to DCS
• Problem    
        Frequent INTRA Cell handover.
        Handover failure.
          Sometimes call drops.
Figure : GSM-DCS Cable Swap
4)Wrong Antenna installation
•Analysis
          Sub case of composite Swap and mostly in complex  site.
          Wrong installation in inside the cabinet.
          Knowledge of TRX configuration will helpful to solve this problem.
•   Problem
             Lot of handover failure.
           Call drops due to missing neighbors.
Figure : Wrong Antenna installation
Sector/Cable swap
Problem Due to Swap
Figure;1
figure : Problem Due to Swap
Figure 2;
Figure : Problem Due to Swap
Reason for Sector Swap and Wrong installation;
              Due to very huge and fast deployment sector swap and  wrong installation is common.
The main reason  is behind in hardware installation.
Antenna and feeders  are installed at one time and  BTS and other hardware  are installed an power up at other  time.
Here the responsibility of acceptance team comes who need  to verify these  type of problems very carefully in field.
 Case Study I ;
Pre-Drive
There was a sector swap between sector 2 and sector  3 in 900 band.
This can be categorized into  “Complete Cross Feeder” .
But  here No swap was found in complete cable trace from BTS to top of Antenna.
But sector was found inside the Cabinet cabling between TRx and Duplexer.
It Cause result:  Handover Failure
Figure : Pre drive

Post Drive
Swap was removed by the help of BSS engineer and Rigger
Figure : Post Drive
Case study II
 Pre-Drive
In sector 2  GSM Feeder cable is connected to DCS duplexer and DCS  Feeder Cable is connected to BTS Duplexer.This can be categorized into GSM/DCS  Cable Swap.In this type  there is no clear  identification, But drive tester may observed .ProblemFrequent  INTRA Handovers.
Handover failures.
Some times call drop due to Low Rx level  even near  to  BTS.
Figure : Pre Drive

 Post-Drive
Figure : Post Drive

 Example for Swapping
Figure : Examples of Swappping

EVDO Drive Test Procedure



EVDO(Evolution Data Optimized)
  • Wireless data Optimized
  • standarized by 3GPP2.
  • Evolution of CDMA 2000 (1*RTT).
  • EV DO Channel Bamdwidth of 1.25 Khz.
  • Back end Network is enterly Packet Based.
  • Standard revision  -Rev 0,-Rev A,-  Rev B
  • Uses Adaptive Modulation.
  • Offer Bandwidth efficecy for Data Traffic 3-4 Times greater than voice centric standard
  • Same range as a cell Phone Signal..
CDMA EVDO DRIVE IN TEMS
Procedure  for Doing Drive Test in EVDO by Test Software
Step 1;
Figure : EVDO Drive Test Procedure
Step 2;
Figure : EVDO Drive Test Procedure
Step 3;We can see  EVDO Throughput

Figure : EVDO Drive Test Procedure

RF Survey Tutorial



RF Survey  is Collection of data s from the site or in  Field    for installing a new site .Just checking the Practically  of Cell Site ,for making determination for Coverage Region of Cell Site & for Deciding the Link/Connectivity with the another  Cell Site.
Need for Wireless Site Survey
RF Survey is used to find the Problems in the Site .Because ,In wireless network many issues  arise day by day ,which can prevent the signals from reaching all parts .Examples ;By  multipath Distortion ,Near Far end Problem.In order to avoid the problem ,we are doing RF Survey .RF Survey  helps us to find the  place where multipath distortion can occur,any interference.By doing RF Survey ,we can eliminate the problem .
Types of RF survey
1) RND (Radio Network Design) survey.
2)TND (Transmission Network Design) survey.
1) RND (Radio Network Design) survey.
              It  is Used for Deciding the Coverage for  a new cell Site ,we need to see some criteria in cell site
1.Site Location2. Orientation or Azimuth of GSM Antenna.3. Height of GSM Antenna.4. Tilt of the GSM AntennaTypes of RND Survey:-

1)Coverage Site Survey;It is done  for  New Site or Existing site
2)Capacity Site Survey;It is done in  Existing site  ,Just check the Load of the site,check the Population in that  region
Coverage Site Survey;
Step By Step Process:-
1)By using GPS find the Location of the Site according to our Data
2)Check the Population of the Region ,Disturbance  or Not.and also check the Nominal Point .
3)If  Nominal is Not visible means just inform to  Project Co-ordinator & Check another Nominal Point.
4)If visible means  than Decide the   Site Location.
5) Collecting the data in site  throughout  all 360 Direction.
6)Coverage Area Can be Decided by ;
         Frequency Band
Neighbor Cell Site Distance
AMSL Variation
Population Density of Area
7) Note  all the data or  Information in Note Pad
Capacity Site (off Loading) Survey
1)By using GPS find the Location of the Site according to our Data
2)Check the Population of the Region ,Disturbance  or Not.and also check the Nominal Point .
3)If  Nominal is Not visible means just inform to  Project Co-ordinator & Check another Nominal Point.
4)If visible means  than Decide the   Site Location.location must not be more than 50 m,
5)If you cannot  visible means  in other site means ,inform to your co ordinator 6) After that decide the orientation ,according to Population.If it is Conjunction means ,where required to OFF LOAD the sector.
7)Decide the Height of Tower, by Checking the Height of Microwave Antenna & GSM Antenna.

Microwave Antennae Installation Tutorial



 
Microwaves;
Microwaves are electromagnetic waves with frequencies ranging from 300 MHz to 300 GHz.
Frequency bands used for Microwave transmission are 7G/8G/11G/13G/15G/18G/23G/26G/32G/38G.
It is used for transmitting and receives the signals in point-to-point communication systems.
Figure : Microwave
Microwave Link;
Microwave links is used for transmitting and Receive high data capacity .Microwave is used instead of transmission lines.
Figure : Microwave Link
Microwave Link Installation consideration;
1) Line Of Sight
2) Fresnel Zone
3) Antenna height
4) Frequency band
5) Capacity
6) Modulation
7) Polarization
8) Antenna size
9) Trans and receive level
10) Orientation angle
11) Antenna alignment
12) Installation tools
13) Installation Material
Figure : Microwave Link Installation
Calculation of antenna diameter;
Calculation shows that 90 cm antenna is required.
Figure : Antennae Diameter
Approximately Hop Distances;
Figure : Hop Distance
Microwave Communication System components;
IDU, RF Unit, ODU, Microwave Antenna, IF cable, Pole for instillation.
Figure : Components used for Instillation

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