Concept of In-Building SolutionsHi-speed wireless connectivity in workplace, airports, hotels, conventioncenters, hospitals etc is becoming more prevalent. It provides today’sbusiness executives equipped with laptops, wireless LAN, mobile sets withseamless wireless email and Internet service. The macro coverage from outdoor site is not sufficient to meet this ever-growing demand, and there willbe multi cell issue (see the picture) so deploy a robust in-building wirelesssolution for creating a competitive niche and better user experience... For example, a building may not receive adequatemobile coverage from outdoor cell sites. This isbecause in most cases the signals present outsidethe building are unable to penetrate the buildingmaterial, thus resulting in poor coverage. A typicalproblem in high rises is the problem of interference.Crowded areas like malls, airports, large commercialcomplexes need a dedicated system to handle thecapacity requirements for the large number of callsat such locations. Further with 3G quickly gettingpopularity amongst these above mentioned interfeerence from distant bastations is ademographies, network strength, quality and problemcapacity etc are becoming a cause of major concern 3
Why In-building Coverage is Important?There are many reasons for the mobile operator for providing a dedicated IB coverage But mainly these are two Technical Commercial•lack of coverage •Some countries more than 50% traffic•Improvement of service quality from in building•Need for more capacity •Indoor Solutions Can Make a Great•Need for higher _ speed data rate Business Case •Maximize the revenue of the operator
The Indoor Planning ProcedureIBS SurveyIBS Planning & designingIBS ImplementationIBS Quality TestIBS O & M
For providing a good IB Solution first we have to do a proper survey
•Walk test tool(Net monitor, Nemo ,TEMS etc.)•Measurement tape•Still Camera•G.P.S
G.P.SThe Global Positioning System (GPS) is a space-based globalnavigation satellite system (GNSS) that provides reliable location andtime information in all weather and at all times and anywhere on ornear the Earth when and where there is an unobstructed line of sight tofour or more GPS satellites.
CameraCamera is using to take the pictures ofBTS location, Microwave pole location,Shafts and Line of Site etc.
Measuring TapeThe use of this in In Building survey are to measure the BTS location.Microwave pole length. Distance between earth point to Equipment roomIF cable length etc..
Survey ProcedureWalk testCheck the BCCH ,RXL,RXQ,CID of the all cells which are present in the buildingCollect the Auto card design of the BuildingCheck the BTS& Microwave pole locationCheck the cable shaft for running the Back bone cableTake the Photographs of BuildingTake the Photographs of BTS ,cable shaft and microwave pole locationCheck the Electrical supply /PointCheck the Earth pointMeasure the Earth cable lengthMeasure the power cable lengthMeasure the IF cable lengthTake the contact details of the building contact person
•Coverage planning •Capacity planning• Antenna marking on floor plan •Calculate the expected foot fall in•Make trunking Diagram side building•Calculate The EIRP of each •Calculate the total erlangantenna required•Calculate the BOM •As per erlang calculation•The ideal distance between two calculate the number of TRXantenna is 20m •Then plan the number of sector•All passive materials like •Normal commercial building perspliter,coupler,cable antenna are subscriber erlang is 20MEshould be support from 850 MHz •High capacity site like Airport perto 2500 MHz band subscriber erlang is 33ME•Tool used for IBS Design - IB •In Sector planning try to avoidWave multi sectors in single floor
Antenna marking on floor plan 20m Indoor coverage radius and area vs. design level from Omni antennaTo provide ‘full coverage’, antennas need to be placed with a certain coverage over lap
Placing the Indoor Antennas•Place the hot-spot antennas and maximize data performance.In this case of a shopping mall, the hot-spots for data and voice are typically thefood court, internet cafes and sitting areas•Place the ‘cost-cutting’ antennas.After the hot-spot antennas are placed you must placeall the antennas that will maximize the coverage per antenna•Isolate the building.Proper planning of an antenna at the entrance area and hand over zoneswill isolate the building from even very close out door sites.•Fill in the gaps.The last placement of antennas will be ‘filling the gaps’ between theantennas just placed This will help to provide maximum coverage
Indoor Radio planning tool IB Wave _ The most popular in door RF planning tooliBwave Solutions is a telecom radio planning software provider that developssolutions for the in-building wireless industry. iBwave is best known for itssoftware iBwave Design, mostly used by telecom operators, system integratorsand equipment vendors. iBwave is a Canadian-based company that wasfounded in 2003 and is headquartered in Montreal.A privately-held company, iBwave focuses on integrated solutions to automateand standardize the design of wireless communications inside buildings andinfrastructures.In 2010,
Traffic dimensioningErlang _The Traffic MeasurementAn Erlang is a unit of telecommunications traffic measurement.One Erlang is the continuous use of one voice channel. In call minutes, one Erlang is 60 min/h,1440 call min/24 h. In practice, when doing mobile capacity calculations, an Erlang is used todescribe the total traffic volume of 1 h, for a specific cell.Call Blocking, Grade of ServiceThe blocking rate (grade of service or GOS) is defined as the percentage of calls thatare rejected due to lack of channels. If the users makes 100 calls, and one call is rejecteddue to lack of channels (capacity) the blocking rate is 1 in 100, or 1%. This is referred toas 1% GOS. Operators might differentiate the GOS target for different indoor solutions,with a strict GOS of 0.5% in an office building but allowing a GOS of 2% in shoppingThe Erlang B TableProvided that the calls are Erlang-distributed, you can use the Erlang B formula to calculatethe required number of channels at a given load rate, and a given grade of service.
Erlang ExampleIf a group of 20 users makes 60 calls in 1 h, and each call had an averageduration of 3 min,then we can calculate the traffic in Erlangs:total minutes of traffic in 1 h = duration × number of callstotal minutes of traffic in 1 h = 3 × 60total minutes of traffic in 1 h = 180 minThe Erlangs are defined as traffic (minutes) per hour:Erlangs = 180/60 = 3EKnowing the number of users (20), we can calculate the load per user:user load = total load/number of usersuser load = 3/20 = 0.150 E = 150mE per userThen, if we have the same type of users inside a building with 350 mobileusers, we can calculate what capacity we need:total load = number of users × load per usertotal load = 350 × 150mE= 52.5E
Typical user load in ErlangUser type Traffic load per userExtreme user : 200 mEHeavy user :100 mENormal office user :50 mEPrivate user :20 mE
Special design considerationsMost of the design methods and considerations are the same for all building. But the below mentionedare some of the points we need to address, in addition to all the standard RF considerations. • Make sure you prepare for more capacity or sectors for future upgrades. • Make sure you cover the executive floor 100%. • Is there a need for elevator coverage? • Are there special installation challenges (e.g. fire proofing)? • Pay attention to the service rooms or areas (e.g. IT server rooms). • Are there special EMR concerns (like in a hospital)? • What type of services might be needed in the future – 3G, 3,5G? • Are there any hot-spots in the building that need special attention?
Handover Considerations Inside BuildingsThe indoor DAS system implemented in the building should be preparedfor future traffic growth. The best way to prepare this is to have a sector plan for futuresectorization of the system.Even if the system is implemented as one sector, you need to look ahead,especially for UMTS, in order to prepare for more sectors.Well-defined HO zones are important for GSM and UMTS/HSDPA to avoid‘ping-pong’ HO on GSM, extensive soft HO zones on UMTS and degradedHSPA performance.As a general rule you must try to avoid having the handover zones in largeopen areas inside the building. Here it can be difficult to design andcontrol the handover zoneTry to advantage of the natural isolation provided by the building toseparate the different sectors or cells.eg. Floor separation
The typical GSM handover scenario in a building Sec 1 HO HO Sec 1lift Sec 2 One way hand over to all IB cells HO MACRO MACROSec 5 HO Sec 2 Dominance COVERAGE Sec 3 Two way hand over to all IB cells HO Sec 3 HO Sec 4 HO HAND OVER ZONE Sec 4
Materials For IBSCoax Cablecoax cable is widely used in all types of distributed antennasystems, especially in passive systems.. Typical losses for the commonly used types of passive coaxialCables are mentioned Below
RF connectorcoaxial RF connector is an electrical connector designed to work at radio frequenciesin the multi-megahertz range. RF connectors are typically used with coaxial cables andare designed to maintain the shielding that the coaxial design offers. Better models alsominimize the change in transmission line impedance at the connection. Mechanicallythey provide a fastening mechanism (thread, bayonet, braces, push pull) and springsfor a low holmic electric contact while sparing the gold surface thus allowing above1000 reconnects and reducing the insertion force. Research activity in the area of radio-frequency (RF) circuit design has surged in the last decade in direct response to theenormous market demand for inexpensive, high data rate wireless transceivers .N andDIN type connectors are commonly used in IBS
AntennaAn antenna gives the wireless system three fundamental properties: gain, directionand polarization. Gain is a measure of increase in power. Gain is the amount ofincrease in energy that an antenna adds to a radio frequency (RF) signal. Direction isthe shape of the transmission pattern. As the gain of a directional antenna increases,the angle of radiation usually decreases. This provides a greater coverage distance,but with a reduced coverage angle. The coverage area or radiation pattern ismeasured in degrees. These angles are measured in degrees and are called beamwidths. Omni Antenna panel Antenna
SplittersSplitters and power dividers are the most commonly used passive components indistributed antenna systems. Splitters are used for splitting one coax line into two or more lines,and vice versa. If splitting to two ports, only half-power minus the insertion loss, typically about0.1 dB, is available at the two ports. It is very important to terminate all ports on the splitter;do not leave one port open. If it is unused, terminate it with a dummy load.You can calculate the loss through the splitter:splitter loss =10 log (number of ports)+ insertion lossFor a 1:3 splitter ,the attenuation will be:10 log(3)+0.1dB+4.87dB2Way splitter 4Way splitter 3Way splitter
TapersTapers are used like splitters, used to divide the signal/power from one intotwo lines. The difference from the standard 1:2 splitter is that the power isnot equally divided among the ports. In put Through port Couple port dB dB dB dB dB
Attenuators Attenuators attenuate the signal with the value of the attenuator.Attenuators are used to bring higher power signals down to a desired rangeof operationThe different ranges are 10dB,20dB,30 dB 40dB & variable attenuator
Dummy Loads or TerminatorsTerminators are used as matching loads on the transmission lines,often on one port of a circulator, or any ‘open’ or unused ports on othercomponents. 50W 10W
3 dB Coupler (90 Hybrid)The 3 dB coupler are mostly used for combining signals from twosignal sources. At the same time the coupler will split the two combinedsignals into two output ports. At the time of using this product two things are very important •Power handling capacity of each port •Isolation between 2 ports
Hybrid CombinerHybrid combiner mostly used for combining signals from two differentsignal sources The insertion loss is 3 dB
For creating a good IBS site the implementation quality have a major roll •Use trained and skilled manpower for Installations •Antennas should be fixed as per the design •All the splitters ,couplers are fixed properly and easy to maintain •All connectors should be tight •Make sure cable and jumpers are not bend sharply and no physical damage •All junctions should be covered with weather proof •Use proper tools for implementation •The VSWR should be <1.3 •Use 3 pin top with proper power rating power cable for any type of electrical power taping •All power and earth connections should be tight •Prepare and submit the proper AS Built report to the operator
Tools RequiredDrilling Machine •Hack saw •Sleaving tool •Knife •Spanners •Screw driver set •Cutting player
The most important thing in the IBS is the quality test ,because for getting a quality network we have to check the quality of allpart of the IBS Check the product quality •Is all the products are in ETSI Standard •The VSWR is with in the threshold •The performance is as per the specifications Implementation Quality All the connectors should be tight There is no sharp bending in RF cable All the junctions are protected from moisture The VSWR should be <1.3 Network Quality Do the walk test Check all the parameters are ok(DLRXL,DLRXQ,UL Level ULRXQ,SQ, Short call ,Long call ,Cell selection and reselection,Hand over,& no co and adjacent channel interference )
•The O&M Team /Engineer should have the as built design of the site•He have a good knowledge in passive and active components•The team have proper tools•Walk test tool(Nemo or TEMS)•Tool kit (installation tools)•Site master/spectrum analyzers