InBuilding Coverage

 Why We Need InBuilding Coverage

• Normally two reasons to build an indoor site   :

    * improve poor indoor coverage  

    * free capacity to outdoor cells

• Indoor cell's interference area vs outdoor cell's interference area is very limited

• Problem: Strong signals coming from outdoors to indoors

•  Buildings   

    * public (shopping malls, railway stations etc.) -> improves the network   quality and service -> operator finance  

    * private (companies etc.) -> possibility to sell mobile services -> possibility   to offer special tariffing -> tie up the company to operator

There are many Things we Must Prepare for Inbuilding Coverage (SIte Acquisition)

1 Specify customer requirements  

2 Before planning find out information of surrounding network (use template)  

3 Ask building owner's permission to do an indoor cell before starting the planning 

4 Give to building owner information of upcoming installation  

5 Prepare a target building list  

6 Customer accept the target buildings (if not new site acquisition

 7 After planning ask building owner to give the final permission to start implementation

SITE SURVEY 

• Acquire floorplan maps of the building

• Try to estimate the usage of mobile phones inside the building   

   * erlangs  * heavy-, normal-, occasional users

• Pre-survey to find out roughly    

     * antenna placement  * cable runs  * how to feed the system  * BTS location

• Budgetary cost estimation to get customer approval to the final design

• Take pictures of every antenna placement

• Use the information gathered in site acquisition template

• Site survey with implementation person 

• Try to optimize the number of antennas 

• Measure the coverage area of every antenna

DESIGN and Documentation

• Documentation consists of   

  * power budget calculation  

  * system diagram  

  * solution description

• Power budget calculation is needed to know EIRP values

• In indoor use EIRP is normally between 10 - 20 dBm  

    * to minimize signal spillage outdoors  

    * because of several splitters, couplers and cable losses in distribution network 

    * approximately same EIRP value to every antenna -> even coverage area

• System diagram describes the components and how those are used in distribution network

 

• Solution description describes where and how the distribution network is done

    * coverage area   

    * used components   

    * antenna network configuration  

     * BTS accommodation  

     * power supply

• Get implementation acceptance to the system diagram

•Frequency and parameter plan

  

Next .. we talk about Syatem Diagram, Propagation etc.