16-01-2013, 09:40 AM
A Project Report on Quality of BTS Site
Introduction
A base transceiver station or cell site (BTS) is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets), WLL phones, computers with wireless internet connectivity, WiFi and WiMAX gadgets etc. The network can be that of any of the wireless communication technologies like GSM, CDMA, WLL, WAN, WiFi, WiMAX etc. BTS is also referred to as the radio base station (RBS), node B (in 3G Networks) or, simply, the base station (BS). For discussion of the LTE standard the abbreviation eNB for enhanced node B is widely used. So, to understand BTS we have to go through the basics of GSM system because BTS is a part of a GSM system.
Radio Path Control
In the GSM network, the Base Station Subsystem (BSS) is the part of the network taking care of Radio Resources, i.e. radio channel allocation and quality of the radioconnection. For this purpose, the GSM Technical Specifications define about 120different parameters for each BTS. These parameters define exactly what kind of BTSis in question and how MSs may "see" the network when moving in this BTS area.The BTS parameters handle the following major items: what kind of handovers (whenand why), paging organization, radio power level control and BTS identification.
BTS and TC Control
Inside the BSS, all the BTSs and TCs are connected to the BSC(s). The BSC maintains the BTS. In other words, the BSC is capable of separating (barring) a BTSfrom the network and collecting alarm information. Transcoders are also maintainedby the BSC, i.e. the BSC collects alarms related to the Transcoders Synchronization. The BSS uses hierarchical synchronization which means that the MSC synchronizesthe BSC and the BSC further synchronizes the BTSs associated with that particularBSC. Inside the BSS, synchronization is controlled by the BSC. Synchronization is acritical issue in the GSM network due to the nature of the information transferred. Ifthe synchronization chain is not working correctly, calls may be cut or the call qualitymay not be the best possible. Ultimately, it may even be impossible to establish a call.
Air &A Interface Signaling:
In order to establish a call, the MS must have a connection through the BSS. This
Connection requires several signaling protocols.
Connection Establishment between MS and NSS
The BSS is located between two interfaces; the Air and the A interface. From the callestablishment point of view, the MS must have a connection through these twointerfaces before a call can be established. Generally speaking, this connection may beeither a signaling type of connection or a traffic (speech, data) type of connection.
Network Management Subsystem
The Network Management Subsystem (NMS) is the third subsystem of the GSM
Network in addition to the Network Switching Subsystem (NSS) and Base StationSubsystem (BSS). The purpose of the NMS is to monitor various functions andelements of the network. These tasks are carried out by the NMS/2000 which consistsof a number of Work Stations, Servers and a Router which connects to a DataCommunications Network (DCN).
The operator workstations are connected to the database and communication serversvia a Local Area Network (LAN). The database server stores the managementinformation about the network. The communications server takes care of the datacommunications between the NMS and the equipment in the GSM network known as Network Elements These communications are carried over a Data CommunicationsNetwork (DCN) which connects to the NMS via a router. The DCN is normallyimplemented using an X.25 Packet Switching Network.
Fault Management
The purpose of Fault Management is to ensure the smooth operation of the network
and rapid correction of any kind of problems that are detected. Fault management
provides the network operator with information about the current status of alarm
events and maintains a history database of alarms. The alarms are stored in the NMSdatabase and this database can be searched according to criteria specified by thenetwork operator.
Configuration Management
The purpose of Configuration Management is to maintain up to date information aboutthe operation and configuration status of network elements. Specific configurationfunctions include the management of the radio network, software and hardwaremanagement of the network elements, time synchronization and security operations.