Index

1. BSNL2. Services of BSNL3. Base Station Controller(BSC)4. Base Transceiver System(BTS)5. Mobile Switching Centre(MSC)6. Mobile BTS7. Base Station Subsystem(BSS)

Site VisitBTS Main Sections

POWER SECTION POWER PLANT BTS MACHINE TOWER & ANTENNA

BTS Machine Parts: POWER CARDS BB2F TRX BOIA CARD ALARM EXTENSION SYSTEM

RRI CARD COUPLER DUPLEXER

Call Process

Network technology: GSM Technology CDMA Technology WiMAX Technology

BSNLBharat Sanchar Nigam Limited (abbreviated BSNL) is an Indian state-owned telecommunications company headquartered in New Delhi. It was incorporated on 15 September 2000 and took over the business of providing of telecom services and network management from the erstwhile Central Government Departments of Telecom Services (DTS) and Telecom Operations (DTO), with effect from 1 October 2000 on a going concern basis. It is the largest provider of fixed telephony and broadband services with more than 60% market share and Fifth largest mobile telephony provider in India. However, in recent years the company's revenues and market share have plummeted into heavy losses due to intense competition in the Indian telecommunications sector. BSNL is India's oldest communication service provider and had a customer base of 93.29 million as of June 2015. It has footprints throughout India except

for Mumbai and New Delhi, which are managed by Mahanagar Telephone Nigam (MTNL).

Services:

BSNL Mobile is major provider of GSM cellular mobile services under the brand name Cell one. BSNL provides complete telecom services solution to enterprise customers including MPLS, P2P and Internet leased lines. It provides fixed line services and landline using CDMA technology and its extensive optical fibre network. BSNL provides Internet access services through dial-up connection as prepaid, Net One as Post-paid and Data One as BSNL Broadband.BSNL offers value-added services, such as Free Phone Service (FPH), India Telephone Card (Prepaid card), Account Card Calling (ACC), Virtual Private Network (VPN), Tele-voting, Premium Rate Service (PRM), Universal Access Number (UAN). BSNL also offers the IPTV which enables customers to watch television through internet and Voice and Video over Internet Protocol (VoIP). In 2007, BSNL announced plans for providing 5 million broadband connectivity and secured 80% of the INR 25 billion rural telephony project of Government of India. On 20 March 2009, BSNL launched blackberry services across India. BSNL paid Rs. 101.87 billion for 3G spectrum in 2010. As of 2011, BSNL offers coverage in over 800 cities across India. BSNL launched in 2012 a 3G wireless pocket router named Wink net Mf50. BSNL 3G provides HSPA+ service with highest speed of 21.1 Mbit/s downlink and 5.76 Mbit/s uplink.

BSNL announced the discontinuation of its telegram services from 15 July 2013, after 160 years in service. It was opened to the public in February 1855; it was upgraded to a web-based messaging system in 2010, through 182 telegraph offices across India.

BSC(Base Station Controller) The Base Station Controller (BSC) controls and supervises the radio resources in the Base Transceiver Station (BTS). Together with the BTS, the BSC constitutes the Base Station System (BSS), responsible for the management and cell configuration data of the radio network. The main functions of the BSC are:

1. Administration of BSS resources2. Supervision of the BTS3. Connection handling of mobile stations4. Locating and handover5. Administration of paging6. Transmission network management7. Operation and maintenance of the BSS

The unit that performs the speech conversion from 64 kbit/s into a total of 16k or 8k, 13+3kbit/s and 15.1+0.9kbit/s (Full rate and Enhanced speech coder, FR and EFR) or 6.5+1.5 kbit/s (Half rate speech codec, HR) per channel is called the transcoder. This function can either be placed in a separate node, called the Transcoder Controller (TRC), or together with the BSC, which then becomes a BSC/TRC. The different configuration types are illustrated in the picture below.

TRC - a Stand Alone   transcoder   controller node The TRC node allows a flexible location of the transcoder resources. Typically, the TRC is located at or near the MSC. It is controlled by the BSC. 16 BSCs can be connected to one TRC.

BSC/TRC - a combined BSC and   transcoder   controller The BSC/TRC is suitable for medium and high capacity BSC applications, that is, urban and suburban area networks. This node can handle up to 1,020 Transceivers (TRXs). 15 standalone BSCs can be connected to the BSC/TRC.

BSC - a Stand Alone BSC without   transcoders The BSC is optimized for low and medium capacity BSS networks and is a complement to the BSC/TRC, especially in rural and suburban areas. For GSM 900/GSM 1800, it can handle up to 1,020 TRXs

BTS (Base Transceiver Station)

A Base transceiver station (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. The network can be that of any of the wireless communication technologies

like GSM, CDMA, wireless local loop, Wi-Fi, WiMAX or other wide area network(WAN) technology.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 evolved node B is widely used.Though the term BTS can be applicable to any of the wireless communication standards, it is generally associated with mobile communication technologies like GSM and CDMA. In this regard, a BTS forms part of the base station subsystem (BSS) developments for system management. It may also have equipment for encrypting and decrypting communications, spectrum filtering tools (band pass filters), etc. Antennas may also be considered as components of BTS in general sense as they facilitate the functioning of BTS. Typically a BTS will have several transceivers (TRXs) which allow it to serve several different frequencies and different sectors of the cell (in the case of sectorised base stations). A BTS is controlled by a parent Base station controller via the base station control function (BCF). The BCF is implemented as a discrete unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance (O&M) connection to the network management system (NMS), and manages operational states of each TRX, as well as software handling and alarm collection. The basic structure and functions of the BTS remains the same regardless of the wireless technologies.

General Architecture of BTS : A BTS is usually composed of:

Transceiver (TRX)Quite widely referred to as the driver receiver (DRX), DRX are either in form of single (sTRU), double(dTRU) or a composite double radio unit (DRU). It basically does transmission and reception of signals. It also does sending and reception of signals to and from higher network entities (like the base station controller in mobile telephony).

Power amplifier (PA)Amplifies the signal from DRX for transmission through antenna; may be integrated with DRX.

CombinerCombines feeds from several DRXs so that they could be sent out through a single antenna. Allows for a reduction in the number of antenna used.

MultiplexerFor separating sending and receiving signals to/from antenna. Does sending and receiving signals through the same antenna ports (cables to antenna).

AntennaThis is the structure that the BTS lies underneath; it can be installed as it is or disguised in some way (Concealed cell sites).

Alarm extension systemCollects working status alarms of various units in the BTS and extends them to operations and maintenance (O&M) monitoring stations.

Control functionControls and manages the various units of BTS, including any software. On-the-spot configurations,

status changes, software upgrades, etc. are done through the control function.

Baseband receiver unit (BBxx)Frequency hopping, signal DSP.

MSC(Mobile Switching Center):

The Mobile switching center (MSC) is the primary service delivery node for GSM/CDMA, responsible for routing voice calls and SMS as well as other services (such as conference calls, FAX and circuit switched data).The mobile switching station, abbreviated as MSC Server or MSS, is a 2G core network element which controls the network switching subsystem elements. Alternatively or adaptively, MSS can be used in GSM networks as well, if the manufacturer has implemented support for GSM networks in the MSS.Alternatively MSS is also called an MTS-U (Motorola telephony soft-switch) in Motorola terminology and as MSC-S in Ericsson terminology. MSC server functionality enables split between control plane (signaling) and user plane (bearer in network element called a media gateway), which guarantees better placement of network elements within the network.

MSC server and MGW make it possible to cross-connect circuit switched calls switched by using IP, ATM AAL2 as well as TDM.

Mobile BTS :

Diversity technique

To improve the quality of the received signal, often two receiving antennas are used, placed at a distance equal to an odd multiple of a quarter of the corresponding wavelength.

For 900 MHz, this wavelength is 30 cm. This technique, known as antenna diversity or space diversity, avoids interruption caused by path fading.

The antennas can be spaced horizontally or vertically. Horizontal spacing requires more complex installation, but brings better performance.

Other than antenna or space diversity, there are other diversity techniques such as frequency/time diversity, antenna pattern diversity, and polarization diversity.

Splitting refers to the flow of power within a particular area of the cell, known as a sector. Every field can therefore be considered like one new cell.Directional antennas reduce LoRa (Long Range) interference. If not sectorised, the cell will be served by an omnidirectional antenna, which radiates in all directions.

A typical structure is the trisector, also known as clover, in which there are three sectors served by separate antennas. Each sector has a separate direction of tracking, typically of 120° with respect to the adjacent ones. Other orientations may be used to suit the local conditions.

Bisectored cells are also implemented. These are most often oriented with the antennas serving sectors of 180° separation to one another, but again, local variations do exist.

BSS(Base Station Subsystem):The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of speech channels, allocation of radio channels to mobile phones, paging, transmission and reception over the air interface and many other tasks related to the radio network.

SITE VISIT(TOWER VISIT)

BTS HAS A MAIN SECTIONS :

1. POWER SECTION 2. POWER PLANT3. BTS MACHINE4. TOWER & ANTENNA

Power Station :POWER SUPPLY IS GET FROM THREE WAYS :

1. GEB LINE2. GENERATOR3. BATTERYS

Power Plant : Power plant is used in BTS to obtain -48v dc from 440v ac supply.

BTS MACHINE

BTS Divided in to following Parts:1. POWER CARDS2. BB2F3. TRX4. BOIA CARD5. ALARM EXTENSION SYSTEM6. RRI CARD7. COUPLER8. DUPLEXER

Power Cards: First regulated -48 volt is comes from power plant and it give first to power card. it distribute supply to all equipment of BTS.

BB2F Cards :

Function of BB2F in BSNL BTS is digital signal processing and also Frequency hopping. One BB2F can operate 2 TRX. There are two condition of BB2F which is detected by leads…

1. green - Ok

2. red- Faulty

TRX(Transceiver)

TRX is Equipment which handles calls of user. One TRX can handle 8 calls per second. We can use maximum 12 TRX on one BTS. It is depend on bb2f card which maximum value is

6.

BOIA Cards :

BOIA card is used for software Programming. BOIA card is like brain of BTS. There are serial port in it for connect it to laptop.

The BOIA card in the BTS is for maintaining the total functionality of the BTS. It consists of a local management port(LMP) through which a system can be connected with Others

Alarm Extension Manager :

It collects working status of various units BTS and extend them to Operation & Maintenance (o & m) Monitoring Stations.

RRI Cards:

RRI card is used for connection of ODU (outdoor

unit). This antenna is used for microwave link which

connect one BTS to other BTS.

Multi Coupler:

When we use more than two TRX then it is require

to coupler and then it connect with Duplexer. One combiner is used to handle two TRX.

Duplexer:

Duplexer is a device which is used in BTS to use same antenna for Transmission as well as receiver.

Antenna has two cable one for TX & RX which connect with Duplexer.

Tower & Antenna: Tower is used to give height to antenna. Height of tower is 40m to 75m.

Antenna:There two antenna is used in BTS.

One for transmission & reception of user’s signals which is called GSM antenna.

Second antenna is microwave antenna which is used to get & forward link from other BTS.

Second antenna is also called as drum antenna.

Call Process In BSNL :

Steps: Mobile Station (MS) Dial a Number called as

Source Subscriber. Mobile Subscriber Details goes to its nearest

BTS Tower for Forwarding the Call to the Destination Subscriber.

BTS sends the Subscriber Information to BSC. BSC sends the Subscriber Information to

MSC. MSC has the All Information of Subscriber like

Balance etc., Then MSC check the Information and forward the call.

Network Technology:

1. GSM Technology :

GSM (Global System for Mobile Communications, originally Groupe SpécialMobile), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile phones, first deployed in Finland in July 1991. As of 2014 it has become the de facto global standard for mobile communications - with over 90% market share, operating in over 219 countries and territories.

Network structureThe network is structured into a number of discrete sections:Base Station Subsystem – the base stations and their controllers explained

Network and Switching Subsystem – the part of the network most similar to a fixed network, sometimes just called the "core network".GPRS Core Network – the optional part which allows packet-based Internet connectionsOperations support system (OSS) – network maintenance

CDMA Technology:

Code division multiple access (CDMA) is a channel access method used by various radio communication technologies.CDMA is an example of multiple accesses, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code).

CDMA is used as the access method in many mobile phone standards. IS-95, also called "CDMA One", and its 3G evolution CDMA2000, are often simply referred to as "CDMA"', but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as

well as TD-CDMA and TD-SCDMA, as its radio technologies.

WiMAX :WiMAX (Worldwide Interoperability for Microwave Access) is a family of wireless communication standards based on the IEEE 802.16 set of standards, which provide multiple physical layer (PHY) and Media Access Control (MAC) options.

The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard, including the definition of predefined system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL". IEEE 802.16m or Wireless MAN-Advanced is a candidate for the 4G, in competition with the LTE Advanced standard.

WiMAX was initially designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 GB/s for fixed stations.

Uses of WiMAX:The bandwidth and range of WiMAX make it suitable for the following potential applications:

Providing portable mobile broadband connectivity across cities and countries through a variety of devices.

Providing a wireless alternative to cable and digital subscriber line (DSL) for "last mile" broadband access.

Providing data, telecommunications (VoIP) and IPTV services (triple play).

Providing a source of Internet connectivity as part of a business continuity plant

Smart grids and metering

GPRS Technology:General Packet Radio Service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system's global system for mobile communications (GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and I-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).

GPRS usage is typically charged based on volume of data transferred, contrasting with circuit switched data, which is usually billed per minute of connection time. Sometimes billing time is broken down to every third of a minute. Usage above the bundle cap is charged per megabyte, speed limited, or disallowed.

GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service (QoS) is guaranteed during the connection. In 2G systems, GPRS provides data rates of 56–114 KB/second.2G cellular technology combined with GPRS is sometimes described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile telephony.[4] It provides moderate-speed data transfer, by using unused time division multiple access (TDMA) channels in, for example, the GSM system. GPRS is integrated into GSM Release 97 and newer releases.

The GPRS core network allows 2G, 3G and WCDMA mobile networks to transmit IP packets to external networks such as the Internet. The GPRS system is an integrated part of the GSM network switching subsystem.

Services:GPRS extends the GSM Packet circuit switched data capabilities and makes the following services possible:SMS messaging and broadcasting"Always on" internet accessMultimedia messaging service (MMS)Push-to-talk over cellular (PoC)Instant messaging and presence—wireless villageInternet applications for smart devices through wireless application protocol (WAP)Point-to-point (P2P) service: inter-networking with the Internet (IP)Point-to-multipoint (P2M) service [citation needed]: point-to-multipoint multicast and point-to-multipoint group calls.

Protocol Supported: Internet Protocol(IP) Point to point Protocol(PPP) X.25