TelecomStudy18

All data communication codes are based on the binary system (1s and 0s). A message can be encoded into a meaningful string of 1s and 0s that can be transmitted along a data line and decoded by a receiver. The string of 1s and 0s is meaningful because it is defined by a code that is known to both the source and the receiver. Code is limited by the number of bits (binary digits) it contains, e.g. one-bit code means that we can have 2 characters so that we can encode the letter A by '0' and B by '1'. Similarly, a 2 bit code will enable us to handle 4 characters. Thus, a n-bit code enables us to handle 2 n characters.  Some commonly used codes are : 1.              Baudot code 2.              ASCII code 3.              BCDIC code 4.              EBCDIC Code ASCII Code (American Standard Code for Information Interchange) It is an eight-bit code which consists of seven information bits and one bit for parity checking. This is most widely used data code. Se

TEMS CellPlanner Universal is Ericsson´s tool for mobile radio network planning. It is a highly graphical, easy-to-use, PC-based tool for design, realization, and optimization of mobile radio networks. TEMS CellPlanner Universal helps the user to roll out and expand mobile radio networks, and optimize radio network regarding service availability and service quality. It assists the user in a number of complex tasks, including network dimensioning, traffic planning, site configuration, and frequency planning. TEMS CellPlanner Universal is the key to successfully competing in the market place. TEMS CellPlanner Universal provides support for WCDMA, GSM 850, GSM 900, GSM 1800, GSM 1900, iDEN, CDMA, CDMA2000 1xRTT, TDMA/AMPS, NMT 450, NMT 900, TACS, and E-TACS. TEMS CellPlanner Universal also provides support for GPRS and EGPRS (EDGE), implemented in GSM system The modular platform makes it possible to customize TEMS CellPlanner Universal to meet the needs of every customer. TEMS Ce

For understanding the data communication following terminology is discussed: - ·         Communication lines The medium that carries the message in a data communication system, example of  A 2W telephone line.    Communication Channel A channel is defined as a means of one way transmission. It can carry information in either direction but in only one direction at a time, e.g. A hose pipe. It can carry water in either direction, but the direction of flow depends on which end of pipe is connected to the water tap.  Simplex Transmission 1.     Message always flows in one direction only. 2.     An input Terminal can only receive and never transmit. 3.     An O/P Terminal can only transmit and never receive. Half Duplex Transmission -         A half duplex channel can transmit and receive but not simultaneously. -         Transmission flow must halt each time and direction is to be reversed. -         This halt is called the turn-around time and is typical

There are three types of HDLC frames : ·          Information transfer frame (I-Frame) ·          Supervisory frame (S-Frame) ·          Unnumbered frame (U-Frame) Information Transfer Frame (I-FRAME) I-Frame is used for transporting user data. It also carries acknowledgement of the received frames. The control field of the I-Frame is as shown in Fig.7. The first bit is 0 which identifies the frame as an I-Frame. The next three bits are the sequence number N(S) of the frame. The fifth is Poll/Final (P/F) bit. Its use is explained later. The last three bits are the sequence number N(R) of the acknowledgement (RR) which is piggy backed on the I-Frame.  S upervisory f rame (S-FRAME) S-Frame does not have data field (Fig.3b) and is used to carry only acknowledgements, requests for retransmission, etc. It is identified by the first two bits of the control field (Fig. 8). These two bits are 10 in an S-Frame. The next two bits (SS) are used to indicate four supe

 HDLC  was developed by ISO and has become the most widely accepted data link protocol. It offers a high level of flexibility, adaptability, reliability and efficiency of operation for today as well as tomorrow's synchronous data communication needs. ADCCP developed by ANSI is almost similar to HDLC, IBM'S SDLC is a proper subset of HDLC and level 2 of X-25 is a permissible option of HDLC. In this chapter, we shall study the basic features and operation of HDLC protocol. Certain liberties have been taken in the level of completeness of description so as not to cloud the overall picture with the details. GENERAL FEATURES of hdlc    HDLC is a bit oriented data link control protocol which satisfies wide variety of data link control requirements including: ·          Point-to-point and point-to-multipoint links. ·          Two way simultaneous communication over full duplex circuits. ·          Two way alternate operation over half duplex or full duplex circuits. ·

ERROR DETECTION When a code word is transmitted, one or more of its bits may be reversed due to signal impairment. The receiver can detect these errors if the received code word is not one of the valid code word of the code set. If the corrupted received word becomes another valid code word, the error cannot be detected. When error occurs, the distance between the transmitted and received code words is equal to the number of erroneous bits . as showing in given below figure. TRANSMITTED CODE WORD RECEIVED CODE WORD NUMBER OF ERRORS DISTANCE 11001100 11001110 1 1 10010010 00011010 2 2 10101010 10100100 3 3 In other words the valid code words must be separated by a distance more than 1 else even a single bit error will generate another valid code word and the error will not be detected. The number of errors which can be detected

Errors are introduced in the data bits during their transmission across a sub network. These errors can be categorised into : ·           Content errors ·           Flow integrity errors Content errors are the errors in the content or a message, e.g. a "1" may be received as "0". This type of errors gets introduced due to impairment of the electrical signal in the transmission media. Flow integrity errors refer to missing blocks of data. For example, a data block may be lost in the sub-network due to its having been delivered to a wrong destination. In voice communication, the listener can tolerate a good deal of signal corruption during transmission. But data is very sensitive to errors. Measures are, therefore, built into a data communication system to counteract the effect of errors. These measures include: ·                      Introduction of additional check bits in the data bits to detect and correct content errors. ·                      Es

The International Organization introduced the OSI layer for Standardization (ISO) in 1984 in order to provide a reference model to make sure products of different vendors would interoperate in networks. OSI is short for Open System Interconnection. The OSI layer shows WHAT needs to be done to send data from an application on one computer, trough a network, to an application on another computer, not HOW it should be done.  A layer in the OSI model communicates with three other layers: the layer above it, the layer below it, and the same layer at its communication partner. Data transmitted between software programs passes all 7 OSI layers. The Application, Presentation and Session layers are also known as the Upper Layers. The Data Link and Physical layers are often implemented together to define LAN and WAN specifications.   Application Layer (Layer 7) Application Layer provides network services directly to applications. Type of software programs vary a lot: from groupw

Let us now understand the difference between transmission and communication. Transmission means physical movement of information from one point to another. Communication means meaningful exchange of information between the communicating devices. Example Two persons, one knowing English language only and the other knowing French language only cannot communicate with each other. Here transmission is taking place, but communication is not there. Therefore, for communication, we need much more than the transmission. For communication, we must have the same language, i.e. Data codes should be understood both by transmitter and the receiver. Moreover, receiver should be in a position to receive, i.e. Timing is also very important. We have two types of communication : (1)                Synchronous Communication. (2)                Asynchronous Communication. Synchronous Communication In Synchronous communication the exchange of information is in a well disciplined manner, e

The features Remote OMT (Operation and Maintenance Terminal) and Remote OMT over IP are updated to support the new RBS 6000 DUG-20/RUS-01 configurations. In MCPA backwards compatible mode, having a BTS G11A or newer in a BSS 07B-G10B network, the configuration of an MCPA is made using OMT. Configuration in MCPA single mode (BTS G11B with BSS G10B or newer) is made from the BSC, refer to Section 5.7 on page 43. All TRXs in a DUG are connected to one or several RUSs. It is the connections between RUSs and antennas that will decide which MCPAs to use for which antenna sectors (cells). Each antenna sector is configured in the OMT with the default configuration of 3*20W (3*43.0 dBm) per MCPA. If desired it is possible to choose a different number of TRXs per MCPA, and it is possible to choose some configurations where the total MCPA mean power will end up on less than 60 W (47.8 dBm). Also the levels 40W (46.0 dBm) and 20W (43.0 dBm) are available. The chosen number of TRXs

The RBS 6000 Radio Units have built-in functionality for what would otherwise require external equipment so there is no need for installation of extra hardware for supervision and power feed for TMAs. The radio units in RBS 6000 will provide the power and also supervise standard TMAs by monitoring the current consumed by the TMA. Commands: • RXBFC, Radio X-ceiver Administration, BTS Feature Data, Change The parameter to activate Standard TMA (CSTMA) is added to this existing command. Printouts: • RADIO X-CEIVER ADMINISTRATION BTS FEATURE DATA (command RXBFP) • RADIO X-CEIVER ADMINISTRATION MANAGED OBJECT CONFIGURATION DATA (command RXCDP)

Automatic IRC Tuning is used instead of Automatic FLP by operators that wants to maximize IRC (and SAIC) performance but do not use FLP. As with Automatic FLP, the feature performs daily downlink interference matrix measurements and creates synchronization clusters for synchronization status monitoring. TSC and FSOFFSET parameters are continuously supervised and automatically adjusted to network changes when needed. By using Automatic IRC Tuning an operator will get the following benefits: >Automatic configuration of IRC (Interference Rejection Combining) related parameters: - TSC for hopping channel groups. - FSOFFSET for neighbor cells that are GPS synchronized. By this co-TSC interference can be suppressed. > Maximum gain from IRC and SAIC. > Possibility to monitor synchronization status for Synchronized Radio Network cells. Automatic IRC Tuning is allowed to be activated in the same BSC as Automatic FLP. When both features are active in the same cell it