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Content www. Amala Shanthi www. Classify the mobile radio transmission systems. State example for a half duplex system. Push to talk and release to listen. State example for a Simplex system. State the operations performed by control channel Call setup, call request, call initiation and other control purposes. Define page. A brief message which is broadcast over the entire service area in a simulcast fashion by many base station at the same time.
Define the term Roamer. A mobile unit that operates in a service area other than that from which service has been subscribed. Define handoff? When a mobile moves from one cell to another the control of this mobile is transferred from one cell to another.
This process is referred as handoff. Define cluster. The N cells which collectively use the complete set of available frequencies is called a cluster. Give the equation which illustrates the relation between capacity of a system and cluster size.
State the different classifications of channel assignment strategies. Fixed and dynamic. What is the use of RSSI? This is receive signal strength indicator. This information is sent to the cell site from the mobile unit so that the MTSO can decide for a handoff. Mention the type of handoff used in CDMA. Soft handoff.
State the different types of handoffs. Soft handoff, hard handoff, forced handoff, delayed handoff and mobile associated handoff. What is intersystem handoff? During a course of a call, if a mobile moves from one cellular system to a different cellular system controlled by a different MSC it is referred as intersystem handoff. What is co channel interference?
Interference between signals from cells that operate in same frequency is referred as channel interference. What is grade of service? It is a measure of the ability of a user to access a trunked system during the busiest hour. What is cell splitting? It is a process of subdividing a congested cell into smaller cells.
What is sectoring? The process of using directional antennas in a cell is referred as sectoring. State the different techniques used for improving coverage and capacity in cellular systems. Cell splitting, Sectoring, Repeaters for range extension and Microcell zone. Define modulation. It is the process of encoding information from a message source in a manner suitable for transmission.
What is frequency planning? The design process of selecting and allocating channel groups for all the cellular base stations within a system is called frequency planning. What is trunking efficiency? It is a measure of the number of users which can be offered a particular GOS with a particular configuration of fixed channels.
State the basic constituents of a cellular system. Mobile unit, cell site, mobile telephone switching office. State the two different types of fading. Define rayleigh fading. It refers to the variation in the received signal which is due to the waves reflected from surrounding buildings and other structures.
Define the term coherence bandwidth. It is defined as the bandwidth in which either the amplitudes or the phases of two received signals have a high degree of similarity. What is direct wave path? It is the path which is clear from the terrain contour. State the different analog modulation schemes. Amplitude and frequency modulation. State the different modulation schemes. Amplitude shift keying, frequency shift keying, phase shift keying.
Define amplitude modulation. The amplitude of the high frequency carried is varied in accordance to the instantaneous amplitude of the message signal. State the techniques used for SSB generation.
Filter method and balanced modulator method. State the advantages of digital modulation schemes. Power efficiency and bandwidth efficiency. Define bandwidth efficiency. It describes the ability of the modulation scheme to accommodate data within a limited bandwidth. Define Power efficiency. It describes the ability of the modulation scheme to preserve the fidelity of the digital message at low power levels.
State the different types of line coding. Return to zero, non-return to zero and Manchester. State the types of modulation schemes used in mobile communication. What is coherent detector?
If the receiver has prior knowledge of the transmitted signal then the receiver is known as coherent detector. Continuous phase frequency shift keying. It is another name for MSK. What is QAM? Quadrature amplitude modulation. What is a diversity receiver? Mention the three partially separable effects of radio propagation. The three partially separable effects of radio propagation are, Multi path fading Shadowing Path loss Mention the basic propagation mechanisms, which impact propagation in mobile communication.
The basic propagation mechanisms are, Reflection Diffraction Scattering What is reflection? Reflection occurs when a propagating electromagnetic wave impinges upon an object, which has very large dimension when compared to the wavelength of propagating wave. What is diffraction? Diffraction occurs when the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities.
What is scattering? Scattering occurs when the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength and where the number of obstacles per unit volume is large.
Define Brewster angle? The Brewster angle is the angle at which no reflection occurs in the medium of origin. Why we use 1mi intercept for mobile communication? Within a 1mi radius the antenna beam width of a high gain omni-directional antenna is narrow in vertical plan.
Larger the elevation angle weaker the reception level. What are the possible conditions in a point-to-point prediction model?
The possible conditions in a point to point prediction model are, Non Obstructive direct path. What are the merits of point-to-point model? The merits are, Produces an accurate prediction with a deviation of 8dB. Reduces the uncertainty range by including the detailed terrain contour information. What is a smart antenna? A smart antenna system consist of an antenna array, associated RF hardware and a computer controller that changes array pattern in response to radio frequency environment.
EC1451 Mobile Communication Syllabus
What is digital modulation? What is FSK? What is PSK? What is QAM? Define Spread-spectrum techniques.
To make the students to know about the various modulation techniques, propagation methods, coding and multi access techniques used in the mobile communication. Various wireless network systems and standards are to be introduced. This also demonstrates the principle of trunking efficiency and how trunking and interference issues between mobile and base stations combine to affect the overall capacity of cellular systems. This also covers small propagation effects such as fading, time delay spread and Doppler spread and describes how to measures and model the impact that signal bandwidth and motion have on the instantaneous received signal through the multi-path channel. It also deals with the different types of equalization techniques and diversity concepts. This unit also describes the time, frequency code division multiple access techniques as well as more recent multiple access technique such as space division multiple access.
Ec1451 Mobile Communication
Tagor What are the 3 kinds of polarization? Define uncertainty principle of Quantum mechanics. What is network security? What are the Different types of Routing Agents in mobile networking? Search for Question Papers: This unit also describes the time, frequency code division multiple access techniques as well as more recent multiple access technique such as space division multiple access. Define wireless routing protocol.