Explanation: One of the main problems with adjacent channel interference is the near-far effect. It occurs when a mobile close to a base station transmits on a channel close to one being used by a weak mobile.

Explanation: Micro cell zone concept distributes the coverage of the cell and extends the cell boundary to hard-to reach places. It is the solution for the problem of increased number of handoffs when sectoring which results in an increase of load on switching.

Explanation: EM signals when traveling through wireless channels experience fading effects due to various effects. But in some cases the transmission is with no obstruction and direct line of sight such as in satellite communication, microwave and wireless line of sight radio links.

Explanation: Reflection occurs when a propagating electromagnetic wave impinges upon an object which has very large dimensions when compared to the wavelength of the propagation wave. Reflection occurs from the surface of the Earth and from buildings and walls.

Explanation: The concept of diffraction loss is a function of the path difference around an obstruction. It can be explained by Fresnel zones. Fresnel zones represent successive regions where secondary waves have a path length from Tx to Rx which are nλ/2 greater than total path length.

Explanation: Log normal shadowing, log distance path loss model and determination of percentage of coverage area are practical pat loss estimation techniques. Hata model is only valid for exterior environment.

Explanation: Okumura’s model is one of the most widely used models for signal prediction in urban areas. This model is applicable for frequencies in the range 150 MHz to 1920 MHz (Extrapolated upto 3000 MHz).

Explanation: Rapid changes in signal strength over a small travel distance are caused due to multipath. It causes random frequency modulation due to varying Doppler shifts on different multipath signals. Time dispersion is also caused by multipath propagation delays.

Explanation: The main problem with RF pulse system is that it is subject to interference and noise. This is due to wide passband filter required for multipath time resolution.

Explanation: The mean excess delay, excess delay spread and rms delay spread are some multipath channel parameters. They can be determined from a power delay profile. Doppler spread is a measure of spectral broadening caused by time rate of change of mobile radio channel.

Explanation: Channel parameters are coherence bandwidth, rms delay spread and Doppler spread. Signal parameters are bandwidth and symbol period. Different types of fading occur depending on the relation between channel and signal parameters.

Explanation: The level crossing rate (LCR) and average fade duration of a Rayleigh fading signal are important statistics. They are useful for designing error control codes and diversity schemes to be used in mobile communication.

Explanation: Three principle shape factors are angular spread, angular constriction, and azimuthal direction of maximum fading. They are exactly related to the average rate at which a received signal fades.

Explanation: Various techniques such as slope detection, zero crossing detection, phase locked discrimination and quadrature detection are used to demodulate FM. Product detector is used for demodulating AM signals.

Explanation: Bandwidth efficiency reflects how efficiently the allocated bandwidth is utilized. It is defined as the ratio of throughput data rate per Hertz in a given bandwidth. It describes the ability of a modulation scheme to accommodate data within a limited bandwidth.

Explanation: OQPSK, π/4 QPSK and BPSK are the most popular linear modulation techniques. They have very good spectral efficiency. However, FSK is an non-linear modulation technique.

Explanation: MSK has a constant envelope. It is a spectrally efficient scheme. It possesses properties such as constant envelope, spectral efficiency, good BER performance and self-synchronizing capability.

Explanation: The set of possible carrier frequencies in FH-SS is called hopset. Hopping occurs of a frequency band that includes a number of channels. Each channel is defined as a spectral region with central frequency in the hopset.

Explanation: Outage event is specified by a specific number of bit errors occurring in a given transmission. Evaluating the probability of outage is one of the means to judge the effectiveness of the signalling scheme in a mobile radio channel.

Explanation: Equalization, diversity and channel coding are the three techniques which are used to improve received signal quality and link performance over small scale times and distance. But, the approach, cost, complexity and effectiveness varies in wireless communication system.