Wireless mobile and connection - Quiz

MIMO (Multiple Input Multiple Output) is one of the forms of smart antenna technology used in wireless communication systems. The other forms of smart antenna technology include MISO (multiple input, single output) and SIMO (single input, multiple output). MIMO technology uses multiple antennas at both the source and the destination to transmit and receive data signals, resulting in improved data rates and increased capacity.

Cordless telephone systems are wireless, but their drawback is limited coverage area, with a cell size of approximately 300 meters. However, being digital, they offer less chance of eavesdropping.

In second generation networks, Interim Standard 95 (IS-95) is the most widely used CDMA standard, as opposed to IS-136, a TDMA standard for 2G. EDGE is a 2.5G standard and ETACS is a 1G standard.

Electromagnetic signals traveling through wireless channels may experience fading effects due to various obstacles. However, in some cases, transmissions occur with no obstruction and direct line of sight, such as in satellite communication, microwave, and wireless line of sight radio links. Wired telephone systems do not undergo free space propagation as they rely on physical cables to transmit signals.

Level crossing rate (LCR) and average fade duration of a Rayleigh fading signal are essential statistics that are useful in designing error control codes and diversity schemes for mobile communication. Rayleigh fading is a type of fading where the amplitude and phase of the signal change randomly with time due to the multipath propagation environment.

Several techniques, such as phase-locked discrimination, slope detection, zero-crossing detection, and quadrature detection, are used for demodulating FM signals. Product detector is used for demodulating AM signals.

Lattice equalizer is a digital signal processing technique used in communication systems. It is used to equalize the channel distortion caused by the physical characteristics of the transmission medium. The lattice equalizer structure is more complicated than a linear transversal equalizer, but it has several advantages that make it a popular choice for equalization in communication systems. One of the advantages of the lattice equalizer is faster convergence. The equalizer can achieve a steady-state solution in a shorter time compared to other equalization techniques. Another advantage is numerical stability. The equalizer is designed to be numerically stable, which means it can handle small changes in the input data without causing large errors in the output data. This is an important property for a communication system since data transmission may be subject to noise and interference. The lattice equalizer also has a unique structure that allows for dynamic assignment of the most effective length of the equalizer. This makes it suitable for channels with varying characteristics, and it can adapt to changes in the channel condition in real-time. However, a simple structure is not one of the advantages of the lattice equalizer. In conclusion, the lattice equalizer has several advantages, including faster convergence, numerical stability, and dynamic assignment. While the structure of the equalizer is more complicated than a linear transversal equalizer, its unique structure and properties make it a popular choice for equalization in communication systems.

Block codes are a type of error-correcting code used in digital communication systems to detect and correct errors that occur during transmission. They are linear, systematic, and cyclic in nature. Linearity means that the output of the code is a linear combination of its input. In other words, the code is a linear function that maps input sequences to output sequences. This is a desirable property because linear functions can be easily analyzed and implemented. Systematic means that the input message bits are directly transmitted along with the parity bits. The transmitted message is in a systematic form where the input message is preserved in the transmitted sequence. Cyclic means that if a codeword is cyclically shifted, the result is another codeword. This property simplifies the encoding and decoding process and reduces the computational complexity of the system. However, block codes are not nonlinear in nature. Nonlinear codes are more complex and harder to analyze and implement than linear codes. Therefore, block codes are usually preferred over nonlinear codes in digital communication systems.

First-generation wireless systems primarily provide analog speech and inefficient, low-rate data transmission between the base station and mobile user.

SS7 network offers three main types of services: Touchstar, 800 services, and alternate billing services. 400 services are not among the services provided by SS7.