Scientific paper ID 1917 : 2020/2

Georgi Dimitrov

Spectral efficiency in wireless networks is the average number of information bits obtained after sampling, which can be reliably transmitted over a radio channel. It could be improved using different techniques to control radio resources, output power, dynamic distribution of channels, adaptation of connections and different antenna diversification models. Other ways to improve spectral efficiency uplink and downlink space-division multiple access as well as techniques to acquire channel state information. This article considers two ways for improvement of spectral efficiency – increase of transmit power and obtaining and array gain. Increasing the output power will increase both the signal strength and the interference, which will result in high rate of spectral efficiency. Using linear receiving antenna array, that could “recognize” individual user equipment, the rate of interference will decrease sufficiently and will become small with decreasing the number of the antennas. The utilization of more antennas will decrease the interference if the angles of the uplink signals from the user equipment are different enough. The spectral efficiency depends on the signal-to-noise ratio of the desired signal and the degree of intercellular interference. For a mobile device, it is a slowly increasing logarithmic function of the signal-to-noise ratio. Only modest gains of spectral efficiency are possible by increasing this ratio. The practical line-of-sight channels contain random reflections and scattering. These channels are not bound to follow a particular channel model. Non line-of-sight channels can consist of various multipath components that arrive from different angles and with different phase-rotations.

излъчвана мощност спектрална ефективност интерференция пропускателна способност GSM CDMA Wi-Fi 4G LTE Spectral efficiency linear receiving antenna array interference area throughput GSM CDMA Wi-Fi 4G LTEGeorgi Dimitrov


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