Ads
related to: frequency hopping in gsm business plan diagram pdf download
Search results
Results From The WOW.Com Content Network
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver .
GSM radio frequency optimization (GSM RF optimisation) is the optimization of GSM radio frequencies. GSM networks consist of different cells and each cell transmit signals to and receive signals from the mobile station, for proper working of base station many parameters are defined before functioning the base station such as the coverage area of a cell depends on different factors including ...
Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system. In the FDMA and TDMA systems, frequency planning is an important consideration. The frequencies used in different cells must be planned carefully to ensure signals from different cells do not interfere with each other.
This is the case in both GSM and IS-136 for example. Exceptions to this include the DECT and Personal Handy-phone System (PHS) micro-cellular systems, UMTS-TDD UMTS variant, and China's TD-SCDMA, which use time-division duplexing, where different time slots are allocated for the base station and handsets on the same frequency.
The Radio Frequency Block sends and receives signals to/from portable devices (via the air interface) and converts between digital data and antenna signal. Some of the main functions are D/A and A/D conversion, up/down conversion, carrier selection, linear power amplification, diversity transmit and receive, RF combining and RF filtering.
The third phase of the RF planning process incorporates further detail into the RF plan. This stage includes items such as collecting drive data to be used to tune or calibrate the propagation prediction model, predicting the available data throughout each site, fine-tuning of parameter settings (e.g. antenna orientation, downtilting, frequency ...