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  2. Frequency-hopping spread spectrum - Wikipedia

    en.wikipedia.org/wiki/Frequency-hopping_spread...

    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 .

  3. GSM Radio Frequency optimization - Wikipedia

    en.wikipedia.org/wiki/GSM_Radio_Frequency...

    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 ...

  4. Mobile Allocation Index Offset - Wikipedia

    en.wikipedia.org/wiki/Mobile_Allocation_Index_Offset

    For mobile phone technology, a mobile allocation index offset (MAIO) refers a time delay separating traffic channels.When a GSM (Global System for Mobile Communications) mobile phone is served by a cell that is hopping over a set of frequencies, the separate traffic channels hop over the allocated frequencies according to a hopping sequence number (HSN).

  5. Spread spectrum - Wikipedia

    en.wikipedia.org/wiki/Spread_spectrum

    Practical synchronous digital systems radiate electromagnetic energy on a number of narrow bands spread on the clock frequency and its harmonics, resulting in a frequency spectrum that, at certain frequencies, can exceed the regulatory limits for electromagnetic interference (e.g. those of the FCC in the United States, JEITA in Japan and the ...

  6. Code-division multiple access - Wikipedia

    en.wikipedia.org/wiki/Code-division_multiple_access

    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.

  7. Time-division multiple access - Wikipedia

    en.wikipedia.org/wiki/Time-division_multiple_access

    Most 2G cellular systems, with the notable exception of IS-95, are based on TDMA. GSM, D-AMPS, PDC, iDEN, and PHS are examples of TDMA cellular systems.. In the GSM system, the synchronization of the mobile phones is achieved by sending timing advance commands from the base station which instruct the mobile phone to transmit earlier and by how much.

  8. Chirp spread spectrum - Wikipedia

    en.wikipedia.org/wiki/Chirp_spread_spectrum

    In digital communications, chirp spread spectrum (CSS) is a spread spectrum technique that uses wideband linear frequency modulated chirp pulses to encode information. [1] A chirp is a sinusoidal signal whose frequency increases or decreases over time (often with a polynomial expression for the relationship between time and frequency).

  9. Cellular frequencies - Wikipedia

    en.wikipedia.org/wiki/Cellular_frequencies

    Many GSM phones support three bands (900/1,800/1,900 MHz or 850/1,800/1,900 MHz) or four bands (850/900/1,800/1,900 MHz), and are usually referred to as tri-band and quad-band phones, or world phones; with such a phone one can travel internationally and use the same handset. This portability is not as extensive with IS-95 phones, however, as IS ...

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