When the audio signal is transmitted after processing and modulation, the technique will be used also jumping frequency, any carrier transmission varies continuously on a different time (and, of course, that the difference must comply with the principles of frequency planning).
The following factors are considered in the introduction of two frequency hopping technology:
1) The fading process is related to frequency range, the application of frequency hopping in the system may reduce the effects of Rayleigh fading.
2) Due to the diversity of the intervention, in areas with heavy traffic, are restricting the ability of the cell that interference caused by frequency doubling. In addition, the system is designed to meet the demands of subscribers, and is calculated by the maximum capacity of the system on the assumption that the quality of a certain number of calls is clearly reduced due to the intervention. And low diversity exact measure around the C / I value, greater system capacity. Interference call on the average value of the level of interference caused by many other calls. Thus, the intensity of the specified overlap, the more sources of intervention, the better the performance of the system.
The radio interface design for the GSM system with the slow pace of movement (SFH) technique. The difference between SFH and fast frequency hopping (FFH) is to change the frequency of the latter is faster than the modulation frequency. During the explosion sequence the entire transition period for the GSM system, the frequency transmitting has not changed. Therefore, it belongs to the slow frequency hopping, as shown in the chart above.
The GSM system allows 64 different types of frequency-hopping sequences. There are basically two of the parameters involved in the description of them: the mobile allocation index offset (MAIO) and hopping sequence number (HSN). MAIO values can be many such frequencies in the group, there are 64 different values available for HSN.
The following factors are considered in the introduction of two frequency hopping technology:
1) The fading process is related to frequency range, the application of frequency hopping in the system may reduce the effects of Rayleigh fading.
2) Due to the diversity of the intervention, in areas with heavy traffic, are restricting the ability of the cell that interference caused by frequency doubling. In addition, the system is designed to meet the demands of subscribers, and is calculated by the maximum capacity of the system on the assumption that the quality of a certain number of calls is clearly reduced due to the intervention. And low diversity exact measure around the C / I value, greater system capacity. Interference call on the average value of the level of interference caused by many other calls. Thus, the intensity of the specified overlap, the more sources of intervention, the better the performance of the system.
The radio interface design for the GSM system with the slow pace of movement (SFH) technique. The difference between SFH and fast frequency hopping (FFH) is to change the frequency of the latter is faster than the modulation frequency. During the explosion sequence the entire transition period for the GSM system, the frequency transmitting has not changed. Therefore, it belongs to the slow frequency hopping, as shown in the chart above.
The GSM system allows 64 different types of frequency-hopping sequences. There are basically two of the parameters involved in the description of them: the mobile allocation index offset (MAIO) and hopping sequence number (HSN). MAIO values can be many such frequencies in the group, there are 64 different values available for HSN.
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