the reason is certainly related to the fact that the speech is put in frame of 20ms. And when the GSM was invented, 20ms could be encoded/compressed/etc. into 4x0.577 ms.
20ms => 4x0.577ms = 2.3ms
each 20ms, one user needs 2.3ms.
So during 20ms on the air, only 8 calls can be multiplexed.
20/2.3 = 8.7
The remaining is used for in band signalling (sacch).
8 time slots
1 frame = 8 timeslots (0 to 7) of approximately 577 μs duration with 156.25 bits per timeslot. The duration of 1 frame = 577 μs X 8 = 4615 μs = 4.615 ms ...Engr. Adakole Ogbole
4
8
8
national commercials bid on timeslots use a slogan
Differing Characteristics :-In E1 Encoding/Decoding is followed by A-Lawwhile in T1 Encoding/Decoding is followed by µ-Law.In E1 - 13 Number of Segments in Characteristicswhile in T1 - 15 Number of Segments in Characteristics.In E1 - 32 Number of Timeslots / PCM Framewhile in T1 - 24Number of Timeslots / PCM Frame.In E1 - 8 x 32 = 256 number of bits / PCM Frame while in T1 - 8 x 24 + 1* = 193 number of bits / PCM Frame. (* Signifies an additional bit).In E1 - (125µs x 8)/256 = approx 3.9µs is the length of an 8-bit Timeslot while in T1 - (125µs x 8)/193 = approx 5.2µs is the length of an 8-bit Timeslot.In E1 - 8000/s x 256 bits = 2048kbit/s is the Bit Rate of Time-Division Multiplexed Signal while in T1 - 8000/s x 193 bits = 1544kbit/s is the Bit Rate of Time-Division Multiplexed Signal.
yes you can do it it's simple
no
Frequency Hopping is an old technique introduced firstly in military transmission system to ensure the secrecy of communications and combat jamming. Frequency Hopping is mechanism in which the system changes the frequency (uplink and downlink) during transmission at regular intervals. It allows the RF channel used for signaling channel (SDCCH) timeslot or traffic channel (TCH) timeslots, to change frequency every TDMA frame (4.615 ms). The frequency is changed on a per burst basis, which means that all the bits in a burst are transmitted in the same frequency.
What is the gsm?
The answer will depend on whether the 8 inches refers to the radius or the diameter of the frame.