The transmitted signal in a GSM system is of 200 kHz bandwidth and 8 u...
Since GSM requires 200 KHz and only 8 users can use it using TDMA, 9th user needs
another 200 KHz.
9th, 10th, 11th, 12th user can use another 200 KHz bandwidth on time share basis.
Thus for 12 user we need 400 KHz bandwidth.
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The transmitted signal in a GSM system is of 200 kHz bandwidth and 8 u...
Given information:
- The transmitted signal in a GSM system has a bandwidth of 200 kHz.
- 8 users share a common bandwidth using TDMA.
- At a given time, 12 users are talking in a cell.
Explanation:
TDMA (Time Division Multiple Access):
- In a GSM system, TDMA is used to divide the available bandwidth into multiple time slots.
- Each user is allocated a specific time slot to transmit their signals.
- Multiple users can share the same bandwidth by using different time slots.
Calculation:
- The total bandwidth available in the GSM system is 200 kHz.
- In TDMA, the bandwidth is divided into time slots, and each user is allocated a specific time slot.
- Since there are 8 users and each user is allocated a time slot, the total number of time slots is also 8.
- Therefore, the bandwidth available to each user is 200 kHz / 8 = 25 kHz.
Impact of 12 users talking simultaneously:
- At a given time, 12 users are talking in the cell.
- Since there are only 8 time slots available, not all 12 users can talk simultaneously.
- Therefore, some users will have to wait for their turn to transmit their signals.
Bandwidth received by the base station:
- The base station receives the signals transmitted by the users in the cell.
- The base station needs to receive the signals from all the users talking simultaneously.
- Since a user is allocated a bandwidth of 25 kHz, the base station needs to receive signals from all 12 users, which would require a minimum bandwidth of 12 * 25 kHz = 300 kHz.
- However, the transmitted signal in the GSM system has a bandwidth of 200 kHz.
- Therefore, the base station needs to receive a minimum total bandwidth of 300 kHz to accommodate all 12 users talking simultaneously.
Conclusion:
- The total bandwidth of the signal received by the base station of the cell will be at least 400 kHz (200 kHz + 200 kHz = 400 kHz) to accommodate all 12 users talking simultaneously.