1. Identify Traffic Requirements:
- Determine the total number of subscribers served by the BSC.
- Estimate the average voice call duration (in seconds) and the traffic intensity (calls per Erlang hour).
- Calculate the total offered traffic load in Erlangs by multiplying the number of subscribers, average call duration, and traffic intensity.
2. Determine Channel Allocation:
- Consider the number of time slots available per carrier frequency and the modulation scheme used.
- Calculate the number of available traffic channels by multiplying the number of time slots by the number of carriers.
3. Calculate Transmission Efficiency:
- Account for overhead bits, control channels, and signaling channels.
- Determine the transmission efficiency factor based on the specific configuration and technologies employed.
4. Apply Erlang B Formula:
- Use the Erlang B formula to calculate the required number of traffic channels necessary to achieve a desired Grade of Service (GoS).
- The Erlang B formula is: B = (A^n / n!)/(∑(A^i) / i!), where 'A' represents offered traffic in Erlangs, 'n' is the number of channels, and 'i' iterates from 0 to n.
5. Adjust for Multiple Carriers:
- If the BSC supports multiple carriers, adjust the traffic load and channel calculation accordingly.
6. Consider Capacity Margins:
- Add a capacity margin to account for unforeseen traffic spikes or system expansions.
7. Calculate BSC Capacity:
- The BSC capacity in Erlangs is then determined by considering the transmission efficiency, adjusted traffic load, and capacity margin.
Remember that specific BSC ZTE models and configurations may have their own capacity planning tools or guidelines, so it's important to refer to the manufacturer's documentation for accurate calculations.
Always be sure to conduct a thorough traffic analysis and take into consideration your specific deployment scenario, subscriber behavior, and network requirements to obtain the most accurate assessment of BSC ZTE capacity.