WEEK TWO
Summary of the week
In the second week of our project, we further focused on developing the core computational code for cellular network capacity, with an emphasis on channel allocation, traffic load analysis, and user capacity evaluation.
Methodology
In capacity planning for cellular networks, our calculations are divided into three main parts:
1. Channel Allocation
2. Traffic Calculation
3. User Capacity Calculation
Channel Allocation
First, we need to calculate the number of available channels per cluster, cell and sector, which is the basis for the entire cellular network planning.
1. Channels per Cluster
2. Channels per Cell
Since each cell within a cluster uses a different frequency:
3. Channels per Sector
In the case of sectorization, each cell can be further divided into multiple sectors, each using a different channel:
Traffic Calculation
Traffic is a key parameter for measuring the carrying capacity of a network. We use the Erlang B formula to calculate network capacity:
1. Traffic per User
This indicates the average Erlang traffic per user per hour.
2. Erlang B formula to calculate traffic volume
In our project, the Erlang B formula is used to calculate the relationship between network capacity and blocking probability.
The basic assumptions of the Erlang B formula are:
- A user initiates a call randomly;
- When all channels are busy, new calls are rejected outright and are not queued;
- We usually want the blocking probability to be below a certain level, say 2%.
The Erlang B formula is as follows:
- B(E, C) denotes the blocking probability;
- E denotes the call volume in Erlang;
- C denotes the number of channels.
User Capacity Calculation
After calculating the traffic capacity, we can estimate the maximum number of users that the network can support.This calculation method is the same as that for Traffic per Cluster, ensuring that the network meets the requirements of the target blocking probability.Since each user will occupy a certain amount of traffic, we can get the total number of users by dividing the total available traffic by the single-user traffic:
Problems
Although our initial implementation appeared to be on track, we discovered that the Traffic per Cluster (Erlangs) calculation yielded results that deviated from theoretical expectations. This prompted us to conduct a thorough investigation, during which we also encountered several other issues, such as debugging errors, data inconsistencies, and algorithm efficiency concerns.
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