The working characteristics of the wire harness are studied. The key problem is to solve the state probability distribution of the wire harness. The basic mathematical model of the wire harness is the process of increase and decrease. It is assumed that: ① In a very short time △t, the wire harness can only be transferred from the current state to the adjacent state or there will be no state change. For example, the number of calls in the wire harness can be regarded as the state of the wire harness. If there are n calls, the current status is e n. Its adjacent state is En- 1 or En+ 1. (2) The conditional transition probability that the current state of the harness is En, and it also transitions to the state En+ 1 after △t is λn△t+0(△t), where λn is the call strength in the En state. 0(△t) means that the higher order of △t is infinitesimal. ③ The current state of the harness is En, and it takes △t time to switch to the state En- 1, and the conditional transition probability is μn△t+0(t), where μn is the call ending strength in the En state.

Based on the probability distribution of the state of the wire harness in the process of addition and subtraction, a series of problems related to the carrying capacity of the wire harness can be solved.

I. Harness utilization

Refers to the number of service devices that can be used by any load source in the load source group. In the partial utilization of wiring harness, it is impossible for any load source to use the full capacity of the wiring harness, but only a part of the equipment can be used. If k represents the utilization rate of the wiring harness and v represents the capacity of the wiring harness, then there is V ≥ K. When V=K, the wiring harness is completely available, and the availability K is limited by the structure of the wiring device.

Second, the harness utilization rate

Refers to the use efficiency of wire harness. It is numerically equal to the average completed traffic intensity of each line. η is used to indicate the utilization ratio of wire harness, including

η

Where A0 and A are the completed traffic intensity and incoming traffic intensity of the wire harness respectively, V is the capacity of the wire harness, and E is the loss probability of the wire harness.

One of the tasks of the telecom system designer is to build a high-utilization network under the premise of a certain quality of service, that is, to build the most economical harness structure and application mode. The utilization ratio of wire harness is interrelated and restricted with the load, capacity, structure and service quality of wire harness. Take the loss harness as an example. Under certain call loss conditions, the larger the capacity of the harness, the higher the utilization rate of the harness. For a certain capacity of wire harness, the greater the call loss, the higher the utilization rate of wire harness.

Third, the fittings are overloaded.

Refers to the situation that the wire harness runs under a load greater than the rated load. In the actual telecommunication system, the wire harness is sometimes overloaded. Overload will reduce the service quality of the wiring harness. The correct design should be, when

When the overload is within the allowable range, the decline of service quality should be limited to a given range. In order to meet this requirement, the utilization rate of wire harness can not be improved indefinitely. The harness with high utilization rate is very sensitive to overload.