Channel Capacity - Essay Example

Channel Capacity is the data transmission rate over a given path or communication or channel (Stallings, 2006). Any given system of communication has a maximum information rate C or channel capacity. The focus is mainly on how fast one can transmit information or data over a communication channel. If a source transmits r messages in a second, and the message entropy is H bits at a message, the rate of information (R) will be R=rH. However, there are several factors that affect channel capacity(Stallings, 2006). These include bandwidth, noise, error rate, and data rate.

Noise includes intermodulation, thermal, impulse, and crosstalk. Noise is mainly expected at the link; hence the signal power at the receiver has to be larger as compared to the power added noise to the signal in the path of transmission(Stallings, 2006). Data rate involves the bit number that a system is capable of transmitting in a time unit. The data rate is constrained by bandwidth, availability of impairments, and the acceptable error rate. The bandwidth that is effective is the band within which signal energy is mostly concentrated. A channel is able to accommodate a limited frequency band. If in bandwidth that is effective, the input signal is larger than the system transmission bandwidth, the signal at the output will be highly distorted(Stallings, 2006). The bandwidth of the signal should match the bandwidth being supported by the communication channel. The error rate can be seen as the rate whereby errors can occur. An error is a reception of 1 when 0 was channeled or a reception of 0 when 1 was channeled(Stallings, 2006).

The main factor characterizing channel capacity is the bandwidth. A great bandwidth of signal results in great information-carrying capacity. While designing a facility for communication one should consider signal bandwidth, digital information data rate, noise amount, and acceptable error rate.