Power Control - Benefits

Benefits

Increasing transmit power on a communication link has numerous benefits:

  • In general, for any particular set of channel conditions, a higher transmit power translates into a higher signal power at the receiver. Having a higher signal-to-noise ratio (SNR) at the receiver reduces the bit error rate of a digital communication link.
  • A higher SNR can also allow a system that uses link adaptation to transmit at a higher data rate, resulting in a system with greater spectral efficiency.
  • In a wireless fading channel, using higher transmit power provides more protection against a signal fade. In a cellular network, for example, this results in a lower dropped call probability.

Using a higher transmit power, however, has the following drawbacks:

  • Overall power consumption in the transmitting device is higher. This is of particular concern in mobile devices, where battery life is reduced correspondingly.
  • Interference to other users in the same frequency band is increased. In cellular spread-spectrum systems such as CDMA, where users share a single frequency and are only separated by different spreading codes, the number of users that a cell can support as well as the size of the cell are typically limited by the amount of interference present in the cell; increased interference therefore results in decreased cell capacity and size. Even in FDMA systems such as GSM where each user in a cell uses a different frequency, interference is still present between different cells and reduces the amount of frequency reuse the network can support. In wireline networks such as DSL, lines from many subscriber homes are often bundled together, and interference between signals on different lines manifests itself as crosstalk and reduces the achievable data rate to each home.

Typically, there is no simple answer to the problem of power control, and a good algorithm must strike a balance between the benefits and drawbacks associated with targeting a particular transmit power based on the performance criteria of most importance to the designer.

Read more about this topic:  Power Control

Famous quotes containing the word benefits:

    It is with benefits as with injuries in this respect, that we do not so much weigh the accidental good or evil they do us, as that which they were designed to do us.—That is, we consider no part of them so much as their intention.
    Laurence Sterne (1713–1768)

    I do seriously believe that if we can measure among the States the benefits resulting from the preservation of the Union, the rebellious States have the larger share. It destroyed an institution that was their destruction. It opened the way for a commercial life that, if they will only embrace it and face the light, means to them a development that shall rival the best attainments of the greatest of our States.
    Benjamin Harrison (1833–1901)

    One of your biggest jobs as a parent of multiples is no bigger than simply talking to your children individually and requiring that they respond to you individually as well. The benefits of this kind of communication can be enormous, in terms of the relationship you develop with each child, in terms of their language development, and eventually in terms of their sense of individuality, too.
    Pamela Patrick Novotny (20th century)