Cross-layer optimization: Difference between revisions

Revision as of 01:15, 1 March 2016

Revision as of 01:16, 1 March 2016

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Communication systems that need to operate over media with non stationary background noise may benefit from having a close coordination between the [[Medium access control|MAC]] layer (which is responsible for scheduling transmissions) and the [[Physical layer|PHY]] layer (which manages actual transmission and reception of data over the media), as for e.g.,

<ref>S. Shabdanov, P. Mitran, C. Rosenberg,

[http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6151784&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6151784 "Cross-layerLayer optimizationOptimization inUsing wirelessAdvanced Physical Layer Techniques in multihopWireless networksMesh Networks", in IEEE Transactions on Wireless Communications]</ref>

In some communications channels (for example, in power lines), noise may be non-stationary and might vary synchronously with the 50 or 60&nbsp;Hz [[AC current]] cycle. In scenarios like this, overall system performance can be improved if the MAC can get information from the PHY regarding when and how the noise level is changing, so that the MAC can schedule transmission during the periods of time in which noise levels are lower.