Lecture16-17-Feb26-Mar16-04

Lecture16 17 feb26 mar16 04

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MAC Protocols In Sensor Networks Multiple Access Control (MAC) Protocols MAC allows multiple users to share a common channel. Conflict-free protocols ensure successful transmission. Channel can be allocated to users statically or dynamically. Only static conflict-free protocols are used in cellular mobile communications - Frequency Division Multiple Access (FDMA): provides a fraction of the frequency range to each user for all the time - Time Division Multiple Access (TDMA) : The entire frequency band is allocated to a single user for a fraction of time - Code Division Multiple Access (CDMA) : provides every user a portion of bandwidth for a fraction of time Contention based protocols must prescribe ways to resolve conflicts - Static Conflict Resolution: Carrier Sense Multiple Access (CSMA) - Dynamic Conflict Resolution: the Ethernet, which keeps track of various system parameters, ordering the users accordingly Frequency Division Multiple Access (FDMA) Channels are assigned to the user for the duration of a call. No other user can access the channel during that time. When call terminates, the same channel can be re-assigned to another user FDMA is used in nearly all first generation mobile communication systems, like AMPS (30 KHz channels) Number of channels required to support a user population depends on the average number of calls generated, average duration of a call and the required quality of service (e.g. percen...
View Full Document

This note was uploaded on 08/25/2011 for the course EEL 5937 taught by Professor Staff during the Spring '08 term at University of Central Florida.

Ask a homework question - tutors are online