I am new to RF Communication . Can anyone help me in understanding the term 'Channel' regarding it . What type of Multiplexing do XBee Modules involve .
In communications I believe the term channel can refer to either the pyhsical medium over which the transmission takes place (for RF this would be the air) or it can refer to one of several data streams that are being multiplexed over the same pyhsical channel.
XBee is a brand of wireless modules, they have a range of products incorporating zigbee, wi-fi and their own proprietary protocols. Within each of these standards there are several different methods used to multiplex the data channels. You need to be more specific about which XBee product you are refering to.
Edit So you've clarified that it's the XBee S1 that's of interest to you. I think this uses the 802.15.4 standard. Which largely uses code division multiple access (CDMA) as it's method of separating channels. So in the same way as AM radio separates the channels by modulating a carrier frequency (the channel you select on your radio) by the amplitude of the signal of interest, CDMA achieves the channel separation by modulating a pseudo random code with the code of interest (I think it's only really done in digital systems). There is a bit more to it though as the standard uses a direct sequence spread spectrum technique to transmit with. This is a bit more complicated to get your head around; basically it's a wideband method that just looks like noise to anything that isn't tuned into the precise DSSS sequence.