CC1101: Range of this RF Chip, How to change communication frequency & transmission power?

This is covered in the datasheet: http://www.ti.com/lit/ds/symlink/cc1101.pdf

Chapter 21 for setting the frequency, chapter 24 for output power programming. 

Is this chip have node addressing kind addressing technique? i mean if i have 4 transmitters and 1 receiver , my receiver will receive all 4 data from 4 transmitters right? then how will i know that which data from which transmitter?   or am i getting wrong that this is switch on radio like anyone can send data to receiver without needed of pair (like Bluetooth and wifi), there is no need of pair right?

my application is to transmit the Voice over RF . 

See "15.3.1 Address Filtering" in the datasheet. 

This is a transceiver meaning that this chip only covers the physical layer. Pairing etc is implemented on a higher layer meaning that using this chip you can freely implement (or not) what you want.  

I note that you rejected my suggested answer without providing a reason why? 

Read the question and after that read your answer,  you will get reason of my rejection.

Then maybe you should rephrase the question? 

Node addressing and pairing is not part of the phy layer and this chip only covers phy. 

i have also asked the Range of this chip, which we can fairly count as hardware question. however i do not know about the chip have functionality for node addressing so just asked for that, i do not want detailed explanation.

Range is a function of a number of parameters. If you use http://www.ti.com/tool/RF-RANGE-ESTIMATOR and find the setting that is closest to the CC1101 datasheet to be used as input. 

i believe every RF (wireless communication chip) have min to max distance range of communication, in our language we call it Line of sight, and there is definitely every rf company have tested it, now it is matter of lack of documentation of the chip manufacturer.