For the Long Range Communication, the wireless technology used is WLAN or wireless LAN (wireless local area network, it is sometimes called as LAWN) technology. In this technology mobile users through wireless connection connect to the local area network. It is a wireless distribution method used by two or more than two devices which use an access point (which often includes) and radio waves of high frequencies to the internet. It is allowed to the users to move within the coverage area while the connection is maintained like in a small office or home The technologies specified for WLAN by 802.11 standards are CSMA/CA (carrier sense multiple access with collision avoidance) and Ethernet protocol.
For the short-range communication, the wireless technology used is Bluetooth Technology. Instead of cables and wires, this technology uses radio waves for the connection with the computer or a phone. Bluetooth watch or headset has a small computer chip with Bluetooth software which makes it easier to connect. A pair is needed when the two Bluetooth devices want to connect with each other. Devices communicate over short range or ad hoc networks which are known as piconets if using Bluetooth. Piconets can be defined as a network made by connecting devices using Bluetooth technology. One device act as master and the other devices act as slaves when the network established. Piconet connections are made both automatically and dynamically as Bluetooth enabled device leave or enter radio proximity.
There are few reasons that WLAN is used for long range and Bluetooth is used for short range. As in experiment, each terminal connects to all other terminals and for this Bluetooth is used for the short range because the bit rate capability is higher in it than in long range. Also, short range is used for the peer to peer establishment because they are more power efficient as compared to the long range.
There are three parts that can be distinguished from the above figure and these are idle, BT and BT+WLAN. The peaks in the figure show the requirement of power for the interface to power it up at each beacon. The increase in power can be seen from the transitions in the three states: from idle to the ON state of Bluetooth Interface and then to the ON state of WLAN interface. It can be concluded from the above transition that it is expensive (in case of power consumption) the activation of WLAN interface.
In above figure, the plot is the profile of measured power consumption versus the function of the number of devices (cooperating peers). In above figure, the server was programmed to send data after every 100ms and this is beacon period at the wireless access point. Data reception is shown by wide peaks whereas beacon reception is shown by narrow peaks. It can be concluded that in the measurement with three peers (cooperative scenario) it appears a wide peak after every three periods which compared to the one peer (traditional scenario) reduces over three times the power consumption over WLAN interface. A small increase can be seen on the power floor at each period caused because of power consumed by Bluetooth reception and transmission. In N peers the data exchange is synchronized data each beacon between one of its (N ¡ 1) peers and device over the Bluetooth. So the conclusion is that in mobile devices reduction gain of actual power can be achieved via the implementation of cooperative video streaming architecture and this power reduction gain with three cooperative devices reaches approx. 16%.
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