Energy-efficient on-the-fly Wi-Fi hotspot using mobile devices

1. A computer-implemented process for utilizing one or more mobile devices to provide Internet access to one or more client computers, comprising:

using the client computers to perform the following process actions:

designating one of the client computers as a Wi-Fi access point (AP); and

using the Wi-Fi AP to implement a reverse-infrastructure Wi-Fi mode which tethers available mobile devices and other client computers to the Wi-Fi AP.

2. The process of claim 1 , wherein the process action of designating one of the client computers as a Wi-Fi AP comprises an action of implementing a consensus-based protocol on each of the client computers to select a client computer to be designated as the Wi-Fi AP.

3. The process of claim 1 , wherein the available mobile devices comprise mobile devices that are turned on, and are idle.

4. The process of claim 1 , wherein,

the Wi-Fi AP establishes an on-the-fly Wi-Fi hotspot which generates a Wi-Fi wireless local area network (WLAN),

the available mobile devices and other client computers are tethered to the Wi-Fi AP via the WLAN, and

the process action of using the Wi-Fi AP to implement a reverse-infrastructure Wi-Fi mode which tethers available mobile devices and other client computers to the Wi-Fi AP comprises the actions of:

each available mobile device and each other client computer joining the WLAN by associating with the Wi-Fi AP as a Wi-Fi client;

computing an optimal beacon interval (b optimal ); and

periodically transmitting at b optimal a beacon over the WLAN to each available mobile device and each other client computer.

5. The process of claim 4 , wherein the optimal beacon interval (b optimal ) is given by the equation

b

optimal

=

2

⁢

D

avg

⁢

α

θ

,

wherein a think time period comprises a period of time between a first webpage being downloaded to a requesting client computer and the requesting client computer requesting a second webpage, D avg is an average think time period, α is a wake-up energy cost for a given beacon reception by a given tethered mobile device, and θ is a base power consumed by a given tethered mobile device excluding the power consumed by a Wi-Fi WLAN radio and wireless wide area network radio within said given tethered mobile device.

6. The process of claim 4 , wherein the process action of using the Wi-Fi AP to implement a reverse-infrastructure Wi-Fi mode which tethers available mobile devices and other client computers to the Wi-Fi AP further comprises the actions of:

whenever a new mobile device or client computer becomes available, said new mobile device or client computer joining the WLAN by associating with the Wi-Fi AP as a Wi-Fi client; and

whenever an existing mobile device or client computer that is currently a member of the WLAN becomes unavailable, said existing mobile device or client computer leaving the WLAN by disassociating with the Wi-Fi AP.

7. The process of claim 4 , wherein each available mobile device is configured to operate in Wi-Fi adaptive power save mode.

8. The process of claim 4 , wherein the process action of designating one of the client computers as a Wi-Fi AP comprises the actions of:

whenever the Wi-Fi AP leaves the WLAN, detecting an absence of the beacon on the client computers remaining on the WLAN; and

implementing a leader election procedure on said remaining client computers to designate another client computer as the Wi-Fi AP.

9. The process of claim 1 , wherein,

the Wi-Fi AP establishes an on-the-fly Wi-Fi hotspot which generates a Wi-Fi wireless local area network (WLAN),

the available mobile devices and other client computers are tethered to the Wi-Fi AP via the WLAN,

a session comprises a period of time during which a given client computer is accessing a plurality of webpages which are located on the Internet,

an idle time period comprises a period of time between successive sessions, and

the process action of using the Wi-Fi AP to implement a reverse-infrastructure Wi-Fi mode which tethers available mobile devices and other client computers to the Wi-Fi AP comprises the actions of:

each available mobile device and each other client computer joining the WLAN by associating with the Wi-Fi AP as a Wi-Fi client;

computing a first optimal beacon interval (b optimal );

computing a second optimal beacon interval (b optimal — session );

during a given session, periodically transmitting at b optimal a beacon over the WLAN to each available mobile device and each other client computer; and

during the idle time period between successive sessions, periodically transmitting at b optimal — session the beacon over the WLAN to each available mobile device and each other client computer.

10. The process of claim 9 , wherein,

the first optimal beacon interval (b optimal ) is given by the equation

b

optimal

=

2

⁢

D

avg

⁢

α

θ

,

and

the second optimal beacon interval (b optimal — session ) is given by the equation

b

optimal_session

=

2

⁢

I

avg

⁢

α

θ

,

wherein,

a think time period comprises a period of time between a first webpage being downloaded to a requesting client computer and the requesting client computer requesting a second webpage, D avg is an average think time period, I avg is an average idle time period, α is a wake-up energy cost for a given beacon reception by a given tethered mobile device, and θ is a base power consumed by a given tethered mobile device excluding the power consumed by a Wi-Fi WLAN radio and wireless wide area network radio within said given tethered mobile device.

11. The process of claim 1 , wherein the mobile devices comprise smartphones.

12. A computer-implemented process for utilizing a mobile device to provide Internet access to a client computer, comprising the following process actions:

designating the client computer as a Wi-Fi access point (AP); and

whenever the mobile device is located in the vicinity of the Wi-Fi AP, and is turned on, and is idle, using the Wi-Fi AP to implement a reverse-infrastructure Wi-Fi mode which tethers the mobile device to the Wi-Fi AP, wherein,

the Wi-Fi AP establishes an on-the-fly Wi-Fi hotspot which generates a Wi-Fi wireless local area network (WLAN),

the mobile device is tethered to the Wi-Fi AP via the WLAN, and

said implementation comprises:

the mobile device joining the WLAN by associating with the Wi-Fi AP as a Wi-Fi client;

computing an optimal beacon interval b optimal which is given by the equation

b

optimal

=

2

⁢

D

avg

⁢

α

θ

,

wherein a think time period comprises a period of time between a first webpage being downloaded to the Wi-Fi AP and the Wi-Fi AP requesting a second webpage, D avg is an average think time period, α is a wake-up energy cost for a given beacon reception by the mobile device, and θ is a base power consumed by the mobile device excluding the power consumed by a Wi-Fi WLAN radio and wireless wide area network radio within the mobile device; and

periodically transmitting at b optimal a beacon over the WLAN to the mobile device.