Без темы
<<  Life expectancy by NS-SEC Lincolns Presidency An Online Professional Development Seminar  >>
Life-Add: A novel WiFi design with battery life, throughput and
Life-Add: A novel WiFi design with battery life, throughput and
Background
Background
Existing Solutions to Prolong Lifetime
Existing Solutions to Prolong Lifetime
IEEE 802
IEEE 802
Can we do better
Can we do better
Contents
Contents
Life-Add: Smartphone energy model
Life-Add: Smartphone energy model
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Life-Add: Sleep/Wake + Channel Contention
Uplink A new renewal process model: each cycle is an i.i.d. period
Uplink A new renewal process model: each cycle is an i.i.d. period
Life-Add vs IEEE 802
Life-Add vs IEEE 802
Life-Add: Downlink
Life-Add: Downlink
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Problem formulation
Problem formulation
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Life-Add: Single AP
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Life-Add: general multiple APs
Summary
Summary
Tasks to do…
Tasks to do…
Thank you
Thank you

Презентация: «Life-Add: A novel WiFi design with battery life, throughput and fairness improvement». Автор: Yin Sun. Файл: «Life-Add: A novel WiFi design with battery life, throughput and fairness improvement.pptx». Размер zip-архива: 1185 КБ.

Life-Add: A novel WiFi design with battery life, throughput and fairness improvement

содержание презентации «Life-Add: A novel WiFi design with battery life, throughput and fairness improvement.pptx»
СлайдТекст
1 Life-Add: A novel WiFi design with battery life, throughput and

Life-Add: A novel WiFi design with battery life, throughput and

fairness improvement

WiOpt 2013

Shengbo Chen*, Tarun Bansal*, Yin Sun*, Prasun Sinha and Ness B. Shroff Dept. ECE & CSE, The Ohio State University

2 Background

Background

Battery life is a serious problem for most smartphone users WiFi, 4G LTE, GPS, Bluetooth, screen, CPU, ... Web browsing via WiFi Test results in April 2013 by Battery life < 11 hours for most popular smartphones

iPhone 5 802.11n

Samsung Galaxy S 4 802.11ac

HTC One 802.11ac

3 Existing Solutions to Prolong Lifetime

Existing Solutions to Prolong Lifetime

Mobile Charging? Additional equipment Solar charger portable battery wireless charger Reduce power when sensing Lower hardware clock-rate [E-MiLi, Mobicom 11] Broadcom SoC Solution 802.11 ac Used in HTC One and Samsung Galaxy S 4 Test: 7.8 hours by Trade bandwidth/throughput for power reduction Cannot have both benefits

4 IEEE 802

IEEE 802

11 Standard Evolution

Physical layer Significant evolutions towards high throughput MAC CSMA/CA and its enhancements QoS, security, frame aggregation, block ACK

WLAN

802.11- 1997 2 Mbps, DSSS, FHSS

802.11b 11 Mbps, CCK, DSSS

802.11n 600 Mbps with 4x4 MIMO, 20/40 MHz BW, 2.4 or 5 GHz

802.11a 54 Mbps, OFDM, 5 GHz

802.11p 27 Mbps,10 MHz BW, 5.9 GHz

802.11af TVWS

TV White Spaces

Wireless Access for Vehicular Environment

802.11g 54 Mbps, OFDM, 2.4 GHz

802.11ac 256QAM 160MHz

Wireless Gigabit, <6 GHz

802.11ad

Wireless Gigabit, 60 GHz

5 Can we do better

Can we do better

Life-Add: An innovative MAC design Battery Lifetime Avoid unnecessary sensing Throughput Reduce collisions and starvations Fairness Near-far effect

B

L

E

T

I

F

E

I

M

E

N

R

F

A

I

N

E

E

S

S

F

I

U

G

H

P

U

T

T

R

O

T

H

6 Contents

Contents

Background Life-Add: An innovative MAC design Simulation Results Summary

7 Life-Add: Smartphone energy model

Life-Add: Smartphone energy model

Power source: Strong: Wall power, portable battery Weak: Solar charger Other components 4G LTE, CPU, screen, … WiFi chip ON: Transmit/receive/sensing High power consumption OFF: Sleep Very low power consumption Too much sensing means a significant waste of energy Sleep/wake (asynchronous)

8 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

Device 1

Device 1

Device 2

Device 2

AP

AP

ACK

9 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

Device 1 wakes up earlier and senses the channel

Device 1

Device 1

Device 2

Device 2

AP

AP

ACK

10 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

Device 1 transmits, Device 2 goes back to sleep

Device 1

Device 1

Device 2

Device 2

AP

AP

Data

ACK

11 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

AP replies an ACK to Device 1. Cycle 1 completes.

Device 1

Device 1

Device 2

Device 2

AP

AP

Cycle 1

Data

ACK

ACK

12 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

Devices 1 and 2 wake up at almost the same time

Device 1

Device 1

Device 2

Device 2

AP

AP

Cycle 1

Data

ACK

ACK

13 Life-Add: Sleep/Wake + Channel Contention

Life-Add: Sleep/Wake + Channel Contention

Uplink

A collision occurs, followed by a timeout. Cycle 2 completes.

Device 1

Device 1

Device 2

Device 2

AP

AP

Cycle 2

Cycle 1

Data

Data

Data

ACK

ACK

14 Uplink A new renewal process model: each cycle is an i.i.d. period

Uplink A new renewal process model: each cycle is an i.i.d. period

Requires 2 assumptions: Exponential distributed sleep period: Memoryless (independent from last cycle) Tdata + TACK? Tcollision + Ttimeout (only assumed in analysis, not in simulations)

Life-Add: Sleep/Wake + Channel Contention

Device 1

Device 1

Device 2

Device 2

AP

AP

Cycle 2

Cycle 1

Data

Data

Data

Data

ACK

ACK

15 Life-Add vs IEEE 802

Life-Add vs IEEE 802

11

Life-Add IEEE 802.11 Sleep backoff vs sensing backoff (save energy) Renewal process vs 2D Markov chain [Bianchi 2000] (simplify optimization)

Device 1

Device 2

AP

Device 1

Device 2

AP

Cycle 2

Cycle 1

Data

Data

Data

Data

ACK

ACK

Data

Data

Data

Data

ACK

ACK

16 Life-Add: Downlink

Life-Add: Downlink

Still a renewal process Uplink: sleep + data + overhead (ACK/collision/timeout) Downlink: sleep + data + overhead (ACK/Ps-poll/collision/timeout) Additional Ps-poll packet as part of overhead Can be modeled together

A short Ps-poll packet is used to contend for the channel

Device 1

Device 2

AP

Cycle 2

Cycle 1

Ps-poll

Ps-poll

ACK

ACK

Ps-poll

Data

Data

Beacon

17 Life-Add: Single AP

Life-Add: Single AP

Proportional-fair Utility Maximization max ? log E{Throughput of Device i} s.t.

E{Battery Life of Device i} ? Tmin,i

18 Life-Add: Single AP

Life-Add: Single AP

Proportional-fair Utility Maximization max ? log E{Throughput of Device i} s.t. Maximal device-ON probability: bi Variables: average sleep period 1/Ri

Pr{Device i’s RF is ON}? bi

19 Life-Add: Single AP

Life-Add: Single AP

Proportional-fair Utility Maximization max ? log E{Throughput of Device i} s.t. Maximal device-ON probability: bi Variables: average sleep period 1/Ri Non-convex Asynchronous network with collisions Channel access probabilities of the devices are coupled We propose a solution: Life-Add Theorem: Asymptotically optimal, as Tsensing /(Tdata + TACK)?0 E.g., 802.11b: Tsensing= 4us, Tdata + TACK=511us~1573us

Pr{Device i’s RF is ON}? bi

20 Problem formulation

Problem formulation

where , is a scaling constant is the transmission success probability is the device-ON probability Proof idea: Problem structure, KKT necessary conditions Upper and lower bounds converge to the same value

21 Life-Add: Single AP

Life-Add: Single AP

Implementation procedure: Each device reports bi to the AP The AP computes , and broadcast them to the devices If , If , Device n uses and to compute Use to generate the sleeping period Low complexity, easy to implement

Pr{Device i’s RF is ON}? bi

22 Life-Add: Single AP

Life-Add: Single AP

NS-3 simulation for a homogeneous scenario Red curve: simulated performance with no approximation Blue point: closed form solution of Life-Add Observation: Life-Add is near optimal The renewal process model is reasonably accurate

23 Life-Add: general multiple APs

Life-Add: general multiple APs

Too complicated interference model Global optimization is very difficult Near-far effect Device 1 can access the channel all the time Device 2 is in starvation Hidden terminal problem Two devices cannot sense each other and cause collisions

24 Life-Add: general multiple APs

Life-Add: general multiple APs

Near-far effect Node collaboration Device 1 computes the two values of average sleep period suggested by AP 1 and AP 2 Device 1 chooses the longest average sleep period to reduce collisions with Device 2, which is vulnerable To care for the vulnerable

25 Life-Add: general multiple APs

Life-Add: general multiple APs

Hidden terminal problem Increase average sleep period after a collision Reset average sleep period after a successful transmission Similar idea to 802.11 MAC

26 Life-Add: general multiple APs

Life-Add: general multiple APs

Implementation procedure: Each device reports bi to nearby APs Each AP computes and broadcasts and If , If , Device n uses and to compute suggested by nearby APs Choose to use the smallest value Reduce at collision, reset after receiving ACK Use to generate the sleeping period

27 Life-Add: general multiple APs

Life-Add: general multiple APs

NS-3 simulation results: Uplink: 4 APs, 30 smartphones, randomly located in a 500?500 m field, UDP saturation bi = 1 ? no lifetime (power-ON prob.) constraints 1/3 with battery, 1/3 with battery + solar panel, 1/3 to wall power Battery level: uniform distribution within 200~1000 mAh Lifetime and throughput benefits

28 Life-Add: general multiple APs

Life-Add: general multiple APs

NS-3 simulation results: Per-device performance: Battery life improvement for all 5 devices Significant throughput increase for the low-rate device

29 Life-Add: general multiple APs

Life-Add: general multiple APs

Average performance gain Battery Life: Sleep/Wake Throughput: Node collaboration (reduce collisions and starvations) Parameter optimization Fairness: Node collaboration (to care for the vulnerable) Proportional-fair utility

30 Life-Add: general multiple APs

Life-Add: general multiple APs

Coexisting with IEEE 802.11 AP 1,2 and their users upgrade from IEEE 802.11 to Life-Add Battery life Longer if you use Life-Add Throughput Higher no matter you use Life-Add or not, due to less collisions

31 Summary

Summary

A novel renewal process model for energy efficient WiFi design Proportional-fair utility maximization problem Non-convex Life-Add MAC design Near optimal for single AP cases Alleviate “near-far effect” and “hidden terminal problem” in general cases Easy to implement Ns-3 simulations Battery life, throughput, and fairness improvement Coexists harmoniously with IEEE 802.11 Not just WiFi: Last-hop decentralized access Internet of Things, Military,… US patent filed

32 Tasks to do…

Tasks to do…

More simulations for joint uplink and downlink Practical traffics Web browsing, video streaming, email, searching Hardware testing

33 Thank you

Thank you

B

E

T

L

I

F

I

M

E

E

N

R

F

A

I

N

E

E

S

S

F

I

U

P

T

G

H

U

T

T

H

R

O

«Life-Add: A novel WiFi design with battery life, throughput and fairness improvement»
http://900igr.net/prezentacija/anglijskij-jazyk/life-add-a-novel-wifi-design-with-battery-life-throughput-and-fairness-improvement-151200.html
cсылка на страницу
Урок

Английский язык

29 тем
Слайды
900igr.net > Презентации по английскому языку > Без темы > Life-Add: A novel WiFi design with battery life, throughput and fairness improvement