Adviser : C.H. WeiStudent : Shin-an ChanStudent ID : M9920106

Contreras, D., Castro, M., "Communications Letters, IEEE", vol15, Issue: 5, pp521-523, 2011 May

PPT:100%

Adaptive Polling Enhances Quality and

Energy Saving forMultimedia over

Bluetooth

Outline

•ABSTRACT•INTRODUCTION•TPOLL PARAMETER•EMAAA TPOLL•RESULTS•CONCLUSIONS•REFERENCES

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Abstract

In this paper we analyze the impact on performance of the lowest levels of the Bluetooth architecture through a relevant parameter known as the polling time T poll .

Specifically, we show that our algorithm can result in a significant energy saving (of 10%-20%) with respect to the Bluetooth specification.

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INTRODUCTION

Audio or video streaming, video-conference or video diffusion are typical applications whose growth is expected to be huge in the following years.

One of the drawbacks of this new computing paradigm is the lack of a revolution in batteries for them and hence.

We explore a real-time scheme that combines self-adaptation to the characteristics of the traffic transmitted with the additional benefit of energy saving.

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TPOLL PARAMETER

If the slave sends a NULL packet (no data to transmit), the master will wait for a period of time equal to T poll before sending a new POLL packet to the slave.

Much of the work aimed at the enhancement of the performance for multimedia traffic is focused on the optimum choice of the type of data packet, alternative scheduling algorithms beyond the round robin scheme or the impact of the power saving modes on performance.

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EMAAA TPOLL

The main aim of our work is to provide, through the T poll parameter, a simple, reliable and real-time mechanism of polling control that improves performance and energy saving at the same time.

In the case of real time or multimedia transmissions, the master must minimize the polling effects over traffic.

Our polling scheme is focused on reducing the total number of unnecessary NULL packets sent.

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EMAAA TPOLL

𝜶=𝟐

𝑵+𝟏

𝑁 is the number of past values taking into account to determine the new value of a given quantity on average.

𝑇 𝑝𝑜𝑙𝑙𝑡=𝜶𝑻 𝒑𝒐𝒍𝒍𝒕−𝟏

(𝒏𝒖𝒍𝒍𝒔−𝒙 )+(𝟏−𝜶 )𝑻 𝒑𝒐𝒍𝒍𝒕−𝟏

where is the number of NULL packets 𝑛𝑢𝑙𝑙𝑠sent at a previous polling cycle.

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EMAAA TPOLL

CBR the optimal value would be = 0. 𝑗𝑖𝑡𝑡𝑒𝑟Both combined give an optimal → 0. For VBR 𝑟(Poisson traffic), is a simple quantity that 𝑐tells about how different are the transmitted and received data, ideally = 1𝑐

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Results

a) For between 10 𝑁and 40, takes 𝑟the closest values to 0.

b) For multimedia traffic the optimal region requires the lowest possible value of the number of NULL packets and the closest value of to 1. 𝑐

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Results

we show the benefits of our algorithm, both in terms of energy saving and quality of traffic for CBR traffic. This is reflected in the reduction of the number of NULL packets transmitted.

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ResultsA

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- T poll=40 EMAAA T poll

CBRVBR

34%16%

14%7%

TABLE RATIO BETWEEN THE NUMBER OF NULL PACKETS AND DATA

(DH1)PACKETS.

IAT (msec)

Tpoll=40 EMAAA Tpoll Energy Saving

50100150200300

36.9mA36.2mA35.7mA35.3mA34.8mA

37.6mA35.2mA32.8mA31.1mA29.2mA

+1.7%-2.7%-9.0%

-13.7%-19.3%

Average 36.0mA 33.5mA -7.1%

CONCLUSIONS

This algorithm provides a consumption reduction up to 19%, with an average reduction of 7%.

In the case of a real transmission of audio streaming through Skype (using a 8Kbps/G.729 codec so = 200 msec and 𝐼𝐴𝑇210 bytes/packet), the energy saving would be 13%.

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REFERENCES[1] L. Meier, P. Ferrari, and L. Thiele, “Energy-efficient Bluetooth networks,"

in Technical Report 204, Computer Engineering and Networks Laboratory (TIK), ETH Zurich, Jan. 2005.

[2] J. C. Cano, J. M. Cano, E. González, C. Calafate, and P. Manzoni, “How does energy consumption impact performance in Bluetooth?” ACM SIGMETRICS Performance Evaluation Review, vol. 35, pp. 7-9, 2007.

[3] J. V. Parys, Bluetooth polling with fewer poll packets, US patent app. (2007).

[4] M. A. Morón, R. Luque, and E. Casilari, “Modeling of the transmission delay in bluetooth piconets under serial port profile," IEEE Trans. Consum. Electron., vol. 56, pp. 2080–2085, 2010.

[5] J. B. Linsky and T. R. Bourk, Method and apparatus for a dual-mode radio in a wireless communication system, US patent 7,643,463, 2010.

[6] J. Yang-ick, L. Tae-Jin, and E. D. Seop, “Differentiated scheduling for Bluetooth QoS with parameter optimization," IEICE Trans. Commun., vol. E88-B, pp. 274–281, 2005.

[7] D. Contreras, and M. Castro, “Quality-of-service adaptative algorithms on Bluetooth piconets," in Proc. 16th Conference on Concurrency and Distributed Systems, June 2008.

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Thanks For Your Listening