2012 6th International Conference on Sciences of Electronics, Technologies of Information and Telecommunications (SETIT)
Studying the Throughput Efficiency of JPEG Image Transmission over Mobile IEEE 802.15.1 Network Using EDR Packets M. A. M. El-Bendary, M. El-Tokhy
F. Shawki, and F. E. Abd-El-Samie
Dept. of Electronics Technology, Faculty of Industrial Education, Helwan University. Cairo, Egypt
[email protected]
Dept. of Electronics Technology, Faculty of Industrial Education, Helwan University. Cairo, Egypt
[email protected] one piconet. A master of any piconet may be a slave in other one. Up to 10 piconets can exist within Bluetooth range [2].
Abstract—Throughput is one of the most important factors in wireless communication. This paper studies the throughput efficiency of Bluetooth network using Enhanced Data Rate (EDR) packets. This paper, proposes improving the throughput efficiency of JPEG image transmission over mobile Bluetooth network using Enhanced Data Rate (EDR) packets. This paper uses the 2DH3 and proposed 2DM3 EDR Asynchronous Connectionless (ACL) packets. This paper presents a proposed using efficient error control schemes to improve the throughput of Bluetooth systems. A comparison study between different propositions is held in the paper to choose an efficient case over mobile Bluetooth network. The simulation experiments are carried over correlated Rayleigh fading channel. Our experiments reveal that the proposed convolutional code with constraint length K=3 and 7 improves the throughput efficiency of JPEG image at low SNR values. In our simulation results show that the convolutional codes are good over correlated fading channel more than the traditional Bluetooth error correction scheme for EDR Bluetooth packets. At higher SNR values (SNR>28dB) the standard uncoded 2DH3 packets gives a good throughput. Finally, using convolutional code with different K values improves the throughput over mobile Bluetooth network.
Bluetooth operates in the unlicensed 2.4 GHz ISM (Industrial Scientific Medical) frequency band, which is also utilized by various wireless and radio technologies, such as IEEE 802.11b/g standard, IEEE 802.15.4 standard [3], cordless telephones, and even microwave ovens. Bluetooth employs the Frequency Hopping Spread Spectrum (FHSS) technique to mitigate the interferences caused by other wireless services, coexisting in the 2.4 GHz frequency band. The Bluetooth technology presents the industrial specifications of wireless personal area networks (PANs), where it provides wireless media to connect and exchange information between devices. Bluetooth employs variable-size packets. These packets occupy different number of time-slots up to a maximum of five slots; each time-slot length is 625µs. Bluetooth v. 2.1 has brought EDR packets types. These EDR packets support gross air rates of 2 Mbps and 3 Mbps through Л/4-DQPSK and 8DPSK modulation respectively [3]. There are many of papers studied using Bluetooth in hospitals environments, control automations, and industrial application. All previous proposed applications may need transmission colored images. In this paper, we try to study the transmission of colored images over a mobile Bluetooth network and trying to improve the performance of colored image transmission. In our simulation, we use different techniques, such as different error control techniques. The transmission of image simulation is carried out using one of EDR Bluetooth packets [2DH3]. 2DH3 packet is one of ACL link packets. This packet carries 3000 bits Payload (PL) uncoded data. In this paper, we proposed using default 2DH3 packet and proposed packets through using error control codes schemes, such as convolutional code and Hamming code [4].
Keywords: Mobile Bluetooth terminals, Fading channels, Jackes' model, and error correction techniques, Convolutional Codes.
I. INTRODUCTION Bluetooth is a wireless protocol utilizing short-range communications technology transmitting data over short distance from fixed and/or mobile devices to establishing wireless personal area networks (WPANs). Bluetooth provides a way to connect and exchange information between devices such as mobile phones, telephones, laptops, personal computers, printers, and digital cameras. Bluetooth system is efficient more than infrared (IR) wireless connecting. IR is a line of sight technology and it supports one to one connection. [1].
The paper is organized as follows. In section II, the proposed modifications are presented. In section III, Image fragmentation & transmission is discussed. In section IV, the simulation assumptions are given. The simulation results are introduced in section V. Finally, the paper is concluded in section VI.
It operates within distance of 10-100 meters. The structure of stations in different Bluetooth versions follows a piconet structure. Each piconet comprises up to seven Bluetooth devices working as slaves (S) and only one Bluetooth device as a master (M) station. A slave can be a member in more than
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II. PROPOSED MODIFICATIONS The transmission of multimedia contents over unreliable data links has become of paramount importance. This type of transmission must reconcile the high data rates involved in multimedia contents and the noisy nature of the channels, be it wireless or mobile. In our simulation, we study the throughput efficiency of JPEG image transmission using EDR packets over mobile Bluetooth network through different error control schemes. Also we discuss the fragmentation process in different cases. In our simulation experiments, we measure the throughput every case. There are three cases in our simulation, which are 1- using standard 2DH3 packets, 2- using standard error control scheme employed for encoding 2DH3 packets (2DM3), and 3- 2DM3 packets are encoded using convolutional code (1, 2, K=3, 7) [Lat 05]. Each one of these cases needs different number of segments [number of segments=image]. In the following, the steps of the JPEG image transmission are described as follows. 1-
Fig. (2). The image (H.jpeg) after converting its size to 600x600
The colored image of simulation (H.jpeg) is JPEG image 400x300 pixels, which is shown in fig. 1. First step in our simulation is converting the image to forms (600x600) square matrix; a new image is shown in Fig. 2. This step is carried out for getting 2-D image matrix.
2-
Second step, converting the image to binary bits matrix.
3-
The third step, converting binary data matrix from 2D matrix to 1-D matrix (long bits stream).
4-
The final step is fragmentation of 1-D matrix to number of segments. Length of each segment equals the packet length. That means the number of segments is not constant but changed with the length of packets changing. The length of packets is shown in section of fragmentation [5].
III. IMAGE FRAGMENTATION & TRANSMISSION Due to the communication channel effects the Bit Error Rate (BER) is much higher and the burst error is expected [5]. Furthermore, the throughput may fluctuate due to time varying characteristics of wireless channel. This section studies the reasons of fragmentation and the number of segments in every case. Our simulation experiments are carried out over the 2.4GHz band in the case of Bluetooth with different cases simulations. Due to the limits of the packets size the fragment of image is important for complete the transmission. The size 3
of the H.jpeg image 360x 10 bytes, then the number of segment calculated from this equation:
No.Segments _1
360x103 8(ImageSize ) 2880(2DH3BluetoothPacket )
(1)
1-Standard 2DH3: In this case of Bluetooth system, length of packet is 3000 bits in the case of uncoded PL of 2DH3 EDR packets. Number of segments is gotten by Equation 1.
No.Segments _2
360x103 8(ImageSize) 2000(2DM 3BluetoothPacket )
(2)
2- The second case is 2DM3: Packets are encoded with using Hamming code (15, 10). This error control scheme is a standard protection technique of classic Bluetooth packets [6]. Equation 2 gives the number of segments and the length of packet is 2000 bits.
Fig. (1). Original image of simulation (H.jpeg)
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No.Segments _3
the number of time slots occupied by the Bluetooth packet, and t is the duration of the Bluetooth time slots.
360x103 8(ImageSize) 1500(2DM 3BluetoothPacket )
(3)
The higher the PSNR and lower NPL mean the more efficient the Bluetooth system performance. In our work, MATLAB was used for carrying out our simulation experiments of different cases. The simulation results have been gotten by transmission of the image over different SNR values.
3- The final case is 2DM3: Packets encoded using convolutional codes (R=1/2 and K (constraint length) =3, 7). As shown in Equation 3, the length of packet is 1500 bits. [6].
V. SIMULATION RESULTS
The length packets in our simulation cases are proposed for simplify the simulation and fragment the image.
In this section, the performance of the proposed transmission of the JPEG image over correlated Rayleigh fading channel is studied through simulation experiments. For the comparison purpose, using standard 2DH3 packets, Encoded 2DH3 packets (2DM3) using standard error control scheme, and encoded 2DM3 using convolutional code (R=1/2) with different constraint lengths are also simulated. In the case of correlated Rayleigh fading channel, we use jack's model in the simulation experiments.
IV. SIMULATION ASSUMPTION In this section, the simulation environment used for carrying out our experiments is described. An important assumption used in the simulation is that a packet is discarded if there is an error Bluetooth packet is discarded if there is an error in the header portion or the data field. This is a realistic assumption to simulate the real Bluetooth system operation [Oza 7].
As mentioned in simulation assumption section, the mobile terminal velocity is 10 mile/hour. The frequency carrier in our simulation is 2.46GHz. In our simulation experiments, 2DH3 packet is used for image transmission. The channel model used for simulations is the jack's model channel model. We assume Bluetooth device which send the photo has a mobile speed of 10 mile/hour. This speed corresponds to a Doppler spread of 36.63 Hz for a carrier frequency Fc = 2.46 GHz. This carrier frequency is one of 79 Bluetooth carriers.
In our simulation experiments, a mobile environment of Bluetooth terminal is taken in our consideration. That means, in our experiments jack model used in the case of correlated Rayleigh fading channel. The mobile Bluetooth device velocity is 10 mile/hour, and the carrier frequency is 2.46 GHz. The Doppler spread is 36.6 Hz. The phase difference between the paths is given from Eq. (3). The Doppler spread is expressed in Eq. (4) [7].
2l 2v c t cos Fd
1 v c cos 2 t
The following experiments are carried out for perform the image transmission over Bluetooth network in correlated fading channel. The simulation is carried out by using jakes’ model.
(4)
(5) 80
70
We will concentrate in our experiments on 2DH3 Bluetooth packets with length (standard length 3000 Bits) for transmitting the JPEG colored image, and the results can be generalized for other Bluetooth packets and other short range wireless systems. In our simulation the length of data field is changed according to the simulation case as shown in previous section. The channel of simulation is correlated Rayleigh fading channel only for simulate the mobile Bluetooth terminal. The peak signal to noise ratio (PSNR) and the Throughput (T) vs. SNR are evaluated. The throughput is given by Equation 6 [Oza 07].
P E A K S NR
60
50
40
30 PSNR OF 2DM3 [CONV[R=1/2, K=3] PSNR OF 2DM3 [HAM1[15,10] PSNR OF 2DH3 [NON INT ]
10
T
PL (1 PER ) (x 1)t
PSNR OF 2DM3 [CONV[R=1/2, K=7]
20
0
10
20
30 Eb/No (dB)
40
50
60
(6) Fig. (3). PSNR vs. SNR for Bluetooth using 2DH3 &2DM3 with standard and proposed cases
PL is the user payload length, PER is Packet Error rate, x is
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Figure 3 gives the results of our experiments, as shown in the figure the highest PSNR is given with using encoded 2DM3 packets using convolutional code [R=1/2, and K (constraint length)=3 and 7]. Fig. 4 gives the throughput (T) vs. SNR, for the case of standard 2DH3 packets and encoded 2DM3 using standard error control scheme (Hamming (15, 10) code.
Figure 5 gives the throughput vs. SNR in case of standard error control and Convolutional code (1, 2, K=3, 7). This experiment reveal, the value of constraint length gives a little effect on throughput but improve the PSNR as shown in Fig. 5. Also, there is a range of SNR, the convolutional code gives better throughput more than Hamming code. From Fig. 5, we can determine the suitable type of packets for getting maximum throughput T.
2
If SNR < 28 d the maximum T is given by using encoded packets ( convolutional code (1, 2, and K=7).
2DH3 [ Uncoded PL=3000]
1.8
2DM3 [Ham(15,10) PL=2000]
Fig. 6 gives a collections results of two previous cases. As shown in this figure, with at low SNR the best choice for getting maximum throughput is convolutional code (1, 2, K=7). With increasing SNR, to reducing the redundant bits the best choice is encoded packets by Hamming code (15, 10). At higher SNR, the uncoded packets become the best.
Throughput (T), M bit/s
1.6 1.4 1.2 1 0.8 0.6 0.4
2
0.2
1.8
2DM3 [Ham(15,10) PL=2000] 2DM3 [Conv[123] PL=1500]
1.6
2DM3 [Conv[127] PL=1500]
2DH3 [Uncoded PL=3000]
0
0
10
20
30
40
50
60
Eb/No, dB Throughput (T),Mbit/S
1.4
Fig. (4). Throughput vs. SNR for Bluetooth using 2DH3&2DM3 with standard [Uncoded and Encoded packets] cases As shown in Fig. 6, the throughput with using uncoded 2DH3 packets is better than encoded 2DM3 [Hamming (15, 10) code that is from SNR > 24 dB, at SNR lower than 24 dB the encoded packets by standard error control gives higher throughput
1.2 1 0.8 0.6 0.4 0.2 0
2
0
10
20
30 Eb/No (dB)
40
50
60
2DM3 [Ham(15,10) PL=2000]
1.8
2DM3 [Conv[123] PL=1500] 2DM3 [Conv[127] PL=1500]
Fig. (6). Throughput vs. SNR for Bluetooth using 2DH3 and 2DM3 with [standard and proposed error control ] cases
Throughput (T), Mbit/s
1.6 1.4 1.2
Our experiments reveal in the range of [SNR=0-28 dB] the encoded EDR 2DM3 packets using convolutional code (1, 2, K=7) is the best choice for getting maximum throughput. That is in case of the redundant bits is ignored. In the range of SNR> 28 dB the standard EDR 2DH3 is better for throughput. In the range of SNR [0-25 dB] the encoded EDR 2DM3 by Hamming code (15,10) is better than standard uncoded packets
1 0.8 0.6 0.4 0.2 0
0
10
20
30
40
50
60
Eb/No, dB
VI. CONCLUSIONS With increasing the applications fields of Bluetooth systems, there is need to improve the throughput over mobile Bluetooth network. The paper studies the throughput of of JPEG image transmission over mobile network using EDR
Fig. (5). Throughput vs. SNR for Bluetooth using 2DM3 with [standard and proposed error control] cases
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[2]
packets. In this paper, we use different error control schemes. From our experiments, in mobile environment, standard error control scheme of previous Bluetooth versions is ineffective where it give little improving of throughput compared with standard 2DH3 case. At low SNR, convolutional code with long constraint length improves the throughput at low SNR till SNR=28 dB. At SNR>28 dB, the uncoded EDR packets gives higher throughput.
[3] [4]
[5]
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