JOURNAL OF TELECOMMUNICATIONS, VOLUME 31, ISSUE 1, JULY 2015

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Patient Monitoring Using Bluetooth and Wireless LAN: A Review

Obianuju Assumpta Ezugwu and Aneke Stephen

AbstractThere are several publications on health related issues, which are the primary concern of everybody. This paper is targeted at investigating and critically analyzing such publications which borders on Monitoring and Tracking of Hospital patients using Bluetooth and Wireless LAN. We looked at the technologies suggested in the research paper and found out the limitations and the areas that need to be improved upon. Index Terms Bluetooth, Wireless LAN, Data transfer, Access point, Sensor, Availability and Reliability.

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1 INTRODUCTION HIS research paper under investigation is an IEEE journal paper. They Opportunistic Medical Monitor-

ing Using Bluetooth P2P Networks. Journal papers and conference papers sometimes are just good for head knowledge and not that they are good to be solutions to problems they claim to be. Some of the information pro-vided are insufficient to be a solution and one of the es-sence of research work is for another person to repeat the process and come up with the same result the way most of the publications end and jump to conclusion, leaving the reader in suspense and gasping for information. D. Cho eta al [1] reflects on how the current tech-nology can be harnessed to be beneficial to the health sec-tor. In talking about patient monitoring, they were firm in suggesting the use of Bluetooth technology as a means of data transmission rather than WiFi, some other technolo-gies such as P2P ad hoc network was also involved to ac-complish this. They identified with two main reasons for embarking on the research work. One of them was to look into the appropriateness and the efficacy of using Blue-tooth in an ad hoc network to gather information on pa-tients and the second objective was to come up with a design on how Bluetooth can be used to generate alarm signal for a patient that needs urgent and emergency at-tention. Cheng and Zhuang [2] in their research work also advocated for the use of Bluetooth technology in enhanc-ing patient monitoring which they demonstrated in a building in Canada. They were more concerned in using Bluetooth to trap the physical location of the patient ra-ther than in sickness monitoring and diagnosis in order to improve on the health of the patient. Alzheimer is a dis-ease that has to do with mental reasoning, their research work did not cover or tell us how the causative symptoms can be monitored technologically though pattern of pa-tients locomotion is a sign of either improvement or dete-rioration. They also looked into some advantages Blue-tooth has over others which include cost, power saving, availability of materials and most convenient for in-house operation due to its short range nature and connectivity. Since Bluetooth cannot operate alone, they talked about others like sensors, access points, and database which will have their respective roles to play in the monitoring.

2 REVIEW OF RELATED LITERATURE 2.1 Wireless LAN The choice of WLAN media was to provide mobility sup-port to the patient, [4] apart from this the comfort and environmental serenity patients enjoy because of the use of WLAN approach to patients monitoring is an edge over the wired approach. [3] Lightweight (centralized architecture) and autonomous (distributed architecture) WLAN architectures are the two approaches in WLAN [5] but in making choice of architecture, scalability and future proof should be considered. WLAN suffers security threats [6] as one of the major problems facing the confi-dentiality of information prevalent in hospital environ-ment. Another issue of utmost interest in this is the centralised management of the WLAN [6] due to increase in patronage and usage coupled with the mobility of users.WLAN

Fig.1: WLAN Physical Network Layout. Source: http://hqwww.panduit.com/panduit/groups/MPM- WC/documents/Articles/107242.pdf

makes use of radio frequency (RF) due to the the presence of access points (AP), it has been suggested that the utilization of this RF be optimised [7] in order to accommodate many other access points that might be present. The reason for many access pointis is that, in a typical WLAN, it is not certain that only one device will be trasmitting at the same time but many other divces will as well be transmitting, therefore these access points are strategically positioned to receive signals from devices they are meant to communicate with. As we said before, WLAN need RF to operate but there are other substitutes

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for RF, they include microwave and infrared transmission[8]. The essence of these is to provide communication between the node (device attached to the patient in order monitor the patient) and the doctors computer (device) via the hospitals database. The actual data trasmission is done using either Frequency Hopping Spread Sprectrum (FHSS) or Direct Sequence Spread Spectrum (DSSS) or the Infrared (IF) [8,9], the APs role is transmitter and receiver.

Fig 2: Physical Operations of IEEE 802.11a/b/g Source: http://rt5vx6na7p.search.serialssolutions.com

IEEE802.11a/b/g standards support WLAN communi-

cation and this communication requires interfaces at both transmitter and receiver ends for linkage with the radio front end [8]. The data generated at the node end have digital properties and cannot be transmitted in that form, it has to be brought to the transmittable format. Before the data is transmitted, it has to be first of all be converted into a baseband waveform, then into an analog format before transmission is done. The same thing happens at the receivers end where the received analog waveform is converted into baseband format and then into bits (0s and 1s) format for the receiving node to use and or store [8].

2.2 Bluetooth Overview

Fig. 3: Bluetooth Wireless PC Card Source: http://electronics.howstuffworks.com/bluetooth1.htm

It is a type of wireless technology that provides support

for local area network of devices.. It operates in such a way that it does not require intermittent user interven-tions for transmissions and it expels minimal energy dur-ing operation [10]. Bluetooth works within a small area network, on the physical level it is essentially a radio fre-

quency standard (uses SSFH technique) for transmission of data from one node to the other, on the protocol level it provides agreement among the products on when bits should be sent, how many should be sent at a time and the number of parties that should participate in order to be sure of message integrity [10,11].

Fig. 4: Architecture of Bluetooth Protocol Source: http://ieeexplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=6202154 The above diagram demonstrates a typical architecture

of Bluetooth technology which basically operates on the principles of Radio specifies the air interface, including the frequency, Baseband which provides connection within the piconet, addressing, packet format, timing and energy (power) control, Link Manager Protocol sets up the link between Bluetooth devices and the management of the link, Logical Link Control and Ad-aptation Protocol causes the upper layer protocol to operate on the baseband layer [9]. Bluetooth technology is preferred to Infrared (IR) tech-

nology because of the shortfalls prevalent in IR. These are mainly the mode of connection which is on the basis of line of sight [9] which is not good in a hospital environ-ment because if an object blocks the line of sight, connec-tion will not be established thereby inhibiting data trans-mission. Another tradeoff is that IR provides support just for one device at a time [9] which is not cost effective and the purpose for establishing the WLAN would be defeat-ed since it is possible for more than one patient to be mon-itored at the same time. Unlike Infrared, Bluetooth is cost effective, easily available in the market from day to day; it operates beyond obstructions within a distance of 10m radius making it possible for patients tracking irrespec-tive of the patients location within the building and again Bluetooth does not consume much energy during opera-

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tion rather it consumes as low as 1mW of power and can be sustained by a 3V battery [10,11].

2.3 Disadvantages of Bluetooth Technology Bluetooth Technology has been used extensively in wire-less network application because of the cost implication and it does not require much expertise to implement. Apart from the encouragement it brought, there some issues with the Bluetooth. One of the issues found in Blue-tooth Technology was identified as [12] Bluetooth pollu-tion. It has been demonstrated that Bluetooth pollution occur as a result of proliferation of Bluetooth devices. Many of these devices despite being within the Bluetooth frequency range, but these are known to be non-cooperating Bluetooth devices. It affects the basic Blue-tooth operations such as inquiry, paging and connection setup.

Bluetooth devices that are involved in networks do not need to disclose their private inputs to other networking devices for computation. This phenomenon is known as [13] Secure Multiparty Computation (SMC). The reason for this is because of the security issue associated with Bluetooth technology. In ad hoc networks, there is no predefined network boundaries, the nodes are free to join and leave the network at any time. This has given room [13] to some of the nodes to compromise the security of the network, an attacker can equally find it easy to join the network unnoticed. In this network, there is no central control facility with which activities on the network can be monitored. Other issues include limited energy re-source for communicating nodes and deterministic net-work scalability [13].

In Bluetooth technology, [14] signals and noise are in-herent. One node transmits at a time and another node receives at a time. Therefore, in order to have a smooth network communication, the receiving node should have a way of separating the unwanted signals from the de-sired ones. This is determined by the ratio of the signal strength of the desired signal to the noise strength at the receiving antenna, the ratio is known as Signal to Noise Ratio (SNR).

3 METHODOLOGY USED IN THE PAPER 3.1 Patient Monitoring and Record Management In this section, the researchers identified two scenarios (Military hospital and old peoples home) and adopted the techniques to support them. They also mimicked NurseNet and BlueAlert modes of data communication.

NurseNet has to do with sending patients data to the central database for storage. NurseNet architecture is shown in the diagram below.

Fig. 5: NurseNet Architecture Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 The NurseNet architecture is composed of three (3) com-ponents which are: Patients, Nurse and Access-Ponts/Central Database/Doctor. Information on the pa-tients were gathered through the aid of sensors that were attached to their bodies. The nurses in attendant were given a mobile (hand held) devices that were connected to patients devices and the central database. The patients device transfers data to the nurse device then from there through a Bluetooth P2P to the central database. The de-livery of the patients data to the database can either be done directly by the nurse who received the data or other nurses can as well assist in doing that. To illustrate how this architecture works, two scenarios were considered. Considering a field hospital that contains 20 40 patients in a row, 5 10 meters apart, and nurses who take turns in attending to them. As the nurses are attending to these patients, their devices are downloading information on the patients. These information are later transferred to the database, it is also shared among the nurse through the P2P manner of which nurse aids take part in doing. An-other case is that of the Nurses taking care of elderly peo-ple, the monitoring device also help the nurses in gather-ing data on these elderly people through their respective devices. The nurses also upload the data to the central database, or share it among themselves. BlueAlert technique is an emergency alarm pro-tocol but it was built on the strength of Bluetooth 2.1.This protocol works on the principle that the signals being sent by the sensors should not exceed certain threshold. But if this threshold is exceeded, the propagation mode changes from BlueTorent to BlueAlert, this will cause steady send-ing of alert messages to other peers that help in the dis-semination of this message

3.2 Experiment This experiment was carried out in a parking garage of size 75m x 75m in order to mimic the hospital and battle field environment, it was carried out in the night to en-sure accurate result.

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Fig. 6: Experiment Scenario (Parking Garage) Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 The components involved in this experiment were Pa-tient, BT-AP (Bluetooth Access point), and three nurses. The patient puts on two different sensors (ECG and purse oximeter, both fabricated by Alive Technology). Each sen-sor transmits 1143 Byte-sensor packet every 240ms on the Bluetooth channel to the patients gateway(a laptop was used in this case). The gateway generates about 70 Kbytes of medical data per minute. The patients node begins to inquire in order to discover nurse upon which the gate-way starts to send list of its data blocks to the nurse. BT-AP- It was only this component that has the ability of providing internet service which enables it to transmit patients data to the Doctor via the internet. The BT-AP periodically performs inquiry to discover the nurse gateway for update on the patients records. Nurse- Three nurses were interconnected using P2P network. Their role was to collect medical infor-mation from the patient and then upload them. The nurs-es walked randomly in the experiment area with their respective laptop at the speed from 0.5 to 1m/s. Bluetooth 2.0 was used for the nurses, patient and the AP. The piece size was set to 500-Bytes making a total of 140 pieces/file, the test was ran for 20 minutes for a total of 5 tests.

3.3 Result

Fig. 7: Number of Packets received by different entities Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 The diagram above shows the contribution of each node to the delivery of the patients medical data to the BT-AP. Nurse nodes exchanged their packets with neighbours to decrease packet delivery latency.

Fig. 8: Number of hops travelled by patients file. Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 From this diagram, there is a display of the fraction of hops the patient file traveled before getting to the destina-tion and the effects of the number of hops on the delivery time of the file. The researchers has shown that more hops reduce the delivery time. Identified problems- The researchers identified the limi-tation of their equipment. Again the inability of the sys-tem to disconnect the connection with the AP as soon as the mobile node moves out of the range. Another problem identified was other nodes trying to connect to a failed node.

Table 1: Packet Delivery Time Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 The table above shows the statistics on the delivery of

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patient data in the experiment. It has an average delivery time of 334.89secs for 100Kbytes of data. On normal cir-cumstance, an average of 300secs is fine but not in case of emergency.

3.4 Simulation Aim: To investigate through simulation NurseNet and BlueAlert. The reason for this simulation is because at the time of this experiment, Bluetooth 2.1 was not yet out and the researchers wanted to show that it can be used to gen-erate emergency alerts for the patients. NurseNet (Scenario 1)

Table 2: Simulation for scenario1

In this scenario, every patient (50 in number) had body sensors and Bluetooth-enabled gateway. The sensors kept generating and transmitting medical data on the pa-tient. Five (5) nurses were involved moving around the area, each having a list of patients to visit. While walking at the speed of 1m/s for 20 secs, a patient is visited and the nurse spends 5mins with the patient. As the nuse is walking to visit a patient, her device gathers information on nearby patients. A record of 100Kbytes were down-loaded within 10secs, 10meters contact window. Once a patient record is read by the nurse, a new record is creat-ed by the patients body LAN. As soon as the nurse gets to the office, she will upload those medical records and resumes patient visitation.

3.5 BlueAlert (Scenario2) This is to demonstrate how emergency alarm can be propagated. Patients are assumed to move in a 100 by 100m2 area. One of the patients needs emergency atten-tion, the Bluetooth gateway on the patient;s body LAN detects the emergency and propagates an emergency alarm message to all the neighbours. The number of hops and the delay before the emergency larm gets to the nurse is measured.

Fig. 9: Collection Delay Fig.10: Uploading Delay Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 The diagrams above show collection and uploading de-lays in the simulation. P2N represents patient to nurse communication. This took place when the nurse was col-lecting patients data. From the result, there was no pa-tients data exchange among the nurses. The delay was 3,000secs. N2N represents nurse to nurse communication. But a situation of P2N +N2N there should be subsequent influence but in this case there is none because the N2N

has nothing to do with patient data collection. Coming to the uploading result, we can notice that in P2N, the delay was 1,000secs and N2N 700secs which suggests N2N communication which reduced the latency.

Fig. 11: No. of Nodes vs Delay Fig. 12: No of Nodes vs No. of Hops Source:http://ieeeplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895 Above are diagrams showing that as the number of pa-tients increases, the number of hops also increases and further reduction in propagation latency by factor of 10 (for 100 nodes).

4 DISCUSSION In the first scenarios that illustrate how NurseNet works have so many flaws when viewing from security perspec-tive. From the illustration, It was noticed that an attacker can easily play masquerade, man in the middle, modifica-tion and non repudiation. Since the nurse opportunistical-ly start to download information on the patient, it then means that anybody with that type of device can as well opportunistically download information on the patient without restrictions. Again the person who claims to be nurse, how truth is it, anybody can pretend to be nurse and do whatever he/she wants to do and get away with it. The idea of either uploading the patients data to the database directly or indirectly should not occur. When such duties are delegated, nobody is responsible for mis-takes or divulging confidential information. Another problem here is high tendency of information duplication which can cause confusion later on. Again the idea of P2P is wrong in such a situation. The principle of P2P is such that no server controls the communication among peers, an attacker can easily sneak in without notice thereby having access to the patients medical information The ideal thing should be the introduction of some security measures to help checkmate the activities of attackers. In such a locality, in order the ensure the confi-dentiality of the patients information, the transmitted data should be encrypted to make it unintelligible if an attacker eavesdrops on it, it is also wise to introduce au-thorization mechanism to ensure that the right personnel assess the patient information.. Authentication and au-thorization will take care of masquerading and man in the middle, modification, and non repudiation attacks. The issue of delegating either another nurse of nurse aid to upload information for another nurse should not come, every nurse should be responsible for his/her duties. Eve-ry nurse should upload the information he/she collected on the patient and the device should be able to append timestamp to the information and the identity of the nurse on duty for accountability sake. The P2P approach should be replaced with client/server approach and instead of nurses uploading the captured medical records, the pa-tients devices should communicate directly with the da-tabase, then to the medical personnel. In case of emergen-

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cy, the server can generate an alert message and forward it to the medical personnel in charge. Though the experiment was carried out in the night but Bluetooth operates on the frequency of free li-cense band of ISM and many other devices compete for this frequency, there is no guarantee that there were no other devices competing at this time of the night since Bluetooth is always on. Again for this idea to be adopted, in real life is it ideal that patients should be monitored only at night to guard against interference of other com-peting devices. If collision avoidance technique is intro-duced in the base of the AP, it will reduce interference of other devices. Multiple transceivers should be installed instead of having one transceiver which is just a single point failure. The introduction of multiple transceivers will not allow transmission to fail if a single transceiver fails.

5 OBSERVATION The idea of using Bluetooth to monitor patients remotely is a good one but the most of the problems encountered which limited the experiment were mainly Bluetooth based. Employing the services of Bluetooth alone is not enough to give the performability needed in a health en-vironment. However, there are areas that need to be ad-dressed; they are the incorporation of other technology such as 3G, WLAN and real time operating system in pa-tient monitoring. Another issue that should be looked into is the effect of patients body temperature on the sensor node and the effect of the signals emitting from the Blue-tooth on the patients health.

6 CONCLUSION The researchers were able to prove the contribution of Bluetooth to the health sector. Making use of the short range coverage nature of Bluetooth and ability not to be obstructed by the presence of barriers such as walls facili-tates reaching out to patients not minding their location within a building. However Patient monitoring using Bluetooth with P2P network technology is not an ideal setup for hospital service rather there should be a way to integrate a more recent technology like 3G or 4G so that patients data are not restricted to data transmission only but voice and multimedia should be transmitted equally.

REFERENCES [1] D. Cho, S. Lee, A. Chang, T. Massey, C. Chang, M. Tsai, M. Sar-

rafzadeh, and M. Gerla (2008, August) Opportunistic Medical Monitoring Using Bluetooth P2P Networks, IEEE Journal, 978-1-4244-2100-8/08/$25.00. Available: http://ieeexplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=4594895

[2] H.T. Cheng, W.Zhuang, Bluetoot-Enabled In-Home Patient Moni-toring System: Early Detection of Alzhoimers Disease, IEEE Wire-less Communication, 1536-1284/10/$25.00, 2010. Available: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5416353

[3] T. V. Ngoc, Medical Application Of Wireless Networks,Available: http://www.cse.wustl.edu/~jain/cse574-08/ftp/medical.pdf

[4] H. Chen, D. Ye, J. Lee, Development of a portable EEG Monitoring System based on WLAN, Proceedings of the IEEE International Conference on Networking, sensing and Control, 1-4244-1076-

2/07/$25.00, 2007. Available: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4239035

[5] http://hqwww.panduit.com/panduit/groups/MPM-WC/documents/Article/107242.pdf

[6] http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4470091

[7] P. Yue , X.Yi , Z.Liu, A Novel Wireless Network Architecture And Its Radio Frequency Assignment Mechanism For WLAN Based On Distributed Antenna System Using Radio Over Free Space Optics , Proceeding of IEEE International Conferenc e on Information Sci-ence & Technology ,978-1-4244-9442=2/11/$26.00, 2011 Available: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5765297&tag=1

[8] http://www.netlab.tkk.fi/opetus/s38118/s00/tyot/25/page2.shtml

[9] K. Tan and et al: Sora: High Performance Software Radio Using General-Pupose Multi-Core Processors, Communications of ACM, Vol 54, No 1, 2011, DO1:10:1145/1866739.1866760.Available: http://rt5vx6na7p.search.serialssolutions.com

[10] How Stuff Works, 1998-2013: Available: http://electronics.howstuffworks.com/bluetooth1.htm

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[12] S. Asthana and D. N. Kalofonos (2005, August) The Problem of Bluetooth Pollution and Accelerating Connectivity in Bluetooth Ad-Hoc Networks, IEEE Proceedings of the 3rd Intl Conf. on Pervasive Computing and Communications (PerCom 2005) 0-7695-2299-8/05 $20.00 2005. Available: http://ieeexplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=1392756&tag=1

[13] R. Sheikh, M.S. Chandel and D.K. Mishra, Security Issues in MANET: A Review, IEEE Journal, 978-1-4244-7202-4/10/$26.00 2010, Available: http://ieeexplore.ieee.org.ezproxy.mdx.ac.uk/stamp/stamp.jsp?tp=&arnumber=5587317

[14] J. Lansford, A. Stephens, and R. Nevo, (2001, October) Wi-Fi (802.7 7 b) and Bluetooth: Enabling Coexistence, IEEE Journal, 0890-8044/01/$10.00, Available: http://ieeexplore.ieee.org.ezproxy.mdx.ac.uk/ielx5/65/20610/00953230.pdf?tp=&arnumber=953230&isnumber=20610

Obianuju Assumpta Ezugwu is a lecturer at the Department of Computer Science, University of Nigeria Nsukka. She has B.Sc in 1998 and M.Sc in 2008, Computer Science from University of Nigeria. Her research interests are Software Development and Research Support System. She is a member of Nigeria Computer Society, Com-

puter Professionals, Nigerian Women in Information Technology, and Organisation for Women in Science for the Developing World.

Aneke Stephen apart from currently lecturing at the Department of Computer Science, has worked with SchoolNet Global (2006) and Microsystems Services Ltd (2002-2004) as network specialist and Internet administrator respectively. He has HND (Computer Science) from Institute of Man-agement and Technology in 1997, PGD (Computer Science) from Nnamdi Azikiwe University in 2006

and M.Sc (Computer Networks) in 2013 from Middlesex University, London. Research interest includes Network Modelling & Simulation, Real-Time streaming data analysis and Network QoS. A member of CISCO Academy.