Blood pressure is one of the most important indicators of human health condition. A patient with hypertension in long term tends to have various kinds of vessel pathological changes such as coronary heart disease, apoplexy, and nephropathy. Consequently, the blood pressure measurement is important in daily health care for hypertension patients. Traditionally, the design and implementation of blood pressure monitor mostly focuses on the accuracy of pressure measurement and does not deal with the requirement of hypertension health care services with two-way communication via instant messages between the patient and the medical center. In this paper, a mobile-care system integrated with Bluetooth blood pressure and pulse monitor, and cellular phone is designed and implemented to transmit the physiological parameters of the patient in real time via wireless networks. The health care provider can monitor the blood pressure, body temperature, and heart rate of the patient and provide services by intelligent health care systems. The intelligent system constantly manages the health care data and periodically reports the status of the patient to the patient's family members. By the above care mechanism, the patients with hypertension can easily obtain long-term and constant monitoring of the physiological parameters and thus better health care services. A questionnaire survey has been conducted among medical personnel in Taipei municipal Wang-Fang hospital to collect their opinions of using our proposed and implemented blood pressure monitor with Bluetooth transmission function. An average of 95% of the medical personnel agree that long-term monitoring of the patients' physiological information such as blood pressure can be helpful to reduce medical cost, to provide useful reference data, and to provide long-distance health care. This thus shows strong support of the usefulness of our proposed device. Our proposed and implemented device has also been submitted to US FDA for medical device approval.

In this paper, we present Blueweb, a new Bluetooth-based multihop network with an efficient scatternet formation algorithm and a hybrid routing protocol. The Blueweb is designed from the original idea of Bluetree. Blueweb's scatternet formation uses two mechanisms. One is the role exchange mechanism in which only slave nodes serve as the role of relay through the whole scatternet. The other one is the return connection mechanism in which we convert the scatternet from a tree-shaped to a web-shaped topology. Meanwhile, a modified source routing protocol is designed for Blueweb in which we combine the proactive method with the reactive method to discover the optimal path for packet transmission. Furthermore, using computer simulations we compared the system performance of Blueweb and Bluetree with both a static model and a uniform traffic model. With the static model we evaluate the scatternet performance and with the uniform traffic model we evaluate the transmission performance. Our simulation results show that Blueweb achieves superior system performance than Bluetree on both scatternet performance and transmission performance.

Bluetooth is reputed as a wireless networking technology capable of forming ad-hoc networks between digital devices. In particular, the Bluetooth scatternet will be an essential part of the fully distributed ad-hoc networks. However, scatternet is not fully described in the Bluetooth specification. This has been the topic of discussion among researches in relation to the formation algorithm, scheduling scheme, etc. Most of the proposed algorithms reported in past researches on scatternet formation are too large and complex to be implemented in a real commercial Bluetooth hardware. Therefore, the verifications of the proposed algorithms reported in past researches were done through only simulations. In addition, the formation process takes too long and these past researches had been conducted only in static environment where no node enters or leaves the scatternet. In this paper, therefore, we propose a new scatternet formation algorithm called Node Ring Scatternet (NRS), emphasizing on two aspects, i.e. implementation and dynamic property of the algorithm. The algorithm is very simple and compact and is verified to be easily implementable in a real commercial Bluetooth device. For the dynamic properties, the NRS entails relatively short formation delay and a reformation algorithm in a dynamic environment was designed. Therefore, the network of the NRS can be scalable and flexible. In addition, a new protocol called SFMP (Scatternet Formation & Management Protocol) was designed and is presented herein. Using this protocol, the NRS algorithm was implemented in a real Bluetooth device, and the performance was verified through hardware experiments. Based on the experimental results, it was found that the NRS composed of up to 20 nodes is formed and the proposed algorithm has shown improvement in terms of formation delay, formation probability and reformation.

We have studied on the interference test method from IEEE802.11b to IEEE802.11g as an interference source with wide band spectrum by using the opened PW cell, and it is clear that the throughput of IEEE802.11g for only IEEE802.11b Ch.4 signal wave as the interference wave, whose frequency spectrum is almost not overlapping with IEEE802.11g, is almost not interfered by IEEE802.11b, but the throughputs for all other channels from Ch.5 to Ch.8 as the interference wave are interfered and decrease to below 2 Mbps. By comparing with conventional radiated RF electromagnetic field immunity test specified by IEC 61000-4-3, it is clear that the conventional immunity test cannot simulate the interference phenomena from IEEE802.11b to IEEE802.11g. Next, we tried to perform the interference test of the Bluetooth against the wireless LAN IEEE 802.11b as a disturbance source. As a result, it is revealed that the throughput of Bluetooth decreases according to increasing the interference wave level, and communication between EUT (slave) and the master of Bluetooth is interrupted for the interference wave corresponding to Ch.7 (244210 MHz). However, in the conventional immunity test specified by IEC 61000-4-3, the throughput of the Bluetooth does not affect for the all disturbance waves corresponding to the center frequency of bandwidth on the cannel of IEEE802.11b. Therefore, it is needed for the wireless LAN and the Bluetooth to develop new radiated immunity test method, which has the disturbance wave with wide bandwidth.

In this paper, we describe a development of a Bluetooth Access Point for the WAN connection of home network devices. Especially, users can access the PSTN at home instead of expensive CDMA network through the AP, using the 'one-phone,' which is the Bluetooth enabled cellular phone. The one-phone service becomes a convergence of wired and wireless communication through the AP.

A frequency drift of open-loop PLL is an issue for the direct-modulation applications such as Bluetooth transceiver. The drift mainly comes from a temperature variation of VCO during the transmission operation. In this paper, we propose the optimum location of the VCO, considering the temperature gradient through the whole-chip thermal analysis. Moreover, a novel temperature-compensated VCO, employing a new biasing scheme, is proposed. The combination of these two techniques enables the power reduction of the transmitter by 33% without sacrificing the performance.

The use of a two-point modulator with variable PLL loop bandwidth as a GFSK signal generator is proposed. Delta-sigma modulation is adopted for the modulator. Through the combination of a variable PLL feedback loop and delta-sigma modulation, both a fast settling time and very clear eye opening are achieved for the modulator. We fabricate it in 0.35-µm BiCMOS process technology. The two-point modulator has a center-frequency drift of only 14.9 kHz, much lower than the 178-kHz result for a single time slot in the case of direct VCO modulation. This is due to the PLL feedback loop. Evaluation also confirmed that the circuit satisfies the various characteristics required of a Bluetooth transmitter. The two-point modulator is also applicable to other transceivers which use FSK or PSK modulation, i.e. forms of modulation where a constant signal level is transmitted, and thus contributes to the simplification of a range of wireless transmitters.

Topology of a network greatly affects the network performance. Depending on the purpose of a network, a specific topology may perform much better than any other topologies. Since the ad hoc networks are formed for a specific purpose, determining, and constructing the network topology based on the application requirements will enhance system performance. This paper proposes Bluetooth scatternet forming protocol in which the network topology is determined by three parameters. The parameters affecting the topology are the number of maximum slaves in a piconet, the number of maximum piconets that a gateway Bluetooth device can service, and the number of loops needed in the formed scatternet. These parameters can be read from a script file prior to the network formation. This process of reading the important parameters from the file would give users freedom in determining the network topology. The proposed protocol also includes a role negotiation process to accommodate different capabilities of the participating devices. The negotiation process of the protocol allows the resource-limited nodes to participate in the network. Different types of scatternet topologies like star, mesh, ring and line can be formed by specifying the parameters. This paper also discusses theoretical information necessary for calculating network topologies in detail. The protocol is verified with help of simulations, and implementations using commercially available Bluetooth devices. The detailed results are also presented in this paper.

This paper considers an efficient scheduling policy for Bluetooth Medium Access Control (MAC) and its parameter optimization method. The proposed algorithm improves performance as well as supports Quality of Service (QoS) simultaneously. Since Bluetooth is basically operated with a Round Robin (RR) scheduling policy, many slots may be wasted by POLL or NULL packets when there is no data waiting for transmission in the queues of the polled pair. To overcome this link wastage problem, several algorithms have been proposed. However, they have some limitations such as a heavy signaling overhead or no consideration of QoS. Therefore, we have proposed an efficient Bluetooth MAC scheduling algorithm, Differentiated K-Fairness Policy (Diff-KFP), which guarantees improved throughput and delay performance, and it can also lead to differentiated services. That is, if the parameter of the proposed algorithm is optimized, we can satisfy the QoS requirement of each master-slave pair and thereby keep communications in progress from interruption, which is a source of throughput degradation. Simulation results show that our algorithm has remarkably improved the performance and gratifies the QoS requirements of various applications.

Bluetooth is a system for providing short-range, small size, low-power and low-cost connectivity operating in the ISM (Industrial Scientific Medicine) band at 2.4 GHz. Bluetooth has been seen as a promising candidate for ad-hoc wireless networking and wireless personal area network (WPAN). In this paper, we first discuss previously proposed polling algorithms in Bluetooth piconet. We then propose an efficient fair scheduling algorithm which improves the throughput efficiency of the system by adaptively assigning the polling interval according to the number of inactive slaves. We also show the simulation results of the proposed algorithm compared with previously proposed algorithms.

In this paper, we propose an algorithm, named efficient utilization polling (EUP), to support asynchronous data traffic at MAC layer by using the characteristics of Bluetooth technology. The algorithm uses a single bit in the payload header to carry the knowledge of queues in slaves for dynamically adapting the polling intervals for achieving the goals of high channel utilization and power conserving. In addition, we propose a differentiation mechanism, named shift-polling window (SPW). Based on EUP, the SPW differentiates the throughput from various classes, and still keeps the link utilization high and almost the same as that of the best-effort services. Extensive simulations are experimented on the behavior of the EUP and SPW by tuning the related parameters, such as polling interval, buffer size, queue threshold level, etc., in order to verify the expectation of these methods.

This paper examines the effect of segmentation mismatch on audio-video transmission by Bluetooth. We focus on the segmentation mismatch caused by the difference between the RFCOMM Maximum Frame Size and the baseband packet payload size. By experiment, we assessed the maximum throughput and media synchronization quality for various types of ACL packets. In the experiment, a media server transferred stored video and audio streams to a single terminal with point-to-point communication; we supposed no fading environment and added white noise by which interference from DSSS systems is modeled. The experiment showed that the effect of segmentation mismatch is large especially when the total bit rate of the two streams is near the channel transmission rate. We also observed that the media synchronization control is effective in compensating for the disturbance by the segmentation mismatch in noisy environments.

We have proposed a new low-IF transceiver architecture to simultaneously achieve both a small chip area and good minimum input sensitivity. The distinctive point of the receiver architecture is that we replace the complicated high-order analog filter for channel selection with the combination of a simple low-order analog filter and a sharp digital band-pass filter. We also proposed a high-speed convergence AGC (automatic gain controller) and a demodulation block to realize the proposed digital architecture. For the transceiver, we further reduce the chip area by applying a new form of direct modulation for the VCO. Since conventional VCO direct modulation tends to suffer from variation of the modulation index with frequency, we have developed a new compensation technique that minimizes this variation, and designed the low-phase noise VCO with a new biasing method to achieve large PSRR (power-supply rejection ratio) for oscillation frequency. The test chip was fabricated in 0.35-µm BiCMOS. The chip size was 3 3 mm2; this very small area was realized by the advantages of the proposed transceiver architecture. The transceiver also achieved good minimum input sensitivity of -85 dBm and showed interference performance that satisfied the requirements of the Bluetooth standard.

A 1-V 2.4-GHz-band fully monolithic PLL synthesizer was fabricated in 0.2-µm CMOS/SOI process technology. It includes a voltage-controlled oscillator (VCO) and a 3-GHz fully differential dual-modulus prescaler on a chip. A low-off-leakage-current charge pump is used for open-loop FSK modulation. When the PLL is in the open loop mode, the frequency drift of the output is lower than 2.5 Hz/µsec. The output phase noise is -104 dBc/Hz at 1-MHz offset frequency. The power consumption of the PLL-IC core is 17 mW at 1-V supply voltage. This PLL synthesizer is suitable for a 1-V Bluetooth RF transceiver LSI.

Management of diet and exercise is especially significant in preventing "lifestyle-related diseases" for patients and subclinical cases. This paper introduces a questionnaire survey on diabetic regimens that targets 38 professional users such as physicians and nurses at a diabetic clinic. Based on the results of the questionnaire survey, a design concept for a wearable healthcare support system has been developed to provide patients with timely instruction in accordance with their current context. On the basis of this design concept, we developed a prototype of a wearable healthcare support system called "LifeMinder". "LifeMinder" is composed of a wristwatch-shaped wearable sensor module and a personal digital assistant (PDA). The sensor module measures 3-axis acceleration, pulse rate, galvanic skin reflex (GSR), and skin temperature. The PDA receives this data via BluetoothTM and recognizes the patient's general behavior such as "walking" or "eating". The recognition of these behaviors reduces the patient's mental and physical burden in daily healthcare and assists in support of medical treatment.

This paper describes a full-CMOS single-chip Bluetooth LSI fabricated using a 0.18 µm CMOS, triple-well, quad-metal technology. The chip integrates radio and baseband, which is compliant with Bluetooth Core Specification version 1.1. A direct modulation transmitter and a low-IF receiver architecture are employed for the low-power and low-cost implementation. To reduce the power consumption of the digital blocks, it uses a clock gating technique during the active modes and a power manager during the low power modes. The maximum power consumption is 75 mW for the transmission, 120 mW for the reception and 30 µW for the low power mode operation. These values are low enough for mobile applications. Sensitivity of -80 dBm has been achieved and the transmitter can deliver up to 4 dBm.

This paper analyzes the voice packet dropping probability and the average message transmission delay of a Bluetooth radio link in which talkspurts and messages are simultaneously transmitted as voice packets and data packets over an SCO (Synchronous Connection-Oriented) link and an ACL (Asynchronous ConnectionLess) link, respectively. The behaviors of an SCO link and an ACL link are modeled using Markov processes. Using these two Markov models and EPA (Equilibrium Point Analysis), the voice packet dropping probability and the average message transmission delay are derived analytically in terms of the permission probability of a voice packet and a data packet, the length of a message, the number of slaves, and the arrival rate of the messages. Some numerical examples are given to show how the permission probabilities, the number of slaves and other parameters influence the transmission delay, when both the SCO link and the ACL link are used at the same time.

In this paper, we describe the implementation and the test results of a Bluetooth baseband module we have developed. For small chip size, we eliminate FIFOs for data buffering between hardware functional units and data buffers for bit streaming among channel coding blocks. Furthermore, we carefully consider hardware and software partitioning. We implement complex control tasks of the Bluetooth baseband layer protocols in software running on an embedded microcontroller. Hardware-efficient functions, such as low-level bitstream link control; host controller interfaces (HCIs), such as universal asynchronous receiver transmitter (UART) and universal serial bus (USB) interfaces; and audio CODEC are performed by dedicated hardware blocks. In addition, the bitstream data path block of the link controller constructing the baseband module has been designed by considering low power. The design of the baseband module is done using fully synthesizable Verilog HDL to enhance the portability between process technologies. A field programmable gate array (FPGA) implementation of the module was tested for functional verification and real time operation of file and bitstream transfer between PCs. The module was also fabricated in a 0.25 µm CMOS technology, the core size of which is only 2.792.80 mm2.

The Bluetooth system provides point-to-point or point-to-multipoint communications with no peer-to-peer communication. For peer-to-peer communication, a slave should be able to communicate with other slaves as well as a master. To do this, the master should indirectly forward the packets. However, the end-to-end delay of forwarding packets may be increased because the packets should be forwarded at network layer. Forwarding packets for peer-to-peer communications may also bring about some needless waste of wireless resource. In this paper, we propose the addressing policy for efficient peer-to-peer communications in Bluetooth. We also address the dynamic master selection policy in which a master is dynamically selected in order to minimize the average channel occupancy. To dynamically change master in a piconet, the master-slave switching should be executed as soon as possible. Therefore, we propose the fast master-slave switching mechanism in order to minimize the switching delay. It is observed from the simulations that our proposed policies perform better than the naive Bluetooth specification.

We expect that most cellular phones and notebook computers will have Bluetooth in the near future. Many convenient applications will flourish. An example is exchanging multi-media electronic name cards using cellular phones. Today, most people carry a cellular phone. If the user interface can be made as simple as handing out a printed business card, the electronic cards exchanged over Bluetooth would make printed ones obsolete. However the current Bluetooth specification is not adquate to support short peer-to-peer transactions requiring symmectric user interface and fast response time. Connection establishment can take more than 10 s and two devices must start in an asymmetric manner. In this paper, we propose a random inquiry procedure tailored for name card exchange. It allows a symmectric user interface, and device discovery completes within 280 ms with probability 0.999. With this performance, it then becomes practical to provide a hot button on cellular phones that users will simply press to exchange electronic name cards.