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An impulse radio UWB transceiver with high-precision TOA measurement unit
Abstract
This paper describes a monolithic integrated transceiver chipset intended for impulse radio (IR) Ultra-wide band (UWB) applications including indoor communication and indoor localization. The chipset operates in the higher UWB band centered at 7.68 GHz and it is optimized for a pulse bandwidth of about 1.5 GHz. The average pulse repetition rate of 60 MHz and an octagonal pulse position modulation (8-PPM) allow for raw data rates up to 180 MBit/sec. The available high bandwidth is used for precise indoor localization employing a dedicated time-of-arrival (TOA) measurement extension. This unit runs with an on-chip system clock of 3.84 GHz, which allows a measurement accuracy of 260 picoseconds. As demonstrated this UWB transceiver chipset is well suited for two-way ranging (TWR) in potentially harsh RF propagation environments. Under perfect line-of-sight conditions a spatial resolution of about 3.9 centimeter could be achieved.
... For indoors, we compare our results with other works who covered the same field. However, these works focused on resolving the most common problems of ToA signals [130,131,132,133], meanwhile, we proposed a solution for the step after these ToA estimations. As we are working on two different visions we can only compare the final result which is the accuracy. ...
... As we are working on two different visions we can only compare the final result which is the accuracy. The best accuracy we could find in the literature was of 3, 9 cm in perfect LOS [130] and less than 30 cm for NLOS indoors [131]. With the results presented in Section 5.4.2, we can conclude that we obtained more accurate results compared to other papers. ...
This thesis studies D2D communication in realistic and challenging scenarios for future wireless systems. In particular, the thesis focuses on how may D2D communication help other technologies to enhance their performance. The first wireless scenario is the one of multicasting, used for example in video streaming or common alert message transmission for police, firefighters or ambulances. The second wireless scenario is the critical one of URLLC expected to be used to avoid cars crashes in the upcoming V2X context, and also when connecting machines together in environments like connected hospitals, airports, factories (industry 4.0), and last but not least in e-health context in order to enhance medical tele-surgery. The last wireless scenario is the one of UE group localization in the context of massive IoT, where devices are interacting with each other and are mostly confined in local groups, needing local services. In the multicast channel scenario, where a transmitter wishes to convey a common message to many receivers, it is known that the multicast rate decrease as the number of UEs increases. This vanishing behavior changes drastically when enabling the receivers to cooperate with each other via D2D. Indeed, the multicast rate increases with high probability when the number of receivers increases. This chapter also analyzes the outage rate of the proposed scheme in the same setting. Extensions regarding firstly resource utilization and secondly considering the use of HARQ are also analyzed. Next chapter addresses one of the major challenges for future networks, named URLLC. Specifically, the chapter studies the problem of HARQ with delayed feedback, where the transmitter is informed after some delay on whether or not his transmission was successful. The goal is to minimize the expected number of retransmissions subject to a reliability constraint within a delay budget. This problem is studied at two levels: (i) a single transmitter faced with a stochastic i.i.d. noisy environment and (ii) a group of transmitters whom shares a collision channel. Then the chapter that follows provides a cooperative UE mapping method that is highly accurate. Four different channel models are studied in this chapter: LOS and NLOS for indoor and outdoor environments. The results show significant improvement compared to already existing methods. Identifying the dense local areas in real time and informing the network allows the Base Station (BS) to increase the capacity through highly directive beams, and therefore, avoids the deployment cost of new infrastructure.
... For indoors, we compare our results with other works who covered the same field. However, these works focused on resolving the most common problems of ToA signals [130,131,132,133], meanwhile, we proposed a solution for the step after these ToA estimations. As we are working on two different visions we can only compare the final result which is the accuracy. ...
... As we are working on two different visions we can only compare the final result which is the accuracy. The best accuracy we could find in the literature was of 3, 9 cm in perfect LOS [130] and less than 30 cm for NLOS indoors [131]. With the results presented in Section 5.4.2, we can conclude that we obtained more accurate results compared to other papers. ...
Dans cette thèse, nous étudions plusieurs scénarios de communication pour les futurs réseaux sans fil. Plus particulièrement, cette thèse porte son attention sur comment la communication directe entre équipements mobiles (D2D) peut améliorer les performances des technologies existantes dans les systèmes sans fil. Le premier scénario étudié durant cette thèse est celui de la communication par multidiffusion d’un message commun entre un émetteur et plusieurs récepteurs. Il peut être illustré par le streaming vidéo, les messages d’alerte à destination de la police ou des pompiers ou des ambulanciers. Le second scénario étudié est celui d’une transmission à contraintes critiques en latence et en fiabilité. Ce dernier est illustré par son implication primordiale dans les futures technologies telles que les voitures connectées, avec pour but d’éviter des accidents, ou bien les machines connectées pour améliorer les services hospitaliers tels que la télé-chirurgie entre autres. Le dernier scénario étudié est celui de la localisation d’un groupe d’équipement dans un réseau densément peuplé tel qu’on peut trouver dans le contexte des objets connectés en masse. En général les objets communiquent entre eux à un niveau local et sont intéressés par des services communs et locaux. Plus concrètement, dans cette thèse, nous montrons les bienfaits de la communication D2D dans les trois scénarios précédents. Dans le cas du premier scénario de multidiffusion, contrairement à la tendance habituelle d’avoir un taux de transmission qui diminue en fonction du nombre d’équipements mobiles (en particulier, car l’équipement émetteur doit adapter sa transmission à l’équipement récepteur en plus mauvaise condition), en ajoutant la communication D2D, on observe que ce même taux de transmission augmente en fonction du nombre d’équipements mobiles présents. Dans le deuxième scénario où la communication est soumise à des contraintes de fiabilité et de latence exigeantes, nous déduisons une politique de retransmission optimale et proposons une autre politique semi-optimale qui est beaucoup moins gourmande en temps et qui a prouvé son optimalité dans plusieurs cas pratiques. Enfin dans le dernier scénario, nous proposons une méthode de localisation d’équipements mobile et l’étudions dans plusieurs environnements (avec et sans visibilité directe dans les cas intra-muros et extérieurs). L’identification de ces zones est ensuite utilisée pour créer de petites cellules virtuelles adaptatives aux situations changeantes et non prédictibles, dans le but de réduire les coûts liés aux infrastructures actuelles.
... For indoors, we compare our results with other works who covered the same field. However, these works focused on resolving the most common problems of ToA signals [13] [14] [15] [16], meanwhile, we proposed a solution for the step after these ToA estimations. As we are working on two different visions we can only compare the final result which is the accuracy. ...
... As we are working on two different visions we can only compare the final result which is the accuracy. The best accuracy we could find in the literature was of 3, 9 cm in perfect LOS [13] and less than 30 cm for NLOS indoors [14]. With the results presented in section IV-B, we can conclude that we obtained more accurate results compared to other papers. ...
... In 2002, the Federal Communications Commission (FCC) liberated an unlicensed frequency band that goes from 3.1 GHz to 10.6 GHz, with emission power level limited to −41.3 dBm/MHz [8]. Since then, an increasing interest for Ultra-Wideband (UWB) LPS has appear [9][10][11][12][13][14]. This is because, theoretically, location with UWB systems in NLOS conditions and with accuracy in the decimetre range is feasible. ...
... In [20] the sampling of a signal with a bandwidth of 1.6 GHz is accomplished by means of a 5 GS/s digital oscilloscope. Other challenges that UWB-based LPS have to face are emitter-receiver synchronization, Inter-Symbol Interference (ISI), Multiple Access [11,13,14]. Nevertheless, considering the high sampling rates required in an asynchronous system with TDMA, a prohibitive memory depth would be required in order to ensure sampling a frame that contains the signals from all the beacons. ...
In Ultra-Wideband (UWB) Local Positioning Systems (LPS), Inter-Symbol Interference (ISI), Multiple-Access Interference (MAI) and near-far effect are significant issues that can limit system performance. This paper presents a DS-UWB (Direct Sequence UWB) LPS based on FPGAs (Field-Programmable Gate Array) and on commercially available Radio-Frequency (RF) modules. In contrast to other DS-UWB LPS, which uses TDMA (Time Division Multiple Access) and base-band pulses with low-repetition frequency rates, the proposal uses QS-CDMA (Quasi-Synchronous Code Division Multiple Access) techniques with Loosely Synchronized (LS) spreading sequences. This allows to deal with ISI, MAI and near-far effect, as well as to use very large spreading sequences to increase the processing gain.
... The location is the intersection of circles with radius equal to the distance between the target and reference nodes and calculated as the one-way propagation time between them [87][88][89]. ...
Quantitative indoor monitoring, in a low-invasive and accurate way, is still an unmet need in clinical practice. Indoor environments are more challenging than outdoor environments, and are where patients experience difficulty in performing activities of daily living (ADLs). In line with the recent trends of telemedicine, there is an ongoing positive impulse in moving medical assistance and management from hospitals to home settings. Different technologies have been proposed for indoor monitoring over the past decades, with different degrees of invasiveness, complexity, and capabilities in full-body monitoring. The major classes of devices proposed are inertial-based sensors (IMU), vision-based devices, and geomagnetic and radiofrequency (RF) based sensors. In recent years, among all available technologies, there has been an increasing interest in using RF-based technology because it can provide a more accurate and reliable method of tracking patients’ movements compared to other methods, such as camera-based systems or wearable sensors. Indeed, RF technology compared to the other two techniques has higher compliance, low energy consumption, does not need to be worn, is less susceptible to noise, is not affected by lighting or other physical obstacles, has a high temporal resolution without a limited angle of view, and fewer privacy issues. The aim of the present narrative review was to describe the potential applications of RF-based indoor monitoring techniques and highlight their differences compared to other monitoring technologies.
... In the next section, we compare our results to GPS approach used in our first group localization method in Section 5.1 whose error localization will be considered and is around 10 m in LOS outdoor environment [51]; as GPS remains the notorious outdoor localization technique. Meanwhile, we propose a solution for the step after ToA estimations, several works focus on resolving the most common problems of ToA signals [52][53][54][55]. Please notice that we can achieve even better results with our The simulation results show that the localization accuracy in LOS environments has an estimation error below 2 cm in 73% of the cases and below 55 cm in 71% of the case in NLOS environments algorithm while combining these two visions, i.e., use efficient ToA as input to our algorithm. ...
Next wireless generation mobile networks will be composed of a large number of antennas at the base station (BS), which is known as massive multiple input multiple output (MIMO). Thanks to this technology, the BS can focus the energy on a user equipment (UE) or group of UEs to improve their throughput and the network capacity. We call these coverage areas virtual small cells (VSCs). Their main advantage is that they allow increasing the network capacity through a virtual densification, therefore, avoiding the deployment cost of new infrastructure. Identifying the dense traffic areas in real time and providing a good quality of service arises as a key challenge to be addressed. Our work focuses on the interaction between the VSCs and the identification of the dense traffic areas, where a feedback scheme is proposed. This feedback scheme is based on the location of these dense traffic areas provided by our proposed clustering methods. To conduct this research, we propose (i) a VSC architecture and system model with a specific codebook in order to avoid feedback overhead, and (ii) two positioning algorithms in order to determine the hotspots localization. The first positioning algorithm is based on K-means method and is centralized at the BS using Global Positioning System (GPS) coordinates, and the second one is based on cooperative communications using ultra-wideband (UWB) signals in order to avoid the network participation. Finally, simulations of these positioning methods intended for the use of the VSCs are presented. These results show significant improvement compared to already existing methods. Furthermore, these positioning methods highly reduce the feedback since, accordingly to our VSC model, the BS only requires angles information based on the localized hotspots.
... In [16], an accuracy of under 10 cm was achieved in an indoor environment using UWB pulse signals. Fischer et al. reported 3.9 cm localisation accuracy by utilising IR-UWB transceivers in [17]. However, all these investigations have only considered localisation of tags placed in free space. ...
This paper presents experimental investigations on high precision localization methods of body-worn miniature antennas using ultra-wideband technology in line-of-sight conditions. Time of Arrival data fusion and peak detection techniques are implemented to estimate the three-dimensional location of the transmitting tags in terms of x, y, z Cartesian coordinates. Several pseudo-dynamic experiments have been performed by moving the tag antenna in various directions and the precision with which these slight movements could be resolved has been presented. Some more complex localization experiments have also been undertaken, which involved the tracking of two transmitter tags simultaneously. Excellent 3D localization accuracy in the range of 1-4 cm has been achieved in various experiment settings. A novel approach for achieving sub-centimetre 3D localization accuracy from UWB technology has been proposed and demonstrated successfully. In this approach, the phase centre information of the antennas in a UWB localization system is utilized in position estimation to drastically improve the accuracy of the localization measurements to millimetre levels. By using this technique, the average localization error has been reduced by 86%, 31% and 72% for the x, y and z axes coordinates, respectively.
... GPS 위치 측정은 광범위한 지역을 대상으로 3∼5m의 오차 범위를 가진다 [5] . GPS의 [6] , UWB (Ultra Wide Band) [7] , 적외선 [8] , 초음파 [9] 등의 다양한 실내 측위 기술이 제안되었다 [1012] . 이들 기술은 실내 공간의 특징, 측위 인프라 구축의 난이도 등에 따라 측위 가능 범위와 측위 정확도에서 여러 차이를 보인 다 [13] . ...
In this paper, we propose a ultrasonic and RF-based indoor localization system. In previous work, various systems were proposed for indoor localization, but they have limitation in applicability due to time-synchronization, complexity, or accuracy. To overcome such problems, an indoor localization system with ultrasonic and RF is proposed. A transmitting system is composed of a pair of ultrasonic and RF transmitters and the receiving system is composed of multiple ultrasonic receivers and one RF receiver. The theoretical performance limitation is also analyzed. To verify localization performance, we have implemented a receiving systems and a transmitting system using Arduino modules. Experiments were performed in 2m{\times}2m{\times}2m space and the localization errors had a mean of 6.1cm and a standard deviation of 1.6cm.
... Figure 12 depicts the common setting for UWB-based localization system. In general, TOA or TDOA measurement of the UWB signal is applied to obtain the location of the target [Fischer et al. 2010;Zhang et al. 2006]. While NLOS is a challenge for UWB indoor positioning, a novel probabilistic TDOA model is proposed to accommodate this NLOS in Prorok et al. [2011]. ...
With the marvelous development of wireless techniques and ubiquitous deployment of wireless systems indoors, myriad indoor location-based services (ILBSs) have permeated into numerous aspects of modern life. The most fundamental functionality is to pinpoint the location of the target via wireless devices. According to how wireless devices interact with the target, wireless indoor localization schemes roughly fall into two categories: device based and device free. In device-based localization, a wireless device (e.g., a smartphone) is attached to the target and computes its location through cooperation with other deployed wireless devices. In device-free localization, the target carries no wireless devices, while the wireless infrastructure deployed in the environment determines the target’s location by analyzing its impact on wireless signals.
This article is intended to offer a comprehensive state-of-the-art survey on wireless indoor localization from the device perspective. In this survey, we review the recent advances in both modes by elaborating on the underlying wireless modalities, basic localization principles, and data fusion techniques, with special emphasis on emerging trends in (1) leveraging smartphones to integrate wireless and sensor capabilities and extend to the social context for device-based localization, and (2) extracting specific wireless features to trigger novel human-centric device-free localization. We comprehensively compare each scheme in terms of accuracy, cost, scalability, and energy efficiency. Furthermore, we take a first look at intrinsic technical challenges in both categories and identify several open research issues associated with these new challenges.
... For mobile robot tracking, Segura et al., proposed a novel UWB navigation system for the indoor environment that employs a TOA based estimation algorithm to accurately locate the mobile robot [48]. Fischer et al., designed a monolithic integrated transceiver chipset for UWB to use in indoor localization systems where TOA techniques have been used for position estimation [61]. The system was implemented for line-of-sight environments, and its accuracy was estimated to be 8.3 cm. ...
In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB) is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT) to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space.
... For mobile robot tracking, Segura et al. proposed a novel UWB navigation system for indoor environment, which employ a TOA based estimation algorithm to accurately locate mobile robot [12]. Fischer et al. designed a monolithic integrated transceiver chipset for UWB to use them in indoor localization systems where TOA techniques have been used for position estimation [27]. The system was implemented for Line-of-Sight environment and its accuracy was estimated to be 8.3 cm. ...
In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. To cope with this surge of interest, much research effort has focused on meeting the needs of these applications and overcoming their shortcomings. Ultra WideBand (UWB) is an important technology in the field of indoor positioning and has shown great performance compared to others. In this work, we identify and analyze existing ultra wideband positioning technologies and present a detailed comparative survey. We also provide a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis, a method generally used in management science to evaluate the strengths, weaknesses, opportunities, and threats involved in a product or technology, to analyze the present state of UWB positioning technologies.
... Localization in time of arrival (TOA) systems is mathematically simple, however, it requires ever, perfect synchronization between MU and APs. As such a global synchronization is hard to realize[36], many experimental systems make use of the two-way ranging approach[23],[26],[40]. In this scheme, the MU sends an information to a selected AP and measures the time elapsed until it answers. ...
... The UWB physical layer, described in the 2007 amendment to the standard [13], has been analyzed in depth by the research community; timestamp perfomance of low cost, full analog, custom UWB device can reach standard deviation of tens of femtoseconds on short observation windows (e.g 10 ms), while over longer observation time (e.g. > 1 s) the standard deviation grows in the range of picoseconds, as confirmed by [8] [25]. Commercially available transceivers for localization (e.g. ...
Network time distribution relies on timestamping, which is employed by local nodes to assign a time value to incoming timing packets. Clearly, any error affecting the timestamp has a direct impact on the final synchronization accuracy of the system. In wireless sensor networks (WSNs), impairments affecting the wireless physical layer are the primary cause of such timestamping errors, and it would be advantageous to flag suspect timestamp values before feeding them into a synchronization algorithm. This paper discusses a new strategy for validating timestamps in a WSN based on IEEE 802.15.4 chirp spread spectrum. The considered system employs physical-level timestamping, which generates one timestamp for each symbol belonging to a packet. Such set of timestamps is processed using a Kalman filter (KF) that compares them with predicted values, employing statistical thresholds referred to the KF innovation process. Experimental results obtained over a long observation period shows that even in a noisy environment with several interfering communication sources, the algorithm is able to detect untrusted timestamps.
... i.e., the actual lower bound for synchronization accuracy in the proposed solution. For the sake of completeness, it must be highlighted that these results are in good agreement with those obtained using UWB radios developed in the PULSER II European project [48], where a more complicated and expensive approach was used. ...
Wireless sensor networks are becoming widely diffused because of the flexibility and scalability they offer. However, distributed measurements are significant only if the readout is coupled to time information. For this reason, network-wide time synchronization is the main concern. The objective of this paper is to exploit a very simple hardware implementation of an IR-UWB radio for realizing an accurate synchronization system for wireless sensors. The proposed solution relies on commercial-off-the-shelf discrete electronic components (rather than on specialized transceivers). It is designed for providing accurate timestamping of the packet time of arrival (TOA) to an adder-based tunable clock, which tracks the network time reference. The comprehensive set of experimental results based on prototypes, shows a TOA detection error with a standard deviation well below 1 ns. On the other hand, in the FPGA-based prototype, the synchronization performance reaches an overall synchronization error of few nanoseconds. Finally, in order to highlight the tradeoff between timestamping accuracy, clock stability, and synchronization performance, some additional simulations have been carried out: a synchronization error in the order of 1 ns is possible, if good local oscillator sources are available in the nodes and if the adjustable clock has a sufficient resolution.
... Another prevailing feature of IR-UWB is its shortest latency amongst others which can guarantee it huge application potential for indoor localisation and delay sensitive communications. With IR-UWB very accurate localisation in the range of few cm is possible [10]. This work concentrates on the implementation of the standard IEEE802.15.4a based on IR-UWB. ...
One energy efficient way of ASIC implementation for the standard IEEE802.15.4a was considered in greater detail. The main focus was on developing a solution for short range communication based on impulse radio ultra wideband. The ASIC implementation is performed with the 250 nm SiGe technology from IHP, Germany. The current system consists of three chips: radio frequency frontend, digital baseband and an integrating analogue digital converter. All the chips were fabricated and designed at IHP. A non-coherent energy detection receiver was realised which collects energy over 16 ns in analogue fashion. The performance of the complete system was evaluated bringing the chips on a board. Our multiple ASIC approach was a necessary step towards a complete integration of the system into a single chip. This paper discusses the function of individual chips and their interaction on a board. The performance was assessed by frame error rates, approximate coverage and waveforms at certain points. Initial laboratory tests and measurements suggest that the implemented system can support wireless communications in a distance of up to five meters and consume reasonable power.
... In this case, the MU receives back the transmitted signal, in addition containing the information from which AP (coordinates) it came. In this concept the MU has to calculate its own location, based on relative distance information to the reference nodes (APs) [8, 9]. This is based on the two-way-ranging measurement prin- ciple. ...
A complete impulse-based ultrawideband localization demonstrator for indoor
applications is presented. The positioning method, along with the method of positioning error
predicting, based on scenario geometry, is described. The hardware setup, including UWB
transceiver and time measurement module, as well as the working principles is explained. The
system simulation, used as a benchmark for the quality assessment of the performed
measurements, is presented. Finally, the measurement results are discussed. The precise analysis
of potential error sources in the system is conducted, based on both simulations and
measurement. Furthermore, the methods, how to improve the average accuracy of 9 cm by
including the influences of antennas and signal-detection threshold level, are made. The
localization accuracy, resulting from those corrections, is 2.5 cm.
... There are two ways of performing the TDoA measurement in a system consisting of multiple APs and MUs: 1) either the MUs send the UWB pulses and, based on the user specific code, they will be localized by a central processing unit, collecting the data from the APs, 2) or the APs will be used only as repeaters, sending the signal back to the MU, including the information about its own position. In this concept the MU has to calculate its own location based on time information[1]. This is based on two-way-ranging principle. ...
In this work a complete Ultra-Wideband localization demonstrator for indoor applications is presented. The hardware setup, including UWB transceiver and time measurement module, as well as the working principles are explained. The positioning method, along with the method of positioning error predicting, based on scenario geometry, is described. The system simulation is presented, that is used as a benchmark for the quality assessment of the measurements performed later on. Finally, the measurement results are presented and discussed. The precise analysis of potential error sources in the system is conducted based on both simulation and measurement. Furthermore, suggestions how to improve the achieved average accuracy of 3.6 cm are made.
This paper discusses two ways of measuring the distance between the transmitter and the receiver using UWB technology, then identifies their advantages and disadvantages. The method of calculating the position is presented together with the method of predicting errors based on room geometry. The hardware configuration of the transmitter and receiver systems included in a location system based on UWB technology is explained. Bluetooth technology is discussed, which is used to connect the location system with the environmental monitoring system.
This paper describes a localization method for an IR-UWB (Impulse Radio Ultra Wideband) two-way ranging system developed for precise time-of-arrival measurements. The ranging system provides a time resolution of 275 ps, which allows precise indoor distance estimation with the accuracy of ±4 cm. In this work, a two-way ranging algorithm has been extended into a localization algorithm without the need to adapt the hardware. The localization algorithm has been implemented in the FPGA and applied to the IR-UWB ranging system. The main advantages of such a localization algorithm is the simple implementation the scalability and the robustness of the communication between multiple devices.
This paper describes a monolithic integrated single-chip transceiver intended for impulse radio (IR) - Ultra-wide Band (UWB) applications compliant to the IEEE 802.15.4a standard. The transceiver operates in the higher UWB band on the mandatory channel #9 (7.9872 GHz). The implemented nominal data rate is 850 kb/sec. The presented chip consists of the entire RF-front-end, 6-bit-resolution successive approximation register (SAR) analogue-to-digital converter (ADC), and the baseband processor running with a clock of 31.2 MHz. The analogue frontend can be further segmented into a pulse generation and transmit part and a quadrature direct down conversion receiver part, whereas both parts share a frequency synthesizer based on an integer-N phase-locked loop (PLL). The impulse generation is based on the gated oscillator principle allowing required on-off keying (OOK) as well as binary phase shift keying (BPSK). While the receiver supports both, coherent and non-coherent impulse detection, here only non-coherent operation will be presented. The baseband processor part contains a separated 499.2 MHz clocked block for transmitter control and provides a serial peripheral interface (SPI) for data exchange with an external micro controller. The presented chip was fabricated in a 0.25 μm SiGe:C BiCMOS technology occupying a Si area of 3.25 - 3.25 mm2.
This paper describes a monolithic integrated transmitter intended for impulse radio (IR) Ultra-wide band (UWB) indoor communication and indoor localization. The transmitter operates in the higher UWB band centered at 7.25 GHz and generates impulses with bandwidth of 2.08 GHz. Consequently, the transmitter utilizes for communication and ranging complete UWB band assigned for Europe. The average pulse repetition frequency of 56.64 MHz and a 3-bits pulse position modulation (8-PPM) provides data rates up to 169.92 MBit/sec. Additionally, the driver amplifier with a fast switchable current bias is introduced into the transmitter for power efficient operation. The switch-on time of the bias is equal to 8ns. Besides the communication capability, an advanced time-of-arrival measurement extension is implemented in the transmitter. It runs with the clock of 3.625 GHz and allows the distance measurements with an accuracy of 275 picoseconds (translates to ranging accuracy of approximately 8.3 cm).
Design, simulation, implementation and performance of IR-UWB baseband conforming to IEEE802.15.4a are discussed. The baseband can support various data rates such as 850 Kb/s, 6.81 Mb/s and 27.24 Mb/s. The design and parameter selection were considered carefully taking into account all possible imperfections that IR-UWB high frequency signal can experience. Energy detection receiver employing a comparator clocked at 499.2 MHz was adopted for the digitisation. Using I and Q path both positive and negative pulses were detected with a high reliability leading to a very good synchronisation performance. Simulation results confirm that the synchronisation is very robust being always correct for office NLOS environment and a large clock deviation between transmitter and receiver. The algorithm presented in this paper was implemented with discrete components, FPGA and signal generators. Experimental results show a good agreement with the simulation for all the data rates and the implemented baseband offers around six meter communication range tested along with a high frequency frontend from discrete components.
We present a Bluetooth indoor localization system, which is intended to have an accu-racy of ±1 meter. The major advantage compared to all disclosed systems is the ability to locate any mobile Bluetooth device without additional hardware in the mobile and without any changes in its software. The basic idea of the system is the measurement of time differences of arrival of a signal sent by the mobile to stationary installed base stations. We show first meas-urement results achieved with a simplified demonstration setup showing meter position accu-racy. The demonstration setup consists of a moving transmitter and two stationary time meas-urement stations including a receiver, a correlation IC and a microcontroller.
In this paper we present ULANDreg testbed that consists of two European mask compliant impulse radio ultra-wideband (IR-UWB) transceivers with low data rate and medium range for data communication and distance measurement. The transmitter uses time hopping spread spectrum codes to reduce the peak to average ratio in the power spectral density and the receiver is based on a filter bank. The hardware/software partitioning of the receiver provides the testbed with the necessary flexibility. Therefore new ranging algorithms can be tested quickly in real time in order to improve the distance measurements. The ranging protocol performs the distance calculation with four-way exchange of the frame even when there is not a common timing reference between transceivers. The algorithms demodulate data and estimate relative time of arrival (RTOA) in a line of sight (LOS) and non-LOS (NLOS) framework. Finally, distance measurement results are presented showing the functionality of the testbed.
Impulse-radio (IR)-based ultra-wideband (UWB) technology is a strong candidate for short-range data communication and positioning systems. This paper examines the performance of time-of-arrival (TOA) position estimation techniques as well as the simulated and measured performances of an IR-UWB noncoherent energy-collection receiver. The noncoherent IR-UWB transceiver has been designed for operation over the frequency range 3.1-4.1 GHz and implemented in 0.35-μm SiGe BiCMOS technology. The performance of two different algorithms, namely, the threshold-crossing and the maximum selection (MAX) algorithms, are compared in terms of TOA estimation error in Saleh Valenzuela channel model 3 and channel model 4. The implemented structure of the TOA MAX algorithm suitable for IR-UWB-based noncoherent receivers is presented. A UWB testbed has been constructed in order to test and measure the transmitted waveform as well the receiver performances. The simulated receiver noise figure is 7.3 dB while the receiver gain is 34 dB. The TOA MAX algorithm can achieve ±5-ns positioning accuracy for 95% of cases. Constant transconductance tuning circuits for improved TOA estimation reliability are also presented.
Ultra Wide Band (UWB) wireless communications offers a radically different approach to wireless communication compared to conventional narrow band systems. Global interest in the technology is huge. This paper reports on the state of the art of UWB wireless technology and highlights key application areas, technological challenges, higher layer protocol issues, spectrum operating zones and future drivers. The majority of the discussion focuses on the state of the art of UWB technology as it is today and in the near future.
Until UWB became a widely spread subject of research, wireless telecommunications applications were driven by the need to make highly efficient use of spectrum resources, that existed only in scarce quantities. In order to avoid "chaos" in the few allocated frequency bands, standards relying much on the central management of the available resource were considered the appropriate regulative. However, it turned out that there are complex technical and acceptance problems to be solved in the attempt to spectrally and temporally manage wireless applications of the most different kind. Enabled by the UWB regulatory provisions, the paper introduces an alternative approach to spectrum access which gives increased independence to applications and users.
This paper introduces a novel MAC strategy, which flexibly configures the error protection level and the average pulse period per link to control the shared medium utilization in an IR-UWB network. This strategy deviates from recent research efforts towards access schemes based on IEEE 802.15.4 MAC and exploits research results of game theory and cognitive radio.
This paper describes a monolithic integrated transmitter intended for impulse radio (IR) Ultra-wide band (UWB) applications including indoor communication and indoor localization. The transmitter operates in the higher UWB band centered at 7.68 GHz and it is optimized for a pulse bandwidth of about 1.5 GHz. The transmitter generates single pulses with a repetition rate of 60 MHz and utilizes pulse position modulation (8-PPM) for data communication. A dedicated time-of-arrival (TOA) measurement extension supports precise indoor localization in conjunction with an appropriate UWB receiver. The demonstrated spatial ranging resolution is about 3.9 centimeter under line-of-sight conditions.
This paper describes a monolithic integrated non-coherent receiver intended for impulse radio (IR) Ultra-wide band (UWB) applications including indoor communication and indoor localization. The receiver operates in the higher UWB band centered at 7.68 GHz and it is optimized for a pulse bandwidth of about 1.5 GHz. The overall gain of the receiver amplification chain can be set up to 56 dB in 16 steps via a digital 4-bit interface. A dedicated ldquoleading edgerdquo-detector supports precise indoor localization in conjunction with an appropriate UWB transmitter. A fast comparator indicates the exceeding received signal beyond a threshold set by an internal digital-to-analogue converter (DAC). The circuit was fabricated in 0.25 mum SiGe:C BiCMOS technology.
A UWB radio SoC, including an RF transceiver and a digital PHY, is presented for both communication and ranging. Realized in 0.18 ¿m CMOS, the Tx generates ternary coding and BPSK pulses in the 3-to-5 GHz range, and the Rx achieves a data rate of 0.25 to 20 Mb/s, a noise figure of 7.2 to 8.4 dB, and a sensitivity of -82 to -90 dBm. At 1 Mb/s, only 0.92 nJ/b and 5.3 nJ/b are required for Tx and Rx. Ranging accuracy of <15 cm is realized.
Scalable Low-Power High-Speed BiCMOS ECL Library
- H Gustat
- G Kell
Ultra Wideband : Technology and Future perspectives Available: http://www.wireless- worldresearch.org/fileadmin/sites/default/files/about-the-forum
- B Allen