New TDOA approach using communication signals 

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Wireless display, distribution of HDTV, high quality audio and wireless docking

It has been a while since high data digital video (HDTV) penetrated in almost every home. HD video can be transmitted via cable connections that provide easily very high data rates. However, users would prefer to utilize a wireless solution to reduce the number of visible wires. Flat panel display which can be hanged on a wall, is an example of the need for a wireless video solution. The main applications of this category are [6, 7]:
Desktop storage and display.
Projection to TV or projector in conference room or auditorium.
In-room gaming.
Streaming from camcorder to display.
Outside broadcast pickup.
Video streaming around the home.
Uncompressed baseband high-denition video.
Uncompressed high-quality audio.
Wireless docking is another application of this category which is a combination of wireless display, wireless synchronization and wireless I/O. Let’s consider a scenario where a tablet is wirelessly bridging to a dock that instantly connects the tablet to dierent monitors, keyboard, and mouse. And it is just by putting the tablet in range that connects it to all these peripherals needed to turn it into a full desktop system.

Benets of millimeter-wave frequencies for Gb/s communication

As already mentioned, new applications for WPAN and WLAN require very high data rates and a very high level of QoS (Quality of Service) to meet user expectations.
Millimeter-wave frequencies provide a unique opportunity to wirelessly enable these applications. Dierent approaches are being pursued to increase the overall wireless access network capacity and the maximum supportable data rate. One proposed solution is improving spectral eciency, which requires individual radio link optimization simultaneously for many users [3, 4]. To implement this approach, one should deal with challenges like self-interference by adjacent cells and imperfections of the deployed hardware.
This requires advanced and complex signal-processing techniques and high performance transceivers, which is neither easy nor always possible to achieve. The second solution is network densication (spectrum reuse) by reducing distance between base stations. This is an energy ecient solution but with more inter-cell interference, thus more complexity. The third solution is spectrum extension using millimeter-wave communications. Below 6 GHz, its dicult to allocate additional spectrum in low frequency because of satured existing frequency allocations. So, the solution could be utilizing higher frequencies like millimeter-wave bands. The large amount of radio spectrum available, combined with low cost CMOS (Complementary Metal Oxide Semiconductor) technology and new solutions of integrated antennas, make millimeter-wave spectrum a valuable candidate for new capabilities for future wireless communication networks. Advantages of using millimeter-waves regarding capacity increase techniques are shown in Figure 1.3.
Spectrum extension by means of millimeter-wave cellular overlay perfectly consistent into existing networks. Millimeter-waves normally oer a large bandwidth and a shorter range communication which leads respectively to densication of networks and more throughput. They also use beamsteering and multi-user MIMO techniques supporting point to point and point to multi-point communications which increase the spectrum ef-ciency (Figure 1.3). Using the large bandwidth available at frequencies in the 30{300 GHz range can lead to extend the spectrum. Recently, 28 and 38 GHz bands (where 1 GHz of bandwidth is available) have been explored in details to overcome the problem of future network capacity. 60 GHz band and the E band (71{76 and 81{86 GHz) are also among the bandwidths explored recently to provide multi-Gbps capacity for wireless communications.

Lower energy consumption thanks to high data rates

It may seem against the intuition to reach a low power device by using high-frequency, high-throughput wireless technologies. But, one should consider the fact that the suitability of a design for mobile applications is determined by the energy eciency and not just the instantaneous power consumption. On the rst look, it may seem that a typical high data rate 60 GHz wireless design consumes more power than other wireless technologies over higher distances. But this conclusion is misleading due to the fact that the total power consumption may be reduced by using a higher speed solution because of its ability to operate at a much lower duty cycle than slower radio technologies. Considering this fact, the power eciency is determined by the energy required per bit transmitted. Then, in this case, the faster the radio technology, the lower the actual duty cycle and the lower the amount of energy necessary to transfer each bit of data. Furthermore, the overall power drain is reduced by using the host processor and storage for a shorter period of time [7]. In addition, a high throughput system decreases the time required to complete a transaction and enables the user to quickly accomplish the data transfer. Therefore, using a high throughput communication at 60 GHz is helping to achieve an efficient energy consumer system. Even without considering duty cycle, higher bandwidths and higher data rates lead to better efficiencies. In fact it can be seen from Figure 1.6, that applying more bandwidth per communication link is a significant contributor for improved energy efficiency measured in Bits-per-Joule [21].

Integrated circuit technology and RF 60 GHz components

A demand for high-speed wireless connections and recent progress in silicon-based technologies have driven the development of wireless local area networks (WLANs) standards operating at 60 GHz such as WiGig [14, 36]. Such applications require a low-cost and low-power implementation, which leads to implement system-on-chip for the transceivers and use of advanced CMOS nodes. The choice of integrated circuit (IC) technology depends on:
Implementation aspects: Issues such as power consumption, eciency, dynamic range, linearity requirements are among implementation aspects.
System requirements: Issues such as transmission data rate, modulation scheme, cost and size, transmit power, bandwidth are related to system requirements. At mm-wave, there are three competing IC technologies:
Gallium Arsenide (GaAs) and Indium Phosphide (InP) technology: GaAs technology oers low noise, fast and high gain implementation but suers from poor integration and expensive implementation.
Silicon Germanium (SiGe) technology such as Heterojunction Bipolar Transistor (HBT) and Bipolar junction transistor and CMOS (BiCMOS): SiGe technology allows low noise, fast and high gain implementation and is a cheaper alternative to the GaAs.
Silicon technology such as CMOS and BiCMOS: CMOS technology performance is not remarkable considering gain and noise and linearity but it provides cheaper product with a high degree of integration [2].
None of these technologies can meet all the implementation challenges and system requirements mentioned above at the same time. However, it should be considered that the size and cost are the key factors regarding mass deployment and market exploitation. Considering this point of view, CMOS technology is the leading candidate among the others. Recent progress make it possible to obtain thinner CMOS technology such as 28 nm compare to 130 nm in past years [36, 37].
The 5 mm wavelength of 60 GHz allows integration of analog and microwave components and obtaining monolithic microwave integrated circuits (MMICs) onto a single chip or package. CMOS processes have also reached transition frequencies of hundreds of gigahertz [38]. Hence, the performance of 60 GHz system is improved by using multi-chip solutions and mixed signal equalization [39, 40].

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Modulation schemes and MAC protocols

For 60 GHz radio, the choice of modulation scheme relies on:
• the propagation channel
• the use of high gain antenna/antenna array
• the limitations imposed by the RF technology [39-46]
It should be noticed that, although simple modulation schemes such as single carrier (SC) can be used to meet some hardware constraints, they exhibit significantly less spectral efficiency. Hence, to find a robust and permanent solution, these simpler modulation techniques are not the best choice. For frequency selective channels with high multi-path effects, an OFDM is a better choice since it can mitigate the multi-path effects by providing flat fading smaller bandwidths. It is done by dividing the high-rate stream into a set of parallel lower rate sub-streams. Furthermore, using OFDM decreases the complexity of the system for multi-giga-bits systems by simplifying the equalization process. OFDM is also well suited at 60 GHz regarding its ability to decrease ISI (Inter Symbol Interference) effects. But it is sensible to phase noise from inter subcarrier interference (ICI) and requires large PAPRs.

Table of contents :

1 Context and objectives 
1.1 Introduction
1.2 New applications demanding high data rate communications
1.2.1 Wireless networking and instant wireless synchronization
1.2.2 Wireless display, distribution of HDTV, high quality audio and wireless docking
1.2.3 Intelligent transportation systems
1.2.4 Access and future 5G
1.3 High Data rate communication: millimeter-wave solutions (60 GHz)
1.3.1 Benets of millimeter-wave frequencies for Gb/s communication
1.3.2 Why 60 GHz? Regulatory environment 60 GHz implications
1.4 Energy aspects
1.4.1 Lower energy consumption thanks to high data rates
1.4.2 Lower energy consumption thanks to spatial capabilities Beamforming Multi-hops
1.5 The objective: a better utilization of spatial resources
1.5.1 Localization as a support for green radio
1.5.2 Other applications of indoor localization
1.6 Conclusion
2 State of the art of 60 GHz systems and indoor positioning methods 
2.1 Introduction
2.2 60 GHz communication systems
2.2.1 Channel issues Propagation characteristics Material impact
2.2.2 Technological aspects Integrated circuit technology and RF 60 GHz components Antenna
2.2.3 Modulation schemes and MAC protocols
2.2.4 Standards WirelessHD standards IEEE 802.15.3c-2009 standard ECMA 387 WiGig and IEEE 802.11ad
2.2.5 Conclusion
2.3 Indoor positioning methods
2.3.1 Angle related measurements Method utilizing receiver antenna’s amplitude response Method utilizing receiver antenna’s phase response .
2.3.2 Distance related measurements Received Signal Strength (RSS) measurements Time Of Arrival (TOA) measurements Time Dierence of Arrival (TDOA) measurements .
2.3.3 Conclusion
2.4 Conclusion
3 New TDOA approach using communication signals 
3.1 Introduction
3.2 TDOA metric
3.2.1 Conventional TDOA method
3.2.2 New TDOA method
3.2.3 Mathematical analysis and the direct problem
3.2.4 Inverse problem
3.3 TDOA extraction using IEEE 802.11ad standard
3.3.1 Simulation setup Geometry of acquisition SystemVue simulation
3.3.2 TDOA estimation using EVM of received signal Simulation results Conclusion
3.3.3 TDOA estimation using equivalent channel response (ECR) . Simulations results TDOA estimation Conclusion
3.3.4 Multi-band approach
3.4 Limitations and validity domain
3.4.1 Channel consideration Simple multi-path in uence on 60 GHz TDOA estimation using EVM IEEE channel in uence on 60 GHz TDOA estimation using ECR
3.4.2 Quality of communication
3.5 Conclusion
4 Measurements and experimental results 
4.1 Introduction
4.2 Measurements using VNA
4.2.1 Experimental setup and test conditions
4.2.2 Results
4.2.3 Conclusion
4.3 Measurements using Vubiq and VSA
4.3.1 Experimental setups Arbitrary waveform generator (AWG) 60 GHz waveguide module development system (V60WGD02) SystemVue interface
4.3.2 Measurements results Free space measurements Guided mono-band measurements Guided multi-band measurements
4.4 Measurements using Highrate transceiver
4.4.1 Experimental setup and test condition
4.4.2 Results
4.5 Multi-band measurements with base-band signals
4.6 Conclusion
Conclusion and perspectives
Appendix A: 60 GHz Vubiq Modules
Appendix B: Highrate Transceiver
Appendix C: List of publications


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