**Author details**

Mohamed El-Hadidy, Mohammed El-Absi and Thomas Kaiser *Duisburg-Essen University, Institute of Digital Signal Processing (DSV), Germany*

*Karlsruhe Institute of Technology, Institut für Hochfrequenztechnik und Elektronik (IHE), Germany* Yoke Leen Sit and Thomas Zwick

Markus Kock and Holger Blume *Leibniz Universität Hannover, Institute of Microelectronic Systems (IMS), Germany*

### **10. References**

18 Will-be-set-by-IN-TECH

iterations. Figure 12 summarizes the estimated number of operations for the computation of a set of **V** and **U** matrices, based on well-known optimized hardware implementations. Comparing the iterative approach computational complexity to the the closed-form 2x2 IA implementation presented in Section 8.3, the number of operations is increased by a factor of

IA is a promising approach for communications with numerous pairs of users. In our contribution we have investigated the usefulness of IA for MIMO UWB communication systems. Beside apart of the significant power processing needed for the high data rate applications, the MIMO UWB antenna design remains a challenge. The antenna synthesis presented here can be viewed as synthesizing an antenna system with optimal radiation pattern catered towards an intended scenario. This antenna system radiates orthogonalized channels (after the averaging strategies) with sufficient power and has fixed beamforming (direction optimized according to the scenario and with averaging over various positions) at the transmitter and receiver antenna systems. Also, the resulting system has been simplified to 2 inputs and 2 outputs based on the subchannels with the strongest power. The whole system has been simulated by an indoor ray tracing tool and the corresponding MIMO UWB base band modulation schemes and detection techniques. Moreover, an antenna selection method is proposed in order to increase the robustness of IA in real environments. It is demonstrated that by using orthogonal multimode antennas a significant gain can be obtained. In the third and last part of our contribution the hardware efforts of IA algorithms are studied in more detail. It is worked out that highly challenging system blocks like IA can be elaborated today only by the help of suitable hardware emulation platforms which are typically FPGA-based. Therefore, a generic methodology has been elaborated and implemented which allows to explore the implementation design space. The hybrid hardware-in-the-loop research and design space exploration (DSE) framework created in this work combines high-level tools (e.g. Matlab/Simulink) and optimized hardware blocks. The properties of the elaborated optimized on-chip infrastructure template make it suitable for usage in final ASIC targets and thus enable the test, debugging and characterization of signal processing blocks in their target environment. This DSE framework has been used to derive cost models for K-user iterative IA algorithms. Estimates for the implementation effort (e.g. in terms of operation counts in dependency of the number of users) have been derived. Because of this project, a generic DSE framework is available and can be used to work out suitable architectures for further

approximately 60.8.

**9. Conclusion**

challenging building blocks.

Markus Kock and Holger Blume

Yoke Leen Sit and Thomas Zwick

Mohamed El-Hadidy, Mohammed El-Absi and Thomas Kaiser

*Duisburg-Essen University, Institute of Digital Signal Processing (DSV), Germany*

*Leibniz Universität Hannover, Institute of Microelectronic Systems (IMS), Germany*

*Karlsruhe Institute of Technology, Institut für Hochfrequenztechnik und Elektronik (IHE), Germany*

**Author details**


20 Will-be-set-by-IN-TECH 152 Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications **Chapter 8**

*on Wireless Communications Technologies and Software Defined Radio (SDR-WInnComm 2012)*, Washington, DC, USA. Accepted for publication.

**Antennas and Propagation for On-, Off-**

de-embedding i.e. to separate the antenna form the underlying channel.

The ultra-wideband technology seems very attractive to be transferred to the challenging field of body centric communications. This technology involves the potential to establish robust communication links or high resolution localization systems. All these applications require a characterization of the propagation channel and the influence of the corresponding user to the system performance. Due to the inevitable interaction between the antenna and the related propagation channel a separation of both characteristics via traditional antenna theory methods is hardly applicable. The scope of this study is to establish a so called antenna

**Chapter 7**

Traditional antenna parameters (e.g. directivity, gain, effective area) are based on free space propagation conditions. Underlying is the well known model of an isotropic radiator which enables the separation of channel, transmitter and receiver. It will be shown that this theory can be adapted to deduce approximations of equivalent antenna parameters for body centric communications. Key factor of this approach is the development of equivalent far field models of the corresponding in- and on-body scenarios. For off-body scenarios the propagation direction points away from the human body. The matching and the radiation pattern of the respective antennas may change due to the interaction with the human body but in general no modifications of the far field model are necessary. Therefore, the traditional theory is applicable with just minor restrictions and will not be discussed in further detail here.

The study is structured in two sections. The first part focuses on an in-body link i.e. the main propagation path of the electromagnetic wave leads through the tissue of the human body. Typical applications for this scenario are medical implants like wireless endoscopy or the RF breast cancer detection systems. The second part characterizes an on-body link. This means that the propagation path is defined along the body surface and the antenna is located in close proximity of the human body. The universality of this theory will be shown for the

> ©2013 Grimm and Manteuffel, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original

©2013 Grimm and Manteuffel, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

**and In-Body Communications**

Additional information is available at the end of the chapter

characterization of an UWB teardrop antenna.

work is properly cited.

Markus Grimm and Dirk Manteuffel

http://dx.doi.org/10.5772/55080

**1. Introduction**


152 Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications **Chapter 8 Chapter 7**
