Citation Context

...the generation of frames which are then transmitted using the WARP hardware or capture of signals using the FPGAs populating the WARP boards. Indicative prototyping results are the full-duplex scheme =-=[54]-=- and MU Beamforming (MUBF) [55] for WLAN systems. Similarly, off-line prototyping efforts are also reported by both HHI [56]1, related to interference management in a frequency reuse scheme, and ETH [...

Citation Context

...are then transmitted using the WARP hardware or capture of signals using the FPGAs populating the WARP boards. Indicative prototyping results are the full-duplex scheme [54] and MU Beamforming (MUBF) =-=[55]-=- for WLAN systems. Similarly, off-line prototyping efforts are also reported by both HHI [56]1, related to interference management in a frequency reuse scheme, and ETH [57], regarding the compensation...

Citation Context

...] and MU Beamforming (MUBF) [55] for WLAN systems. Similarly, off-line prototyping efforts are also reported by both HHI [56]1, related to interference management in a frequency reuse scheme, and ETH =-=[57]-=-, regarding the compensation of residual transmit signal impairments. A major reference in the off-line-based rapid prototyping methodology is found in the Vienna MIMO testbed. The latter was used to ...

Citation Context

... MIMOOFDM IP library: the provided baseband designs are oriented towards a modelbased design flow (i.e., schematic-entry design), while a software-implementation of the MAC layer is also contemplated =-=[31]-=-. Department of Electronics and Systems, Universidade da Coruña (A Coruña, Spain) The contributions found in the literature produced by the Group of Electronic Technology and Communications (GTEC in s...

Citation Context

...tment of Electrical and Computer Engineering, Rice University (Houston, Texas, United States of America) Rice University is the birthplace of the popular Wireless Open-Access Research Platform (WARP) =-=[30]-=-, an advanced FPGA-based experimental testbed which allows the prototyping of advanced wireless communication systems. The WARP framework provides an open-access repository comprising a basic MIMOOFDM...

Citation Context

...d in off-line testbeds is their ability to realistically assess the performance of a wide variety of PHY-layer schemes: Time Division Duplex (TDD) zero-forcing linear precoding for OFDM-based systems =-=[49]-=-, standardcompliant MIMO-OFDMA mobile WiMAX receivers [50, 51] or Coordinated Multi-Point (CoMP) for LTE-based systems [52]. A popular initiative towards this end is provided by the openly accessible ...

Citation Context

... communication, as illustrated in Figure 1.2. Two indicative standard1 Chapter 1: Introduction 2 Figure 1.1: Relevant summary statistics on the annual growth of factors contributing to data explosion =-=[1]-=-. ization initiatives towards 4G wireless communication are the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), with its latest revision LTE-Advanced, and the Worldwide Interopera...

Citation Context

...HY-layer is controlled by the MAC layer depending on the observed packet-loss. More interestingly, fundamental HW/SW co-design notions enabling an efficient PHY/MAC cross-layer design are reported in =-=[84]-=-, enabling the design and implementation of a distributed cooperative MAC and OFDM-based PHY layer. A similar architecture is presented in [85] by the GTEC-group, where it is described the development...

Citation Context

...the cost of implementing such techniques before entering into a true VLSI implementation. Indicative related work in this sense is a fullyparallel Low-Density Parity Check (LDPC) decoder presented in =-=[116]-=-, a lowpower synchronization technique for WiMAX systems described in [117] and a high-throughput iterative MIMO detection detailed in [118]. Relation to the work presented in this thesis: the present...

Citation Context

...er software constructs; the HLS capabilities of the EDA tool automatically translate this model to HDL code. Two indicative use cases of the WARP platform implement a cooperative OFDM-based PHY-layer =-=[95]-=- and a MIMO LTE receiver [96]. It should be noted that few design details are usually provided in the encountered references, where the focus is generally laid on the experimental verification of adva...

Citation Context

...atter is especially important when dense FPGA implementations are struggling to meet timing constraints. A very representative example of this design approach is provided by researchers of the ETH in =-=[105]-=-, where it is detailed a complete 4x4 MIMO WLAN PHY-layer prototyping effort featuring a hardware-efficient design, mapped to a multi-FPGA implementation and validated by experimental means. Other sim...

Citation Context

...feedback link from the receiver to the trasmitter. Essentially, three main approaches have been proposed in the literature to realistically measure the performance of the previously mentioned systems =-=[11]-=- : (i) Off-line testbeds where the feedback is carried out via a high-speed connection. The round trip times of a typical hardware-setup (e.g., considering an off-line execution of a MATLAB-based PHY-...

Citation Context

...e restrictions that apply: only very limited language constructs and specific functions or routines can be automatically translated into an HDL description, and often not with a very efficient result =-=[23, 24]-=-. Additionally, the automated HDL code generation suffers in the translation of the floating-point arithmetic to a limited dynamic range. In other words, it is frequent the requirement to predetermine...

Citation Context

... implementation of the PHYlayer by utilizing both HLPL-based and FPGA-realized processing blocks (e.g., combined with a software-based MAC layer). An illustrative example of such approach is given in =-=[86]-=- where different HW/SW partitions are analysed to improve the decoding rate of a MIMO sphere decoder. Similarly, a reconfigurable mobile WiMAX PHY-layer implementation is presented by the GTEC-group, ...

Citation Context

...is still very high (i.e., it largely depends on the desired precision and statistical accuracy of the simulation results, the selected bandwidth, the transmission mode and the chosen modulation order =-=[10]-=-). Hence, the number of frames that can be simulated is limited. Moreover, as the physical implementation of complex Chapter 2: The PHY-layer development ecosystem 17 Figure 2.2: Generic off-line prot...

Citation Context

...475T) GPU (NVIDIA GTX480) (b) GPU vs. FPGA performance comparison when implementing a dense linear system solver [20]. (c) Energy consumed by GPP, GPU and FPGA devices in a sliding-window application =-=[21]-=-. Figure 2.6: Recent implementation technology comparison studies. ergy consumption). FPGAs constitute the ideal entry-point to a HW/SW co-design solution. Modern FPGA devices offer the flexible (and ...

Citation Context

... (e.g., for performance and/or enChapter 2: The PHY-layer development ecosystem 24 (a) Computational density (in giga operations per second) per watt of modern fixed- and reconfigurable-logic devices =-=[19]-=-. 23 38 52 63 32 35 48 71 Precision (Mantissa Size) G Fl op s Performance comparison FPGA (Xilinx XC6VSX475T) GPU (NVIDIA GTX480) (b) GPU vs. FPGA performance comparison when implementing a dense line...

Citation Context

...ly compare their algorithms. Some indicative use cases of this simulation framework are interference management in a MU MIMO scenario [43], optimal power distribution among pilot and data subcarriers =-=[44]-=- and Signal-to-Interference-Plus-Noise Ratio (SINR) prediction in a multi-cell scenario [45]. Similarly, an extension to the widely used NS-2 network simulator in order to include a cooperative OFDM P...

Citation Context

... to the widely used NS-2 network simulator in order to include a cooperative OFDM PHY-layer is proposed and verified based on a real-time implementation over the WARP testbed in [46]. Furthermore, in =-=[47]-=- the large scale wireless emulation platform provided by the OpenAirInterface is used to simulate a MU LTE-based frequency reuse scenario. In another case, a channel model derived from experimental da...

Citation Context

...otyping platform. For instance, in [62] the performance of a Bit Interleaved Coded Modulation (BICM) scheme is evaluated under realistic channel conditions. Similarly, the GTAS-testbed is utilized in =-=[63]-=- for the experimental characterization of 4x4 MIMO channels. Furthermore, a very powerful off-line prototyping platform is resulting from the connection of both testbeds. Two illustrative use cases ar...

Citation Context

...evision LTE-Advanced, and the Worldwide Interoperability for Microwave Access (WiMAX), through its evolved WiMAX-2 specifications (Institute of Electrical and Electronics Engineers - IEEE - 802.16.m) =-=[2]-=-. In spite of the ambitious requirements defined for 4G systems, future applications will continue impulsing the evolution of both mobile devices and service infrastructures, imposing demands that now...

Citation Context

...st, the high-level model is exported to C-code (e.g., by using the Simulink Coder TM [SCD]). Then the C-to-HDL synthesis can be applied using both vendor-provided [SCC,CAC,VSL] or academic-originated =-=[25]-=- software tools. Nevertheless, this automatic hardware mapping process is not always entirely seamless, as the generated C-code might contain unsupported constructs (e.g., pointers, floating-point com...

Citation Context

... the Vienna and the Rice University groups. More specifically, a preliminary implementation of a sphere decoder is described in [77] and a GPU-based reconfigurable soft-output detector is detailed in =-=[78]-=-. Relation to the work presented in this thesis: the encountered nonChapter 3: Related work and contribution 47 HDL initiatives, summarized in Table 3.4, include real-time implementations of high-perf...

Citation Context

...nced wireless communication systems implemented by the HHI-group are based on a well defined HW/SW co-design strategy, which takes advantage of the virtues of both FPGA and DSP processor technologies =-=[88]-=-. Although a custom design of the baseband is mentioned in many of the encountered papers, the details of the implemented PHY-layer are never uncovered. It seems reasonable to relate the black-box nat...

Citation Context

...it er at ur e. Chapter 3: Related work and contribution 54 Other related examples include a fixed-complexity high-throughput MIMO detector [99], a configurable sphere detector for MU-MIMO SDR systems =-=[100]-=-, a soft-output detection with turbo decoding [101], a robust channel estimator [102], MIMO-OFDM based channel coding and interleaving techniques [103] and a dynamic spectrum allocation algorithm for ...

Citation Context

... HW/SW co-design solution. Modern FPGA devices offer the flexible (and relatively low-cost) means for the realization of efficient dedicated hardware designs requiring of massive parallel computation =-=[15, 16]-=-. Moreover, many recent studies have shown that (when properly utilized) they are capable of outperforming the advanced non-HDL implementation technologies by providing higher performance and/or energ...

Citation Context

...f both testbeds. Two illustrative use cases are the evaluation of advanced channel estimation schemes for MIMO systems [64] and the validation of interference-alignment techniques for MU MIMO systems =-=[65]-=-. Finally, a measurement-based infrastructure recently deployed by TU Wien aims at assessing the real-world performance of the IEEE 802.11p standard [66]. Relation to the work presented in this thesis...

Citation Context

...t type of commonly encountered HW/SW co-design research works is featuring a FPGA-based PHY-layer implementation which is controlled by a software-based MAC layer. An illustrative example is given in =-=[82]-=- where a programmable OFDM-based PHY-layer targeting SDR applications is presented. The WARP platform provides, among other important contributions in the field, a notable HW/SW co-design approach. Fo...

Citation Context

...ed include the full frequency reuse (and extended coverage) by employing indoor relaying [89], interference management through CoMP joint transmission [90] and interference-aware scheduling in the DL =-=[91]-=-. Finally, the last identified HW/SW co-design approach is centred around the design and implementation of an embedded FPGA-based processor, which could be configured to serve the needs of different D...

Citation Context

...idated by experimental means. Other similar WLAN-based developments have also been found in the literature. The authors in [106] implement a Space-Time Block Code (STBC)-based MIMO scheme, whereas in =-=[107]-=- a Transmit Antenna Selection (TAS) configuration is developed. A DSP-block re-utilization for a minimized hardware cost is presented in [108] and a spectrum-aware adaptive subcarrier allocation in [1...

Citation Context

...e iterative MIMO decoding [110], STBC MIMO decoding [111], autocorrelation-based OFDM signal detection for CR systems [112], reconfigurable twodimensional pipeline FFT processor for MIMO OFDM systems =-=[113]-=-, fixed sphere decoder [114] and 2-phase channel estimation for mobile WiMAX receivers [115]. An important point that has to be underlined is that the extremely demanding bit-intensive computation of ...

Citation Context

...ally-available DSP-specialized FPGA-resources (i.e., dedicated Arithmetic Logical Units - ALUs - embedded at silicon-level) the HDL-defined processors can efficiently implement baseband DSP functions =-=[17, 18]-=-. Hence, FPGA devices offer an exceptional solution to efficiently implement advanced PHY-layer techniques, as it will be detailed throughout this thesis. Chapter 2: The PHY-layer development ecosyste...

Citation Context

...panish) of Universidade da Coruña are quite diverse. The common denominator of their results is the experimentalnature of the presented work. The group has also developed a flexible FPGAbased testbed =-=[32]-=-. During the review, we will identify this platform under the name of GTEC-testbed. A key feature of the testbed is its distributed multilayer software architecture, designed to facilitate the access ...

Citation Context

... in the off-line-based rapid prototyping methodology is found in the Vienna MIMO testbed. The latter was used to evaluate a CFO compensation scheme for Single Input Single Output (SISO) WiMAX systems =-=[58]-=- and the performance assessment of MIMO High-Speed DownLink (DL) Packet Access (HSDPA) [59]. An extension of this testbed [60] was the fruit of the collaboration between the Austrian and the GTEC grou...

Citation Context

...oncept of advanced real-world experimental setups. Some indicative developments that were built upon this testbed include the full frequency reuse (and extended coverage) by employing indoor relaying =-=[89]-=-, interference management through CoMP joint transmission [90] and interference-aware scheduling in the DL [91]. Finally, the last identified HW/SW co-design approach is centred around the design and ...

Citation Context

... one presented in [105]. Moreover, the broad experience of ETH in the field of VLSI design is widely documented in the literature. Some indicative examples include the design of a MIMO sphere decoder =-=[120]-=-, a CompressedSensing (CS)-based channel estimation for LTE receivers [121] and a Successive Interference Cancellation (SIC)-based MIMO detector [122]. A couple of additional notable VLSI implementati...

Citation Context

...IP cores, embedded microprocessors and other dedicated processing components can be used in FPGA devices, to serve the needs of particular applications that require this type of arithmetic operations =-=[12, 13]-=-. To conclude, it is worth mentioning that the MATLAB DSP System Toolbox TM [DST] provides algorithms and tools to help automating the design of advanced PHY-layer techniques for both implementation c...

Citation Context

... design details are contemplated from the high-level description, then both the developmentcycle time and the design complexity of HLS-based flows are comparable to that of custom HDL code generation =-=[26]-=-. The previous RTL design and implementation approach changes a bit when considering the automated code generation from a Simulink model. Although it is true that it usually requires to restrict the d...

Citation Context

...tems [Burg et al., 2006], a topic that still remains challenging nowadays. Although a MU MIMO testbed relying on the FPGA technology was developed and utilized for the prototyping of advanced systems =-=[33]-=-, the proposed designs were optimized at gate-level in a true VLSI implementation approach [Studer et al., 2010]. Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut (HHI) (Berlin, Ge...

Citation Context

...e Division Duplex (TDD) zero-forcing linear precoding for OFDM-based systems [49], standardcompliant MIMO-OFDMA mobile WiMAX receivers [50, 51] or Coordinated Multi-Point (CoMP) for LTE-based systems =-=[52]-=-. A popular initiative towards this end is provided by the openly accessible WarpLab framework [53]. WarpLab provides the necessary software that faChapter 3: Related work and contribution 43 cilitate...

Citation Context

...he latter was used to evaluate a CFO compensation scheme for Single Input Single Output (SISO) WiMAX systems [58] and the performance assessment of MIMO High-Speed DownLink (DL) Packet Access (HSDPA) =-=[59]-=-. An extension of this testbed [60] was the fruit of the collaboration between the Austrian and the GTEC groups. Another relevant example of this collaboration is the experimental validation of an Ada...

Citation Context

...mplete PHY-layer of modern wireless communication systems, hybrid solutions based on the previously discussed off-line prototyping methodology have been proposed. A representative example is found in =-=[68]-=- where a real-time implementation of the synchronization stage of a 2x2 MIMOOFDM receiver is combined with an off-line baseband HLPL-model. A complementary effort is found in [69] where a MATLAB chann...

Citation Context

...tive developments that were built upon this testbed include the full frequency reuse (and extended coverage) by employing indoor relaying [89], interference management through CoMP joint transmission =-=[90]-=- and interference-aware scheduling in the DL [91]. Finally, the last identified HW/SW co-design approach is centred around the design and implementation of an embedded FPGA-based processor, which coul...

Citation Context

...r allocation in [109]. Several authors have as a goal to efficiently implement the most advanced DSP techniques through optimized custom HDL code. Some indicative examples are iterative MIMO decoding =-=[110]-=-, STBC MIMO decoding [111], autocorrelation-based OFDM signal detection for CR systems [112], reconfigurable twodimensional pipeline FFT processor for MIMO OFDM systems [113], fixed sphere decoder [11...

Citation Context

...rallel Low-Density Parity Check (LDPC) decoder presented in [116], a lowpower synchronization technique for WiMAX systems described in [117] and a high-throughput iterative MIMO detection detailed in =-=[118]-=-. Relation to the work presented in this thesis: the presented references, summarized in in Table 3.8, are using custom HDL code to prototype various advanced PHY-layer techniques. In the same way, a ...

Citation Context

... of VLSI design is widely documented in the literature. Some indicative examples include the design of a MIMO sphere decoder [120], a CompressedSensing (CS)-based channel estimation for LTE receivers =-=[121]-=- and a Successive Interference Cancellation (SIC)-based MIMO detector [122]. A couple of additional notable VLSI implementation of WLAN transceivers are reported in [123,124]. Similarly, in [125] the ...

Citation Context

...mples include the design of a MIMO sphere decoder [120], a CompressedSensing (CS)-based channel estimation for LTE receivers [121] and a Successive Interference Cancellation (SIC)-based MIMO detector =-=[122]-=-. A couple of additional notable VLSI implementation of WLAN transceivers are reported in [123,124]. Similarly, in [125] the ASIC implementation of a highthroughput channel estimator for LTE receivers...

Citation Context

... estimation for LTE receivers [121] and a Successive Interference Cancellation (SIC)-based MIMO detector [122]. A couple of additional notable VLSI implementation of WLAN transceivers are reported in =-=[123,124]-=-. Similarly, in [125] the ASIC implementation of a highthroughput channel estimator for LTE receivers is presented by the research team in Vienna. Furthermore, many authors have worked towards efficie...

Citation Context

...IP cores, embedded microprocessors and other dedicated processing components can be used in FPGA devices, to serve the needs of particular applications that require this type of arithmetic operations =-=[12, 13]-=-. To conclude, it is worth mentioning that the MATLAB DSP System Toolbox TM [DST] provides algorithms and tools to help automating the design of advanced PHY-layer techniques for both implementation c...

Citation Context

...35 48 71 Precision (Mantissa Size) G Fl op s Performance comparison FPGA (Xilinx XC6VSX475T) GPU (NVIDIA GTX480) (b) GPU vs. FPGA performance comparison when implementing a dense linear system solver =-=[20]-=-. (c) Energy consumed by GPP, GPU and FPGA devices in a sliding-window application [21]. Figure 2.6: Recent implementation technology comparison studies. ergy consumption). FPGAs constitute the ideal ...

Citation Context

...e restrictions that apply: only very limited language constructs and specific functions or routines can be automatically translated into an HDL description, and often not with a very efficient result =-=[23, 24]-=-. Additionally, the automated HDL code generation suffers in the translation of the floating-point arithmetic to a limited dynamic range. In other words, it is frequent the requirement to predetermine...

Citation Context

...HW/SW development platform in the area of digital radio communications. The OpenAirInterface is aimed to be utilized both for real-time DSP Chapter 3: Related work and contribution 41 implementations =-=[40]-=- and as a large scale wireless emulation platform [41]. 3.2 Review of related work As already mentioned the classification of the literature review is is structured around the ecosystem presented by F...

Citation Context

...ool in the research community, that will allow researchers to fairly compare their algorithms. Some indicative use cases of this simulation framework are interference management in a MU MIMO scenario =-=[43]-=-, optimal power distribution among pilot and data subcarriers [44] and Signal-to-Interference-Plus-Noise Ratio (SINR) prediction in a multi-cell scenario [45]. Similarly, an extension to the widely us...

Citation Context

...ssess the performance of a wide variety of PHY-layer schemes: Time Division Duplex (TDD) zero-forcing linear precoding for OFDM-based systems [49], standardcompliant MIMO-OFDMA mobile WiMAX receivers =-=[50, 51]-=- or Coordinated Multi-Point (CoMP) for LTE-based systems [52]. A popular initiative towards this end is provided by the openly accessible WarpLab framework [53]. WarpLab provides the necessary softwar...

Citation Context

... the WARP boards. Indicative prototyping results are the full-duplex scheme [54] and MU Beamforming (MUBF) [55] for WLAN systems. Similarly, off-line prototyping efforts are also reported by both HHI =-=[56]-=-1, related to interference management in a frequency reuse scheme, and ETH [57], regarding the compensation of residual transmit signal impairments. A major reference in the off-line-based rapid proto...

Citation Context

...ration between the Austrian and the GTEC groups. Another relevant example of this collaboration is the experimental validation of an Adaptive Modulation and Coding (AMC) scheme for MIMO WiMAX systems =-=[61]-=-. The GTEC-testbed also provides an interesting off-line prototyping platform. For instance, in [62] the performance of a Bit Interleaved Coded Modulation (BICM) scheme is evaluated under realistic ch...

Citation Context

... example is found in [68] where a real-time implementation of the synchronization stage of a 2x2 MIMOOFDM receiver is combined with an off-line baseband HLPL-model. A complementary effort is found in =-=[69]-=- where a MATLAB channel model is used to test an FPGA-based OFDM transceiver. Furthermore, a HIL deployment is used by the GTEC group where a real-time FPGA-based channel emulator is utilized to reali...

Citation Context

.... Furthermore, a HIL deployment is used by the GTEC group where a real-time FPGA-based channel emulator is utilized to realistically assess the performance of a MATLAB-modelled mobile WiMAX PHY-layer =-=[70]-=-. Relation to the work presented in this thesis: the hardware-accelerated simulations, summarized in Table 3.3, represent preliminary efforts towards the real-time implementation of advanced PHY-layer...

Citation Context

...le 3.3: Synopsis of the encountered hardware-accelerated PHY-layer simulations. software-based PHY-layer serves better the requirements of Software Defined Radio (SDR)-based systems. Indicatively, in =-=[71]-=- a GPP is used to implement a spectrum-sensing controller of a frequency agile Wireless Sensor Network (WSN). An ideal vehicle to deploy GPP-based SDR systems is provided by the OpenAirInterface wirel...

Citation Context

...exibility of the previous setup allows the rapid realization of a plethora of SDR-oriented scenarios. Two indicative examples are: a single-frequency mesh network based on a distributed MIMO receiver =-=[72]-=- and an opportunistic cognitive transmission scheme for OFDM-based broadband systems [73]. The general-purpose design of the utilized processors is the principal performance-limiting factor of softwar...

Citation Context

...rly, a cell-based platform developed at HHI is utilized to conduct a preliminary capacity-analysis towards a 12x12 MIMO-OFDM LTE+ receiver [75] and to implement a MIMO turbo receiver for LTE-Advanced =-=[76]-=-. The GPUs provide another processing solution that features intensive parallel computation capacity. This has been the target technology that was selected to implement advanced MIMO detectors by both...

Citation Context

...d loss of RTL implementation efficiency due to the non-optimal functionality of the HLS tools, does not constitute a serious issue for preliminary development analyses. A relevant example is given in =-=[80]-=- where a spectrum sensing technique for OFDM-based SDR transceivers is evaluated. Similarly, a hybrid Simulink-based design, combining both automatic Matlabto-HDL and pre-verified System Generator blo...

Citation Context

...LS capabilities of the EDA tool automatically translate this model to HDL code. Two indicative use cases of the WARP platform implement a cooperative OFDM-based PHY-layer [95] and a MIMO LTE receiver =-=[96]-=-. It should be noted that few design details are usually provided in the encountered references, where the focus is generally laid on the experimental verification of advanced PHY-layer schemes. Never...

Citation Context

...igurable sphere detector for MU-MIMO SDR systems [100], a soft-output detection with turbo decoding [101], a robust channel estimator [102], MIMO-OFDM based channel coding and interleaving techniques =-=[103]-=- and a dynamic spectrum allocation algorithm for OFDMA systems [104]. Relation to the work presented in this thesis: the encountered schematic entry HDL-based designs, summarized in Table 3.7, are def...

Citation Context

...eral authors have as a goal to efficiently implement the most advanced DSP techniques through optimized custom HDL code. Some indicative examples are iterative MIMO decoding [110], STBC MIMO decoding =-=[111]-=-, autocorrelation-based OFDM signal detection for CR systems [112], reconfigurable twodimensional pipeline FFT processor for MIMO OFDM systems [113], fixed sphere decoder [114] and 2-phase channel est...

Citation Context

...nced DSP techniques through optimized custom HDL code. Some indicative examples are iterative MIMO decoding [110], STBC MIMO decoding [111], autocorrelation-based OFDM signal detection for CR systems =-=[112]-=-, reconfigurable twodimensional pipeline FFT processor for MIMO OFDM systems [113], fixed sphere decoder [114] and 2-phase channel estimation for mobile WiMAX receivers [115]. An important point that ...

Citation Context

... most adequate technology for the digital realization of novel PHY-layer techniques. Mapping the PHY-layer Chapter 1: Introduction 6 Figure 1.5: Recent trend of programmable and parallel technologies =-=[5]-=-. of different systems to this enormous design-space results in a widely varying performance and energy consumption, not solely when examining the target implementation technology, but also the differ...

Citation Context

...mory capacity. This gives them unprecedented parallel computing capacity from one side and flexibility from the other side (see Figure 1.6), when utilizing run-time partial reconfiguration techniques =-=[6]-=-, or when using the on-chip hard-wired multi-core microprocessors [7], available in certain families, following by this way a hardware/software (HW/SW) co-design approach. Therefore, FPGAbased impleme...

Citation Context

...ity from one side and flexibility from the other side (see Figure 1.6), when utilizing run-time partial reconfiguration techniques [6], or when using the on-chip hard-wired multi-core microprocessors =-=[7]-=-, available in certain families, following by this way a hardware/software (HW/SW) co-design approach. Therefore, FPGAbased implementations are ideal to meet the needs posed by the development of real...

Citation Context

... conditions. FPGAs are processing devices renown for their capacity to host custom Chapter 1: Introduction 7 Figure 1.6: Performance vs. flexibility of different PHY-layer implementation technologies =-=[8]-=-. parallel digital processing systems and, thus, able to implement complex DSPintensive algorithms and advanced wireless communication systems. Modern FPGA devices have gone even further by integratin...

Citation Context

...s) able to integrate processing elements of different coding and system design domains (i.e., HLPL or HDL), in order to target different processing component categories (e.g., GPP, DSP, FPGA or ASIC) =-=[14]-=-. Hence, the main challenge of HW/SW co-design is to decide in an optimal way which part of the system is implemented in software and which part in hardware, accounting for the characteristics of the ...

Citation Context

... HW/SW co-design solution. Modern FPGA devices offer the flexible (and relatively low-cost) means for the realization of efficient dedicated hardware designs requiring of massive parallel computation =-=[15, 16]-=-. Moreover, many recent studies have shown that (when properly utilized) they are capable of outperforming the advanced non-HDL implementation technologies by providing higher performance and/or energ...

Citation Context

...testbed in this review. The latter is simultaneously enabling both an off-line approach and the real-time implementation of advanced DSP-based systems considering realistically conditioned RF signals =-=[29]-=-. Department of Electrical and Computer Engineering, Rice University (Houston, Texas, United States of America) Rice University is the birthplace of the popular Wireless Open-Access Research Platform ...

Citation Context

...o communications. The OpenAirInterface is aimed to be utilized both for real-time DSP Chapter 3: Related work and contribution 41 implementations [40] and as a large scale wireless emulation platform =-=[41]-=-. 3.2 Review of related work As already mentioned the classification of the literature review is is structured around the ecosystem presented by Figure 2.1. It is important to note, that due to the fo...

Citation Context

...ety of cases where novel PHY-layer solutions are required. For instance, the power minimization achieved by jointly configuring relevant PHY-layer and hardware parameters is realistically analysed in =-=[42]-=-. Hence, the provision of realistic simulation models has been a long-term objective of many authors within the academic community. Moreover, another vertical relationship is encountered in the reutil...

Citation Context

...rference management in a MU MIMO scenario [43], optimal power distribution among pilot and data subcarriers [44] and Signal-to-Interference-Plus-Noise Ratio (SINR) prediction in a multi-cell scenario =-=[45]-=-. Similarly, an extension to the widely used NS-2 network simulator in order to include a cooperative OFDM PHY-layer is proposed and verified based on a real-time implementation over the WARP testbed ...

Citation Context

...imilarly, an extension to the widely used NS-2 network simulator in order to include a cooperative OFDM PHY-layer is proposed and verified based on a real-time implementation over the WARP testbed in =-=[46]-=-. Furthermore, in [47] the large scale wireless emulation platform provided by the OpenAirInterface is used to simulate a MU LTE-based frequency reuse scenario. In another case, a channel model derive...

Citation Context

...t MIMO-OFDMA mobile WiMAX receivers [50, 51] or Coordinated Multi-Point (CoMP) for LTE-based systems [52]. A popular initiative towards this end is provided by the openly accessible WarpLab framework =-=[53]-=-. WarpLab provides the necessary software that faChapter 3: Related work and contribution 43 cilitates the direct interaction with the WARP hardware from the MATLAB workspace. This typically includes ...

Citation Context

...O compensation scheme for Single Input Single Output (SISO) WiMAX systems [58] and the performance assessment of MIMO High-Speed DownLink (DL) Packet Access (HSDPA) [59]. An extension of this testbed =-=[60]-=- was the fruit of the collaboration between the Austrian and the GTEC groups. Another relevant example of this collaboration is the experimental validation of an Adaptive Modulation and Coding (AMC) s...

Citation Context

...he experimental validation of an Adaptive Modulation and Coding (AMC) scheme for MIMO WiMAX systems [61]. The GTEC-testbed also provides an interesting off-line prototyping platform. For instance, in =-=[62]-=- the performance of a Bit Interleaved Coded Modulation (BICM) scheme is evaluated under realistic channel conditions. Similarly, the GTAS-testbed is utilized in [63] for the experimental characterizat...

Citation Context

... a very powerful off-line prototyping platform is resulting from the connection of both testbeds. Two illustrative use cases are the evaluation of advanced channel estimation schemes for MIMO systems =-=[64]-=- and the validation of interference-alignment techniques for MU MIMO systems [65]. Finally, a measurement-based infrastructure recently deployed by TU Wien aims at assessing the real-world performance...

Citation Context

...rence-alignment techniques for MU MIMO systems [65]. Finally, a measurement-based infrastructure recently deployed by TU Wien aims at assessing the real-world performance of the IEEE 802.11p standard =-=[66]-=-. Relation to the work presented in this thesis: the encountered off-line prototyping research, summarized in Table 3.2, is providing signals with close-toreal-world conditions (i.e., accounting for b...

Citation Context

...tic behaviour of the analog hardware and the lack of control over the noise and the real-world wireless channel realization, makes it impossible to fully reproduce or trigger specific test conditions =-=[67]-=-. As it can be deduced from the previous, a carefully designed real-time PHYlayer implementation is required to realistically evaluate adaptive DSP techniques. Notwithstanding, given the elevated cost...

Citation Context

...d scenarios. Two indicative examples are: a single-frequency mesh network based on a distributed MIMO receiver [72] and an opportunistic cognitive transmission scheme for OFDM-based broadband systems =-=[73]-=-. The general-purpose design of the utilized processors is the principal performance-limiting factor of software-based PHY-layer implementations. Nonetheless, the inclusion of parallel computing archi...

Citation Context

...echnology that was selected to implement advanced MIMO detectors by both the Vienna and the Rice University groups. More specifically, a preliminary implementation of a sphere decoder is described in =-=[77]-=- and a GPU-based reconfigurable soft-output detector is detailed in [78]. Relation to the work presented in this thesis: the encountered nonChapter 3: Related work and contribution 47 HDL initiatives,...

Citation Context

...ovides an excellent vehicle for rapid prototyping. This is due to the fact that the tedious RTL design is abstracted away at the cost of losing implementation efficiency. Indicatively, the authors in =-=[79]-=-, use both HLS tools and a custom RTL design flow to implement a WiMAX transmitter. The previously mentioned loss of RTL implementation efficiency due to the non-optimal functionality of the HLS tools...

Citation Context

... an efficient PHY/MAC cross-layer design are reported in [84], enabling the design and implementation of a distributed cooperative MAC and OFDM-based PHY layer. A similar architecture is presented in =-=[85]-=- by the GTEC-group, where it is described the development of a 4x4 MIMO-enhanced transceiver based on the IEEE 802.11a standard, featuring a custom FPGA-implemented baseband processor tightly integrat...

Citation Context

...able mobile WiMAX PHY-layer implementation is presented by the GTEC-group, where an FPGA is in charge of the most intensive DSP blocks and a DSP processor implements the subchannel-related operations =-=[87]-=-. In most of the cases, the advanced wireless communication systems implemented by the HHI-group are based on a well defined HW/SW co-design strategy, which takes advantage of the virtues of both FPGA...

Citation Context

...-time re-programmability to support all the functional requirements of any OFDM-based air-interface; at the same time it achieves the reuse of the baseband processing resources for multiple standards =-=[92]-=-. The capabilities of this custom baseband processor are investigated in [93] by analysing its capacity to implement a 802.11p receiver. Similar work is presented in [94], where a custom FPGA-based as...

Citation Context

...ources for multiple standards [92]. The capabilities of this custom baseband processor are investigated in [93] by analysing its capacity to implement a 802.11p receiver. Similar work is presented in =-=[94]-=-, where a custom FPGA-based assemblyprogrammable processing architecture for baseband DSP functionality is implemented and utilized to prototype a quasi-optimal sphere decoder. Additional references h...

Citation Context

...nvironment, which is connected with the Xilinx EDA tool-chain through the System Generator, are able to accommodate a large number of similar system developments. A representative example is found in =-=[97]-=-, where the authors implement a MIMO WLAN PHY-layer design favouring resource-reuse, and another in [98], where the GTAS-testbed is used to develop and validate a PHY-layer prototype that combines ope...

Citation Context

... ve H W /S W co -d es ig n in it ia ti ve s fo un d in th e lit er at ur e. Chapter 3: Related work and contribution 54 Other related examples include a fixed-complexity high-throughput MIMO detector =-=[99]-=-, a configurable sphere detector for MU-MIMO SDR systems [100], a soft-output detection with turbo decoding [101], a robust channel estimator [102], MIMO-OFDM based channel coding and interleaving tec...

Citation Context

...tion 54 Other related examples include a fixed-complexity high-throughput MIMO detector [99], a configurable sphere detector for MU-MIMO SDR systems [100], a soft-output detection with turbo decoding =-=[101]-=-, a robust channel estimator [102], MIMO-OFDM based channel coding and interleaving techniques [103] and a dynamic spectrum allocation algorithm for OFDMA systems [104]. Relation to the work presented...

Citation Context

...lude a fixed-complexity high-throughput MIMO detector [99], a configurable sphere detector for MU-MIMO SDR systems [100], a soft-output detection with turbo decoding [101], a robust channel estimator =-=[102]-=-, MIMO-OFDM based channel coding and interleaving techniques [103] and a dynamic spectrum allocation algorithm for OFDMA systems [104]. Relation to the work presented in this thesis: the encountered s...

Citation Context

...t detection with turbo decoding [101], a robust channel estimator [102], MIMO-OFDM based channel coding and interleaving techniques [103] and a dynamic spectrum allocation algorithm for OFDMA systems =-=[104]-=-. Relation to the work presented in this thesis: the encountered schematic entry HDL-based designs, summarized in Table 3.7, are defining custom RTL architectures, often relying on pre-verified IP cor...

Citation Context

...pace-Time Block Code (STBC)-based MIMO scheme, whereas in [107] a Transmit Antenna Selection (TAS) configuration is developed. A DSP-block re-utilization for a minimized hardware cost is presented in =-=[108]-=- and a spectrum-aware adaptive subcarrier allocation in [109]. Several authors have as a goal to efficiently implement the most advanced DSP techniques through optimized custom HDL code. Some indicati...

Citation Context

...7] a Transmit Antenna Selection (TAS) configuration is developed. A DSP-block re-utilization for a minimized hardware cost is presented in [108] and a spectrum-aware adaptive subcarrier allocation in =-=[109]-=-. Several authors have as a goal to efficiently implement the most advanced DSP techniques through optimized custom HDL code. Some indicative examples are iterative MIMO decoding [110], STBC MIMO deco...

Citation Context

... detection for CR systems [112], reconfigurable twodimensional pipeline FFT processor for MIMO OFDM systems [113], fixed sphere decoder [114] and 2-phase channel estimation for mobile WiMAX receivers =-=[115]-=-. An important point that has to be underlined is that the extremely demanding bit-intensive computation of the DSP algorithms proposed to implement the PHY-layer of future wireless communication syst...

Citation Context

...mplementation. Indicative related work in this sense is a fullyparallel Low-Density Parity Check (LDPC) decoder presented in [116], a lowpower synchronization technique for WiMAX systems described in =-=[117]-=- and a high-throughput iterative MIMO detection detailed in [118]. Relation to the work presented in this thesis: the presented references, summarized in in Table 3.8, are using custom HDL code to pro...

Citation Context

...vers [121] and a Successive Interference Cancellation (SIC)-based MIMO detector [122]. A couple of additional notable VLSI implementation of WLAN transceivers are reported in [123,124]. Similarly, in =-=[125]-=- the ASIC implementation of a highthroughput channel estimator for LTE receivers is presented by the research team in Vienna. Furthermore, many authors have worked towards efficient implementations of...