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- Asghar, Rizwan
(författare)
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Flexible Interleaving Sub–systems for FEC in Baseband Processors
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Interleaving is always used in combination with an error control coding. It spreads the burst noise, and changes the burst noise to white noise so that the noise induced bit errors can be corrected. With the advancement of communication systems and substantial increase in bandwidth requirements, use of coding for forward error correction (FEC) has become an integral part in the modern communication systems. Dividing the FEC sub-systems in two categories i.e. channel coding/de-coding and interleaving/de-interleaving, the later appears to be more varying in permutation functions, block sizes and throughput requirements. The interleaving/de-interleaving consumes more silicon due to the silicon cost of the permutation tables used in conventional LUT based approaches. For multi-standard support devices the silicon cost of the permutation tables can grow much higher resulting in an un-efficient solution. Therefore, the hardware re-use among different interleaver modules to support multimode processing platform is of significance.The broadness of the interleaving algorithms gives rise to many challenges when considering a true multimode interleaver implementation. The main challenges include real-time low latency computation for different permutation functions, managing wide range of interleaving block sizes, higher throughput, low cost, fast and dynamic reconfiguration for different standards, and introducing parallelism where ever necessary.It is difficult to merge all currently used interleavers to a singlearchitecture because of different algorithms and throughputs; however, thefact that multimode coverage does not require multiple interleavers to workat the same time, provides opportunities to use hardware multiplexing. The multimode functionality is then achieved by fast switching between differentstandards. We used the algorithmic level transformations such as 2-Dtransformation, and realization of recursive computations, which appear to bethe key to bring different interleaving functions to the same level. In general,the work focuses on function level hardware re-use, but it also utilizesclassical data-path level optimizations for efficient hardware multiplexingamong different standards.The research has resulted in multiple flexible architectures supporting multiple standards. These architectures target both channel interleaving and turbo-code interleaving. The presented architectures can support both types of communication systems i.e. single-stream and multi-stream systems. Introducing the algorithmic level transformations and then applying hardware re-use methodology has resulted in lower silicon cost while supporting sufficient throughput. According to the database searching in March 2010, we have the first multimode interleaver core covering WLAN (802.11a/b/g and 802.11n), WiMAX (802.16e), 3GPP-WCDMA, 3GPP-LTE, and DVB-T/H on a single architecture with minimum silicon cost. The research also provides the support for parallel interleaver address generation using different architectures. It provides the algorithmic modifications and architectures to generate up to 8 addresses in parallel and handle the memory conflicts on-the-fly.One of the vital requirements for multimode operation is the fast switching between different standards, which is supported by the presented architectures with minimal cycle cost overheads. Fast switching between different standards gives luxury to the baseband processor to re-configure theinterleaver architecture on-the-fly and re-use the same hardware for another standard. Lower silicon cost, maximum flexibility and fast switchability among multiple standards during run time make the proposed research a good choice for the radio baseband processing platforms.
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| 2. |
- Helldin, L., et al.
(författare)
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A functional comparison of patients with schizophrenia between the North and South of Europe
- 2012
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Ingår i: European psychiatry. - : Cambridge University Press (CUP). - 0924-9338 .- 1778-3585. ; 27:6, s. 442-444
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The main objective of this study was to compare clinical and functional outcomes of patients with schizophrenia in Italy and Sweden with a special focus on daily functioning performance and real life milestones. Also, to study if outcome is to be regarded as a consequence of premorbid function, the level of symptom control and functional capacity or if other influences, such as cultural differences, must parallel be considered. Method: Ninety-five patients from three centres, Milan and Naples in Italy and Trollhattan in Sweden were investigated. The Positive and Negative Syndrome Scale and the UCSD Performance-Based Skills Assessment - Brief version were used together with patients' school history and their status of accommodation and occupation. Results: Patients in Trollhattan were more likely to live independently and patients in Naples to have a work or take part in education. Differences in symptoms and the performance test were present but subtle. Discussion: Differences in real life milestones were not explained by corresponding differences in symptoms, premorbid function or the performance-based test. It is therefore not appropriate only to present functional outcome as an expression of how successful treatment has been. (C) 2011 Elsevier Masson SAS. All rights reserved.
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