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- Ma, Wing-Kin, et al.
(författare)
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Some results on 16-QAM MIMO detection using semidefinite relaxation
- 2008
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Ingår i: 2008 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING. - 9781424414833 ; , s. 2673-2676
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Konferensbidrag (refereegranskat)abstract
- Semidefinite relaxation (SDR) is a high-performance efficient approach to MIMO detection especially for the BPSK or QPSK constellations. Recently, a number of research endeavors have focused on extending SDR to the case of 16-QAM constellations. This paper reports two interesting and useful results on this problem. First, we show that two of the existing 16-QAM SDR receivers, namely the polynomial-inspired SDR (PI-SDR) and bound-constrained SDR (BC-SDR) methods, are equivalent. Second, we develop a specialized interior-point algorithm for the implementation of BC-SDR. The proposed algorithm is computationally efficient exploiting the BC-SDR structures, and enables us to handle larger problem sizes in practice.
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| 2. |
- Ma, Wing-Kin, et al.
(författare)
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The Equivalence of Semidefinite Relaxation MIMO Detectors for Higher-Order QAM
- 2009
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Ingår i: IEEE Journal on Selected Topics in Signal Processing. - 1932-4553. ; 3:6, s. 1038-1052
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Tidskriftsartikel (refereegranskat)abstract
- In multi-input multi-output (MIMO) detection, semidefinite relaxation (SDR) has been shown to be an efficient high-performance approach. For BPSK and QPSK, it has been found that SDR can provide near-optimal bit error probability performance. This has stimulated a number of recent research endeavors that aim to apply SDR to the high-order QAM cases. These independently developed SDRs are different in concept, structure and complexity, and presently no serious analysis has been given to compare these methods. This paper analyzes the relationship of three such SDR methods, namely the polynomial-inspired SDR (PI-SDR) by Wiesel et al., the bound-constrained SDR (BC-SDR) by Sidiropoulos and Luo, and the virtually-antipodal SDR (VA-SDR) by Mao et al. Rather unexpectedly, we prove that the three SDRs are equivalent in the following sense: The three SDRs yield the same optimal objective values, and their optimal solutions have strong correspondences. Specifically, we establish this solution equivalence between BC-SDR and VA-SDR for any 4(q)-QAM constellations, and that between BC-SDR and PI-SDR for 16-QAM and 64-QAM. Moreover, the equivalence result holds for any channel, problem size, and signal-to-noise ratio. Our theoretical findings are confirmed by simulations, where the three SDRs offer identical symbol error probabilities. Additional simulation results are also provided to demonstrate the effectiveness of SDR compared to some other MIMO detectors, in terms of complexity and symbol error performance.
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| 3. |
- Zhang, Wen-Chao, et al.
(författare)
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Clinical and pathological analysis of malignant carotid body tumour : a report of nine cases
- 2009
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 129:11, s. 1320-1325
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions. Malignant carotid body tumour (MCBT) is a clinically rare disease that often invades the carotid artery and cranial nerves. Diagnosis of malignant tumour should be based on extensive invasion of neighbouring organs and distant metastasis. Extensive resection should be undertaken early. Radiotherapy is effective, whereas chemotherapy is uncertain. Objective. To summarize the clinical pathological and prognostic characteristics of MCBT and explore methods for diagnosis and treatment. Materials and methods. The study material comprised clinical, pathological, therapeutic and follow-up data concerning nine patients (four males, five females) with MCBT, treated at Tianjin Cancer Hospital between January 1956 and June 2006. The material was analysed retrospectively. Disease duration averaged 6.4 years. Shamblin classification was: one case, type ?; 8 cases, type ?. All nine patients underwent ultrasound examination, four underwent digital subtraction arteriography (DSA) and three had magnetic resonance angiography (MRA). Five patients underwent preoperative training of compression of the carotid (Matas test). Extensive resection was performed in all nine cases. Results. The carotid artery was blocked in three patients. In one of these the artery was reconstructed with a vascular prosthesis, while two underwent carotid ligation. Eight patients suffered from a cranial nerve dysfunction (defect) and two suffered postoperatively from a hoarse voice, four had a glossal deviation, five had Horner's syndrome and one had a deviation of the lip angle. One patient had a congestive cough. The histopathological diagnosis in all nine cases was MCBT. One patient had metastases to a cervical lymph node and lung and another had liver metastasis. The median follow-up period was 3 years (range 6 months to 14 years). Six patients survived surgery, of whom two underwent radiotherapy. Two patients died and one could not be traced.
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