| 1. |
- Du, Jinfeng, et al.
(författare)
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Capacity Bounds for Backhaul-Supported Wireless Multicast Relay Networks with Cross-Links
- 2011
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Ingår i: IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), 2011. - NEW YORK : IEEE conference proceedings. - 9781612842325 - 9781612842318 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- We investigate the capacity bounds for a wireless multicast relay network where two sources simultaneously multicast to two destinations through Gaussian channels with the help of a full-duplex relay node. All the individual channel gains are assumed to be time-invariant and known to every nodes in the network. The transmissions from two sources and from the relay use the same channel resource (i.e. co-channel transmission) and the two source nodes are connected with an orthogonal error-free backhaul. This multicast relay network is generic in the sense that it can be extended to more general networks by tuning the channel gains within the range [0, ∞). By extending the proof of the converse developed by Cover and El Gamal for the Gaussian relay channel, we characterize the cut-set bound for this multicast relay network. We also present a lower bound by using decoding-and-forward relaying combined with network beam-forming.
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| 2. |
- Du, Jinfeng, et al.
(författare)
-
Capacity bounds for relay-aided wireless multiple multicast with backhaul
- 2010
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Ingår i: 2010 International Conference on Wireless Communications and Signal Processing, WCSP 2010. - NEW YORK : IEEE conference proceedings. - 9781424475568 - 9781424475544 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- We investigate the capacity bounds for relay-aided two-source two-destination wireless networks with backhaul support between source nodes. Each source multicasts its own message to all destinations with the help of an intermediate relay node, which is full-duplex and shared by both sources. We are aiming to characterize the capacity region of this model given discrete memoryless Gaussian channels. We establish three capacity upper bounds by relaxing the cut-set bound, and by extending two capacity bounds originally derived for MIMO relay channels. We also present one lower bound by using decoding-and-forward relaying combined with network beam-forming.
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| 3. |
- Du, Jinfeng, et al.
(författare)
-
Cooperative Network Coding Strategies for Wireless Relay Networks with Backhaul
- 2011
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Ingår i: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 59:9, s. 2502-2514
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Tidskriftsartikel (refereegranskat)abstract
- We investigate cooperative network coding strategies for relay-aided two-source two-destination wireless networks with a backhaul connection between the source nodes. Each source multicasts information to all destinations using a shared relay. We study cooperative strategies based on different network coding schemes, namely, finite field and linear network coding, and lattice coding. To further exploit the backhaul connection, we also propose network coding based beamforming. We measure the performance in term of achievable rates over Gaussian channels, and observe significant gains over benchmark schemes. We derive the achievable rate regions for these schemes and find the cut-set bound for our system. We also show that the cut-set bound can be achieved by network coding based beamforming when the signal-to-noise ratios lie in the sphere defined by the source-relay and relay-destination channel gains.
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| 4. |
- Du, Jinfeng, et al.
(författare)
-
Cooperative strategies for relay-aided multi-cell wireless networks with backhaul
- 2010
-
Ingår i: 2010 IEEE Information Theory Workshop, ITW 2010 - Proceedings. - NEW YORK : IEEE conference proceedings. - 9781424482627 - 9781424482634 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- We investigate cooperative strategies for relay-aided multi-source multi-destination wireless networks with backhaul support. Each source multicasts information to all destinations using a shared relay. We study cooperative strategies based on different network coding (NC) schemes, namely, finite field NC (FNC), linear NC (LNC), and lattice coding. To further exploit the backhaul connection, we also propose NC-based beam-forming (NBF). We measure the performance in term of achievable rates over Gaussian channels and observe significant gains over a benchmark scheme. The benefit of using backhaul is also clearly demonstrated in most of scenarios.
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| 5. |
- Du, Jinfeng
(författare)
-
Cooperative Strategies in Multi-Terminal Wireless Relay Networks
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Smart phones and tablet computers have greatly boosted the demand for services via wireless access points, keeping constant pressure on the network providers to deliver vast amounts of data over the wireless infrastructure. To enlarge coverage and enhance throughput, relaying has been adopted in the new generation of wireless communication systems, such as in the Long-Term Evolution Advanced standard, and will continue to play an important role in the next generation wireless infrastructure. Depending on functionality, relaying can be characterizing into three main categories: amplify-and-forward (AF), compression-and-forward (CF), and decode-and-forward (DF). In this thesis, we investigate different cooperative strategies in wireless networks when relaying is in use.We first investigate the capacity outer and inner bounds for a wireless multicast relay network where two sources, connected by error-free backhaul, multicast to two destinations with the help of a full-duplex relay node. For high-rate backhaul scenarios, we find the exact cut-set bound of the capacity region by extending the proof of the converse for the Gaussian relay channel. For low-rate backhaul scenarios, we present two genie-aided outer bounds by extending the previous proof and introducing two lemmas on conditional (co-)variance. Our inner bounds are derived from various cooperative strategies by combining DF/CF/AF relaying with network coding schemes. We also extend the noisy network coding scheme and the short-message noisy network coding approach to correlated sources. For low-rate backhaul, we propose a new coding scheme, partial-decode-and-forward based linear network coding. We derive the achievable rate regions for these schemes and measure the performance in term of achievable rates over Gaussian channels. By numerical investigation we observe significant gains over benchmark schemes and demonstrate that the gap between upper and lower bounds is in general not large. We also show that for high-rate backhaul, the cut-set bound can be achieved when the signal-to-noise ratios lie in the sphere defined by the source-relay and relay-destination channel gains.For wireless networks with independent noise, we propose a simple framework to get capacity outer and inner bounds based on the ``one-shot'' bounding models. We first extend the models for two-user broadcast channels to many-user scenarios and then establish the gap between upper and lower bounding models. For networks with coupled links, we propose a channel decoupling method which can decompose the network into overlapping multiple-access channels and broadcast channels. We then apply the one-shot models and create an upper bounding network with only bit-pipe connections. When developing the lower bounding network, we propose a two-step update of these models for each coupled broadcast and multiple-access channels. We demonstrate by some examples that the resulting upper bound is in general very good and the gap between the upper and lower bounds is usually not large.For relay-aided downlink scenarios, we propose a cooperation scheme by cancelling interference at the transmitter. It is indeed a symbol-by-symbol approach to one-dimension dirty paper coding (DPC). For finite-alphabet signaling and interference, we derive the optimal (in terms of maximum mutual information) modulator under a given power constraint. A sub-optimal modulator is also proposed by formulating an optimization problem that maximizes the minimum distance of the signal constellation, and this non-convex optimization problem is approximately solved by semi-definite relaxation. Bit-level simulation shows that the optimal and sub-optimal modulators can achieve significant gains over the Tomlinson-Harashima precoder (THP) benchmark and over non-DPC reference schemes, especially when the power of the interference is larger than the power of the noise.
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| 6. |
- Du, Jinfeng, et al.
(författare)
-
Lower bounding models for wireless networks
- 2013
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Ingår i: Proceedings of IEEE International Symposium on Information Theory, 2013. - : IEEE conference proceedings. ; , s. 1456-1460
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Konferensbidrag (refereegranskat)abstract
- Motivated by the framework of network equivalencetheory [1], [2], we present capacity lower bounding models forwireless networks by construction of noiseless networks whichcan be used to calculate an inner bound for the correspondingwireless network. We first extend the “one-shot” lower boundingmodel [6] to many-user scenarios, and then propose a two-stepupdate of the one-shot models to incorporate the broadcast natureof wireless transmission. The main advantage of the proposedlower bounding method is its simplicity and the fact that it can beeasily extended to larger networks. We demonstrate by examplesthat the resulting lower bounds can even approach the capacityin some setups.
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| 7. |
- Du, Jinfeng, et al.
(författare)
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Optimal Symbol-by-Symbol Costa Precoding for a Relay-aided Downlink Channel
- 2011
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Ingår i: IEEE Transactions on Communications. - : IEEE. - 0090-6778 .- 1558-0857. ; 59:8, s. 2274-2284
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we consider practical approaches to Costa precoding (also known as dirty paper coding). Specifically, we propose a symbol-by-symbol scheme for cancellation of interference known at the transmitter in a relay-aided downlink channel. For finite-alphabet signaling and interference, we derive the optimal (in terms of maximum mutual information) modulator under a given power constraint. A sub-optimal modulator is also proposed by formulating an optimization problem that maximizes the minimum distance of the signal constellation, and this non-convex optimization problem is approximately solved by semi-definite relaxation. For the case of binary signaling with binary interference, we obtain a closed-form solution for the sub-optimal modulator, which only suffers little performance degradation compared to the optimal modulator in the region of interest. For more general signal constellations and more general interference distributions, we propose an optimized Tomlinson-Harashima precoder (THP), which uniformly outperforms conventional THP with heuristic parameters. Bit-level simulation shows that the optimal and sub-optimal modulators can achieve significant gains over the THP benchmark as well as over non-Costa reference schemes, especially when the power of the interference is larger than the power of the noise.
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| 8. |
- Du, Jinfeng, et al.
(författare)
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Scalable upper bounding models for wireless networks
- 2014
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Ingår i: Proceedings of IEEE International Symposium on Information Theory. - : IEEE conference proceedings. ; , s. 241-245
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Konferensbidrag (refereegranskat)abstract
- The framework of network equivalence theory developed by Koetter et al. introduces a notion of channel emulation to construct noiseless networks as upper/lower bounding models for the original noisy network. This paper presents scalable upper bounding models for wireless networks, by firstly extending the ``one-shot'' bounding models developed by Calmon et al. and then integrating them with network equivalence tools. A channel decoupling method is proposed to decompose wireless networks into decoupled multiple-access channels (MACs) and broadcast channels (BCs). The main advantages of the proposed method is its simplicity and the fact that it can be extended easily to large networks with a complexity that grows linearly with the number of nodes. It is demonstrated that the resulting upper bounds can approach the capacity in some setups.
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| 9. |
- Du, Jinfeng, et al.
(författare)
-
Short-Message Noisy Network Coding with Partial Source Cooperation
- 2012
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Ingår i: Information Theory Workshop (ITW), 2012 IEEE. - : IEEE conference proceedings. - 9781467302234 ; , s. 144-147
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Konferensbidrag (refereegranskat)abstract
- Noisy network coding (NNC) has been shown to outperform standard compress-and-forward (CF) in networks with multiple relays and/or multiple destinations. Recently, short-message noisy network coding (SNNC) has been proved to achieve the same rate region as NNC for independent sources but with significantly reduced encoding delay and decoding complexity. In this paper, we show that when partial cooperation between source nodes is possible, by performing rate-splitting, message exchange, and superposition coding with proper power allocation at the source nodes, SNNC can achieve a strictly larger rate region than NNC. The gain comes from coherent combining at all the receiving nodes.
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| 10. |
- Du, Jinfeng, et al.
(författare)
-
Wireless multicast relay networks with limited-rate source-conferencing
- 2013
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Ingår i: IEEE Journal on Selected Areas in Communications. - : IEEE Press. - 0733-8716 .- 1558-0008. ; 31:8, s. 1390-1401
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate capacity bounds for a wireless multicast relay network where two sources simultaneously multicast to two destinations with the help of a full-duplex relay node. The two sources and the relay use the same channel resources (i.e. co-channel transmission). We assume Gaussian channels with time-invariant channel gains which are known by all nodes. The two source nodes are connected by orthogonal limited-rate error-free conferencing links. By extending the proof of the converse for the Gaussian relay channel and introducing two lemmas on conditional (co-)variance, we present two genie-aided outer bounds of the capacity region for this multicast relay network. We extend noisy network coding to use source cooperation with the help of the theory of network equivalence. We also propose a new coding scheme, partial-decode-and- forward based linear network coding, which is essentially a hybrid scheme utilizing rate-splitting and messages conferencing at the source nodes, partial decoding and linear network coding at the relay, and joint decoding at each destination. A low-complexity alternative scheme, analog network coding based on amplify-and-forward relaying, is also investigated and shown to benefit greatly from the help of the conferencing links and can even outperform noisy network coding when the coherent combining gain is dominant.
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| 11. |
- Du, Zi-Ming
(författare)
-
Biomarkers in nasopharyngeal carcinoma
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in certain areas of Southern China, Southeastern Asia and Northern Africa. Currently, evaluation of NPC prognosis is mainly based on the tumor-node-metastasis (TNM) staging system. However, NPC patients with the same clinical stage often present different clinical courses, suggesting that the TNM staging is insufficient to predict prognosis of this disease. Therefore, it is important to find molecular biomarkers, which can help clinicians to identify NPC patients with worse prognosis and develop therapeutic interventions in NPC patients. This thesis presents the identification and investigation of mechanism of several novel markers in NPC. In the first paper, Caveolin-1 (Cav-1), a major structural component of caveolae, and CD147 (also known as extracellular matrix metalloproteinase inducer, EMMPRIN), a glycoprotein, were found to be overexpressed in NPC. Both Cav-1 and CD147 expression levels correlated significantly with metastasis and poor prognosis of NPC patients. Further studies revealed that Cav-1 and CD147 enhance NPC cell migration, which is associated with MMP-3 and MMP-11 (active) secretion. The role of microRNA-155 (miR-155) is associated with oncogenesis of several human tumors. In the second paper, miR-155 was found to be upregulated in NPC cell lines and clinical samples. EBV encoded LMP1 and LMP2A could further enhance the expression of miR-155 in NPC CNE1 and TW03 cells. JMJD1A was identified as a direct target of miR-155 in NPC. Downregulation of JMJD1A was significantly correlated with N stage of the TNM classification, a lower five-year survival rate, and a lower five-year disease-free survival rate of NPC patients. Spleen tyrosine kinase (Syk) is a nonreceptor tyrosine kinase and often aberrantly expressed in human cancers. In the third paper, high expression of Syk was detected in 24% of NPC cases. High expression of Syk, resulted partly from LMP2A expression in NPC, is associated with tumor recurrence and poor prognosis of NPC patients. Human chromosome 3 (Chr. 3) contains clusters of tumor suppressor genes (TSGs) involved in many cancer types. In the fourth paper, using Not I Chr. 3 microarray, ten candidate TSGs were found in NPC. Among them, the CpG island in the promoter region of Wingless-type Mouse mammary tumor virus integration site family, member 7A (WNT7a) and the intron 1 region of Integrin α9 (ITGA9) were confirmed to be hypermethylated in NPC by bisulfite sequencing and methylation specific PCR. Demethylating agent 5-aza-2′-deoxycytidine (5-aza-CdR) treatment could restore the expression of WNT7a and ITGA9 in NPC cell lines. Furthermore, WNT7a and ITGA9 were downregulated in NPC clinical samples. As both proteins execute significant functions related to the tumor cell biology, the potential of WNT7a and ITGA9 as diagnosis or therapeutic targets for NPC should be considered.
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| 12. |
- Lu, Ming, et al.
(författare)
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Assessing the daylight and sunlight availability in high-density residential areas: a case in North-east China
- 2013
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Ingår i: Architectural Science Review. - : Informa UK Limited. - 1758-9622 .- 0003-8628. ; 56:2, s. 168-182
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the impact of building orientations, typical layouts and positions at facades on daylight and sunlight availability in high-density residential areas in North-east China. Vertical daylight factor (including sky component and reflected component) and sunlight hours along the centre building facades in three typical models were calculated using Radiance and Autodesk Ecotect Analysis. From the results the attenuation of the vertical daylight factor on the facade of each building model is explained and some empirical functions are derived. In addition, the results of sunlight analysis show the relationships between the sunlight hours, building orientations and layouts. The achieved results could be developed into design guidelines for the earlier urban planning.
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| 13. |
- Manssour, Jawad, et al.
(författare)
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Network-Coding-Aware Link Adaptation forWireless Broadcast Transmission
- 2013
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Ingår i: Proceedings of the 10th IEEE VTS Asia Pacific Wireless Communications Symposium. - : IEEE conference proceedings. ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- We present a network-coding-aware link adaptationscheme for wireless broadcast transmission, which can achievesignificantly higher throughput compared to schemes whichalways ensure correct decoding by the weakest link receiver.We evaluate the performance for the broadcast phase of a twoway relay channel based on average SNR feedback. If dynamicswitch between the bit-wise XOR network coding scheme andthe generalized multiplicative network coding is allowed, a lessthan 1% throughput loss compared to ideal network coding canbe achieved in most SNR regions, and a less than 6% throughputloss can be guaranteed regardless of link asymmetry.
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| 14. |
- Aad, G., et al.
(författare)
-
- 2011
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swepub:Mat__t (refereegranskat)
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| 15. |
- Aad, G., et al.
(författare)
-
- 2012
-
swepub:Mat__t (refereegranskat)
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