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In the mobile NW, rapid growth of data traffic observed in not only China and Japan, but also in world widely. Increasing of smart-phones and attraction of video-contents are current origin of the data traffic growth. In near future, tethering and M2M communications are also going to make the traffic increase. Requirement to our mobile NW to be with larger capacity is very strong and urgent.
Considering the challenges of network heterogeneity and spectrum inefficient usage, the future wireless networks should have the intelligent network information awareness, flexible spectrum management, dynamic network reconfiguration abilities. The concept of cognitive wireless network (CWN) has been proposed that aims at improving radio resources utilization by taking advantage of unused licensed...
Probably the most influential recent change affecting how we use communications has been the iPhone - and this change has been as significant as the introduction of the fax or the mobile phone itself.
Machine to Machine communications (M2M, also known as Internet of Things (IoT)) aims to enable interactions between smart objects ranging from sensors to actuators and robots and smart meters…, with or without human intervention. It has its origin in control and data acquisition systems. Recent developments in areas such as wireless communications, sensing and actuation have given it a new impetus...
This talk will be introducing the European Framework Program and the Co-financing R&D supporting policies. Prof. Potts will talk about the end of the FP7 and initial plan of the FP8.
The use of TV White Space spectrum on a secondary, unlicensed basis has been of great interest in academia, industry and regulatory bodies worldwide. Proposed applications have included residential data transfer and content streaming, and rural broadband. In the US, the FCC has published rules for unlicenced devices in the TV bands, while in the UK, Ofcom has released statements on the subject. Central...
In this talk, after a brief introduction of the cognitive radio (CR) technology, we focus on several important technical aspects of CR research. Based on my previous CR-related research work, we mainly cover three issues: spectrum sensing, medium access, and routing, which correspond to the traditional three system layers: PHY, MAC, and Network layers. Here the difference from traditional layered...
The FCC issued its first Report and Order in September 2001 on Software-Defined Radio. It commissioned a follow-on inquiry on SDR security issues and another on the potential for unlicensed usage of TV spectrum, facilitated by software radio technology. Spectrum managers in Europe, USA and Asia held a regulators forum in the UK in September 2003, which reviewed SDR approaches and the potential regulatory...
The traditional Femtocell shares the same licensed frequency band with Macrocell, thus introducing cross-tier interference. Interference mitigation between the Femtocell and Macrocell is considered to be one of the major challenges in Femtocells Network. In this paper, the released TV spectrum by the digital switchover named TV White Space (TVWS) is proposed to reduce the interference for the LTE...
In this paper, a novel signal detection scheme is proposed for correlated multiple input multiple output(MIMO) system based on Dempster-Shafer (D-S) evidence theory. The geometrical MIMO model is used for the correlated MIMO system. The focal-element-set (FES) is used to describe the uncertainty for the decision statistics, and the corresponding basic-probability- assignment (BPA) of FES is the likelihood...
An accurate technique for timing and frequency synchronization of multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed in this paper. A new preamble signal which adapts to the MIMO-OFDM synchronization, is derived based on GCL sequences. The carrier frequency offset (CFO) estimation is obtained through taking double correlation operations on the...
More and more CPU-based SDR systems appear in recent two years. Such system requires high speed real-time signal processing. In this paper, we present our effort on the speed optimization of Turbo decoder, the most computation-demanding module in all baseband modules. We jointly consider the algorithm parallelism and the processor architecture. Single Instruction Multiple Data (SIMD) instruction is...
The ultra-wideband (UWB) wireless communication has become a hotspot in current researches, which faces new challenges at the same time. One novel ultra-wideband microstrip antenna is proposed, and a U-shaped slot is cut in the radiation patch to obtain the band-notch function, and the results are simulated by using electromagnetic simulation software CST MWS (CST microwave studio). Experimental results...
In Multiple-In Multiple-Out (MIMO) Broadcast systems with limited feedback, when receivers are equipped with multiple antennas, the so-called quantization error of channel direction matrix was unavoidably introduced. This quantization error will result in the reduction of system capacity since it was referenced in the beamforming design. In this paper, we proposed a robust beamforming method based...
As the development of next-generation wireless broadband cellular networks, base station (BS) cooperation has become a promising tool to increase the per-cell spectral efficiency as well as cell-edge user throughput. In this paper, we introduce a new multi-cell cooperation strategy, where each cooperating BS simultaneously serves two co-channel users, one from the cell edge and the other from the...
By using radius of decision region, an approximate formula for word error rate (WER) of Turbo-like codes is presented in [1]. The approximate formula has a simple form of Gaussian Q-function with multiple arguments including the signal to noise ratio (SNR), the code length, and two parameters determined by the code structure and the decoding algorithm. This formula makes it possible to theoretically...
In this paper we propose a novel limited feedback scheme based on local limited feedback combined with SLNR precoding and Quantization-based-Combining (QBC) in downlink Coordinated-Beamforming (CB) systems. The channels of serving cell and coordinated cells are quantized based on QBC technology. Due to more accurate channel quantization, the proposed scheme achieves considerable improvement over the...
Coherent detection and demodulation need channel state information at receivers for orthogonal frequency division multiplexing systems. Conventional channel estimations, such as least squares (LS), are widely adopted under the assumption of rich multipath. Recently, numerous physical measurements have verified that many wireless multipath channels encountered in practice tend to exhibit sparse structures...
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