The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
M2M wireless communications network is a novel research topic, while the green communications is advocated in the subject, which can be reflected by the use of renewable energy. In this paper, we discuss the M2M network together with green communications. We design the flow control and transmission algorithm for the M2M network where there exist nodes using renewable energy. The algorithm need not...
This paper investigates joint complex diversity coding (CDC) and error control coding (ECC) to increase diversity gains across multiple antennas, OFDM blocks, and OFDM sub-carriers. A general diversity analysis for joint CDC and ECC based space-time-frequency codes (STFCs) is provided. The mapping designs from ECC to CDC are crucial for efficient exploitation of the diversity potential. This paper...
In this paper, we study an enhanced subspace based approach for the mitigation of multiple access interference (MAI) in direct-sequence code-division multiple-access (DS-CDMA) systems over frequency-selective channels. Blind multiuser detection based on signal subspace estimation is of special interest in mitigating MAI in CDMA systems since it is impractical to assume perfect knowledge of parameters...
Cognitive Radio (CR) is considered as an effective technology for alleviating the spectrum shortage problem by enabling secondary users to utilize vacant spectrum allocated to a primary user (PU). IEEE 802.22 which is the first standard based on CR is developed to increase the efficiency of TV bands. However the physical layer security of IEEE 802.22 has been studied rarely. In this paper, we propose...
A frequency adaptive detect and avoid (DAA) design method based on frequency band encoding is presented for narrow band interference suppression. Gaussian derivative pulse is considered as the ultra-wideband (UWB) original pulse because of its characteristics of zero DC component, easy generation and meeting with the Federal Communications Commission (FCC) indoor and outdoor spectral mask. Simulation...
Low density parity check code is a kind of high-performance linear block code. It has excellent performance which is near the Shannon limit. LDPC has low decoding complexity, free structure and receives extensive attention. The typical decoding algorithm of LDPC is LLR BP algorithm, which is also called “sum-product algorithm”. LLR BP algorithm is the best algorithm at present. But it needs complex...
This article puts forward a method for codebook design to support beamforming mechanism in a 60GHz millimeter-wave wireless communication environment. The codebook is designed with only phase shifting but not any amplitude adjustment to meet the low power consumption requirement. IEEE802.15.3c beam MRA (main response axis) directions are taken as the original version to make curve fitting, so that...
There is an increasing tendency that elderly people live separately from their children or relatives with the advance of low-birth-rate, aging society and the changes in living environment. Under such circumstances, a number of systems to remotely watch vulnerable people by utilizing sensor devices and communication functions have been proposed. Existing systems to watch vulnerable people are, however,...
In Japan, senior citizen population is rapidly increasing as a result of the progress in super-aging society, while many younger generation people live separately from their elderly relatives under the current societal environment. Nevertheless, young people often have a desire for constantly watching health conditions of their elderly relatives even remotely. In this paper, we propose a system to...
In recent years, there have been significant breakthroughs in wireless communication systems design based on the multiple-input multiple-output (MIMO) concept. Exploiting the channel state information at the transmitter (CSIT) can improve the link performance. Thus, MIMO precoding has been an active research area for wireless communications. By specifying a precoding matrix with full CSIT, one can...
With a possible exhaustion of global IPv4 addresses, shifting to IPv6 is thought to be inevitable. However, when the shifting to IPv6 actually occurs, network topology could be inferred from addresses in the organization. Thus, as a means to conceal network topology, various methods, including the use of Mobile IPv6 and the setting-up of routers for host routes, are being proposed. However, redundant...
In this paper, we propose a supply current testable resistor string DAC of decoder type whose area overhead is small and a supply current test method. Open defects and short ones in the DAC can be detected by the test method with about 50% of the exhausted test vectors. It is shown by some experiments that most of the targeted defects in our testable DACs of 4 and 8 bits can be detected by the test...
In this work, we propose a novel algorithm to combat the clipping noise in Interleave-division multiple access (IDMA) which inherits a peak-to-average power ratio (PAPR) problem especially in large number of multiple accesses. Clipping transmission is efficiently applied to reduce the PAPR to cause the clipping noise which is a weak tradeoff [1][2] to its performance. The proposed algorithm consists...
Coordinated Multi-Point transmission (CoMP) has been recognized as one of the most promising technologies in the 4th generation (4G) cellular systems. It can significantly increase the spectral efficiency by combining the data from different eNBs. However, the benefits come at the cost of the increased feedback overhead. In the downlink frequency division duplex (FDD) systems, UEs need to feedback...
Speech recognition is the key to realize man-machine interface technology. In order to improve the accuracy of speech recognition and implement the module on embedded system, an embedded speaker-independent isolated word speech recognition system based on ARM is designed after analyzing speech recognition theory. The system uses DTW algorithm and improves the algorithm using a parallelogram to extract...
Digital Video Broadcasting — Terrestrial for Second generation (DVB-T2) was released, for the purpose of supporting High Definition Television (HDTV) services. Although DVB-T2 leads to performance improvement by introducing state-of-the-art communication techniques, the introduction of such communication techniques has become problems in implementing the system. Multiple Physical Layer Pipe (PLP),...
In this paper, the optimal power control strategies under four different types of power constraints are derived via convex optimization to maximize the ergodic capacity of secondary system based on spectrum sharing while guaranteeing QoS of the primary system transmission. The interference from primary user to secondary system is simultaneously considered in the analysis process besides the interference...
A new adaptive Kalman filtering algorithm for dual-frequency navigation with carrier phase is presented. By reducing the filtering order after full-order initialization, this algorithm saves the extra computational cost brought by carrier phase observations. The improved adaptation of state covariance matrix in reduced-order processing also improves filtering precision and robustness. Finally applications...
In this paper a procedure for deconvolving signals in a Discrete Wavelet Transform (DWT) framework is applied to the estimation of impulse responses of fast-fading communications channels. Specifically, the effects of using several different wavelets on the performance of such wavelet-domain channel estimation is investigated. Monte Carlo simulations are performed using eight different wavelets. The...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.