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This paper investigates path loss characteristics for Vehicle-to-Infrastructure (V2I) communications in urban and suburban scenarios. We carried out measurements at 5.9 GHz. The transmitter antenna heights are 3.5 m and 1.5 m and the position of the receiver antenna is on the roof of the car. Then we analyzed the path loss characteristics by using the measured data. The results are helpful for the...
This paper focuses on a channel testing scheme based on public LTE network for high-speed scenario. To simplify the deployment of channel testing for high-speed scenario, public LTE CRS in downlink can be utilized so that setting up a transmitter is avoided. A receiver system was designed and the testing was carried out on a high-speed train. Before the field testing a verification for receiver via...
This paper presents an adaptive relaying scheme for an asymmetric two-way relaying system in which physical-layer network coding (PNC) is applied. In particular, we study a demodulate-and-forward (DmF) relay and indicate that PNC may yield to other schemes in some specific channel states, such as a case when the received powers of the two sources differ much in the uplink channel. To tackle the problem...
With the fast development of high-speed railways, the need for wireless communication to satisfy secure demand of train and application demand of passengers has become evident.As a part of large- scale propagation effects, shadow fading is of great importance to design hand-over algorithm, and to evaluate macro diversity gain in wireless communications. This paper offers an investigation on the cross-correlation...
Two-way relaying systems have shown its advantage in enhancing the capacity performance in literature. However, there are many difficulties in the practical implementation. In this paper, an effective mapping algorithm of superposed signals is proposed based on the Binary Phase Shift Keying (BPSK) modulation. It is rather more suitable for implementation than the existing scheme derived from the Minimum...
Amplify-and-forward (AF) based two-way relaying (TWR) has shown its sum rate advantage over AF based one-way relaying (OWR) in the literature. However, this advantage can not be achieved in some cases. In this paper, we evaluate the sum rates of AF based OWR/TWR and provide the relationship with respect to the relative channel gains and the relative transmit power of the three nodes, i.e., the relay...
With the rapid development of high-speed railway, the train speed can reach up to 350 km/h. Much more technical demands for high-speed railway mobile communication system are put forward. As the next generation wireless communication technology of 3GPP, Long Term Evolution for railway, known as LTE-R, is proposed to provide railway communication services including railway control, passenger services,...
In this paper, we present packet data transmission process and analyze packet data random access mechanism with discrete frame format according to Slotted-ALOHA protocol in Terrestrial Trunked Radio (TETRA) network. A mathematical model of packet data random access is built for further simulations based on MATLAB. Given the simulations results, we achieve the performance indicator of access delay,...
The next-generation LTE standards operating on high-speed trains faces the problems about fast time-selective and frequency-selective channel. Precoding relying on accurate channel information at the transmitter or receive feedback will be less effective in such scenarios. Based on WINNER D2a channel model for high-speed railway, double differential space- frequency precoding scheme is proposed. Double...
A frequency-timing synchronization scheme for the downlink of filtered multitone modulation (FMT) based Terrestrial Trunked Radio (TETRA) system is presented. To achieve high-rate data transmission and better transmission quality, TETRA2 has been proposed in recent years. However, there are serious issues with the new wide-band TETRA system in frequency-timing synchronization. TETRA mainly specifies...
The (16,5) Reed-Muller(RM) code is used in CCH-Q in TETRA II. The majority-logic algorithms are introduced in this paper firstly, which include Massey's majority-logic algorithm, Reed's majority-logic algorithm and Rodulph's majority-logic algorithm for (16,5) RM code. And then a modified Massey's majority-logic decoding algorithm is led out to improve the ability of error-correcting. Different decoding...
TETRA (Terrestrial Trunked Radio) is a digital trunking communication standard which is recommended by ETSI (European Telecommunications Standards Institute) and has been widely used in the world. It has been used in many areas such as underground, fire protection, police system. SDR (Software Defined Radio) is a technology which just changes the software without changing the hardware to implement...
TETRA is a digital trunked communication system. TETRA II adopt Filtered Multitone Modulation (FMT) multicarrier scheme to provide high speed data service. This paper introduce modulation parameters which are defined in TETRA II standard and efficient implement, then simulate and analyze the BER performance in AWGN and multipath channel.
The core of channel coding in TETRA V+D standard is RCPC code, besides that, another core coding PCCC is brought for high-speed data technology TEDS in TETRA Release 2. This paper firstly leads out the error control structures of TETRA logical channels, and then introduces the specific coding procedure of RCPC and PCCC codes. Simulations and Analysis about error correction performance of RCPC and...
Expandable slotted tubulars have been found to improve well production, reduce sand production and thereby reduce well costs compared with conventional approaches to sand control. While performing these completion operations the maximum running hook loads and static drag encountered during pre- and post-expansion process are indispensable for making appropriate well-completion decisions. Traditionally,...
In order to ensure service quality of communication in high mobile speed, the improvement of receiver's performance is of great importance. The paper takes high-speed communication as the researching background. Algorithms for equalizing intersymbol interference and Doppler Effect are studied for data-aided transmission. The inputs of equalization are improved by the mended derotation method. Take...
Progressive Edge-Growth (PEG) algorithm is a novel approach for construction of low-density parity-check (LDPC) codes with large girth. However, PEG algorithm ignores the effect of the number of shortest cycles. In this paper, we propose a modified PEG algorithm with Polynomial of Cycle, which achieves not only large girth, but also minimizes the number of shortest cycles significantly. Simulation...
LDPC (low-density parity-check) codes have a good performance close to the Shannon limit. To make full error-correcting performance, soft information is used in iterative decoding algorithm. For different types of modulation, there are different expressions of channel soft information. In this paper, we propose approaches for computing channel soft information precisely for BPSK, QPSK, 16QAM, instead...
Taking RS encoder in CMMB system for example, we proposed an improved algorithm according to the method of bit-parallel multiplier based on dual basis. The new algorithm can achieve a higher rate, and the RS encoder can be applied in a wide range of systems when implemented in FPGA.
This paper introduces a new algorithm in Ereka-147 digital audio broadcasting (DAB) symbol timing offset estimation. The proposed algorithm performs robust operation and low complication in symbol timing offset estimation. The performance of this algorithm is carried out under AWGN and multipath fading channel.
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