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In this letter, an adaptive spatial modulation (ASM) transmission scheme is proposed to achieve better system performance under a fixed data rate. The proposed scheme is based on a developed modulation order selection criterion (MOSC), so as to minimize the conditioned pairwise error probability (PEP) for each channel realization. Furthermore, the special information-conveying mode of spatial modulation...
Wireless communication is one of the most vibrant areas in the communication field today. In the last few years, the telecommunication industries development has focused on an intensive use of broadband systems, with high quality features. For this issue, new technologies with high transmission abilities have been designed. There is one fundamental aspects of wireless communication that make the problem...
The sphere decoding algorithm for signal transmitted on multiple antennas channel is considered. In this paper, the preprocessing stage is analyzed in order to seek a reduced complexity and some improvements are made to enhance the performance. The computer simulation results show that the improved algorithm by applying Pohst Enumeration with selected initial radius is more efficient than that by...
Adaptive modulation is an effective means to make full use of wireless channel capacity and average spectral efficiency in multiple input multiple output systems. Based on the optimal bit allocation algorithm in MIMO systems, a new algorithm was proposed which calculate the total power constraint for each sub-channel to determine the modulation mode by rounding down means. Then according to the residual...
Multiuser multiple-input multiple-output (MIMO) downlink (DL) transmission schemes experience both multiuser interference (MUI) as well as inter-antenna interference. However, instead of treating all the users jointly as in zero-forcing (ZF) multiuser transmission techniques, the investigated singular value decomposition (SVD) and geometric mean decomposition (GMD) assisted DL multiuser MIMO systems...
That the environment of distribution brings in distortion in an ideal signal, radiated a transmitter, both as a result of addition of noises and by distortion of useful signal. Noises of radio channel include base-line noise of ether, parasite radiations of industrial electrical equipment and other extraneous radiations.
This article at first introduces the development of the channel coding technology driven by the Shannon's theory, and the tendency that the coding and modulation will be combined. Then it elaborates on the channel coding problems under the wireless channel. At last it discusses the development direction of the coding technology, that is, when considering the specific wireless communication environment,...
Opportunistic or cognitive radio system are a key technology able to enable reconfigurability and flexibility of wireless systems in the railway domain in order to answer requirements such as system availability, robustness, and traffic heterogeneity. These technologies will allow dynamic spectrum allocation and very often spectrum reuse especially in rural areas. They required an accurate knowledge...
There are a few core technologies to enable high-performance 4th generation (4G) broadband wireless communication system. A multiple input multiple output (MIMO) provides high-rate transmission through expended channels by multiple array antennas in both sender and receiver side. Also orthogonal frequency division multiplexing (OFDM) is well-known as the most appropriate technique for high data rate...
Adaptive modulation and coding (AMC) is a powerful technique to enhance the link performance by adjusting the transmission power, channel coding rates and modulation levels according to channel state information. In order to efficiently utilize the AMC scheme, an accurate signal-to-noise ratio (SNR) value is normally required for determining the AMC level. In this paper, we propose a simple method...
An efficient and flexible air interface is the necessary condition for enabling high data rates next generation wireless systems. A practical answer to this need consists in exploiting channel state information at the transmitter for an adaptive and efficient use of the available radio link resources. This paper contributes with a novel strategy for the allocation of the sub-carrier transmit power...
In order to analyze the ambiguity function of WiMAX signals and evaluate their suitability for passive radar, the first step should be the generation of WiMAX transmission signal, including random data generation, modulation, Space Time Block Coding (STBC), preamble generation for synchronization and channel estimation, frame combination and Orthogonal Frequency Division Multiplexing (OFDM) modulation...
This paper proposes a new concept of multiple-input multiple-output (MIMO) detection, aiming at minimizing the average computational cost. The detection methods, according to the estimated channel state information, are adapted to deliver just acceptable error rate. Performance of two popular MIMO detectors is analyzed. Based on these analyses, a channel adaptive MIMO (CA-MIMO) receiver with a novel...
In future cellular radio such as IMT-advanced systems, we will encounter a difficulty in sending uplink signals. This is because transmit power is limited by a battery in a terminal and we need higher transmit power to accommodate a wider frequency bandwidth in a higher frequency band. Virtual MIMO-based cooperative communication is expected to be a key technology to solve this problem. Especially,...
In this paper, link adaptation, which dynamically selects modulation level and coding rate according to the channel condition, and several multi-input multi-output (MIMO) transmission modes are studied. As we know, the subchannels' signal-to-noise radio (SNR) by singular value decomposition (SVD) are unequal, which requires different modulation and coding schemes (MCS) to maximize the throughput....
This paper investigates the use of MIMO techniques in a multihop wireless network. We consider that the link between any two nodes can be established using one of two different MIMO schemes and one of many modulation orders. Computer simulations were carried out in order to identify the best configuration for different channel conditions. Then, the source-to-destination route, which may be composed...
In this paper system level performance evaluation of channel aware schedulers that apply previously presented multiple input-multiple output (MIMO) link adaptation algorithms is given. The analyzed schedulers operate in single-user (SU) and in multi-user (MU) mode, and adapt either only modulation and coding scheme, or MIMO scheme in addition. The performance evaluation is done by comparative analysis...
In this paper we present the mutual information of a bit-interleaved V-BLAST space-time architecture. We assume interference cancellation by successive detection using MMSE equalizers without decoding of the channel codes. The mutual information is dependent on the MIMO channel realization and the detection order. However, the mutual information is very similar to that of an AWGN channel when plotted...
We propose a jointly designing transceiver for time-varying multiple-input multiple-output (MIMO) systems. Based on geometric mean decomposition (GMD), the scheme decomposes a MIMO channel into parallel subchannels with identical capacities and each subchannel meets certain BER constraints. Thus the power loading and modulation/demodulation process are particularly simplified because of the identical...
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