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.
In this paper, we propose a cross-layer optimization approach that exploits retransmission diversity in wireless CDMA communications. Conventionally, data packets that are not correctly detected are usually dropped. These dropped packets can be used to help data packet detection. By exploiting all the retransmitted packets, data packets can be correctly detected with higher probability. The proposed...
In this paper, the design of a compact planar bandpass filter above a defected ground plane is presented. The filter is designed as a combination of microstrip resonators and exploits the properties of a planar electromagnetic bandgap (EBG) structure patterned unto the ground plane of the printed circuit board material to provide a very wide stopband of up to 5 times the fundamental frequency. The...
In this paper, we address the issue of transmission power control (TPC) in wireless ad hoc networks. Power control plays an important role in energy saving and network performance enhancement. However, the existing TPC schemes either face the problem of hidden and exposed terminal or have additional hardware requirements. We propose a novel distributed power control protocol, called Receiver Initiated...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a...
This paper investigates the effective gain of antennas in indoor channels. A metric called instantaneous effective gain is proposed, and a multiple-cluster 3D channel model is used to facilitate the proposed antenna effective gain. In the multiple-cluster channel model, Laplacian and double exponential distribution are utilized to model azimuth and elevation signal power distribution respectively,...
The ergodic capacity of single input multiple output (SIMO) wireless communication systems over Nakagami-m fading channels is available in the literature for the case of identically independent distributed (i.i.d.) subchannels. However, the non- identically independent Nakagami-m case is more practical and has not been considered in the literature. In this paper, we derive an analytical expression...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
In this paper, we consider a new channel probing scheme for opportunistic scheduling in the uplink of orthogonal frequency division multiplexing (OFDM)-based wireless systems. To reduce signaling overhead for the probing, we consider a two-step channel probing process; called pre-probing and mainprobing. Good subchannels are first estimated through the pre-probing process using a probing signal transmitted...
In this paper, a novel approach using frame-based iterative channel fading parameters estimation technique from the received data sequence exploiting orthogonal property of the space-time block (STB) code is proposed. For practical implementation of STB code, the receiver requires to estimate these parameters. Regarding this type of estimation, the inherent orthogonal nature of STB code can be exploited...
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.