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We consider the problem of optimal power control for quality-of-service-assured wireless communication. The quality of service (QoS) measures of our consideration are a triplet of data rate, delay, and delay bound violation probability. Our target is to develop power control laws that can provide delay guarantees for real-time applications over wireless networks. The power control laws that aim at...
Multiple-input multiple-output (MIMO) systems operating at frequencies in the upper VHF and lower UHF region is attractive for peer-to-peer communication applications where robustness is of high importance, e.g., in tactical networks and emergency response systems. When designing and evaluating such systems, knowledge of realistic propagation conditions is required. This paper presents results from...
In this paper we investigate a methodology named channel selection with the aim of balancing the multiple input multiple output (MIMO) advantage and the complexity of node cooperations for wireless sensor networks (WSN). In respect of cross-layer design, we propose the Maximum Spanning Tree Searching (MASTS) algorithm to select a set of subchannels that always provide a path connecting all sensors...
The Army is evaluating the potential use of military X-band, in support of satellite on- the-move (SOTM) missions, to satisfy much needed war-fighting bandwidth. Over the next 5 years, the Wideband Global SATCOM (WGS) constellation will be placed in orbit. It will consist of a geosynchronous constellation of at least five X and Ka capable satellites. The WGS X- band payload is significantly more powerful...
Recent research on network coding (NC) shows that the wireless NC can improve the network throughput in multi-hop wireless ad hoc networks since it can exploit not only the broadcast nature of the wireless channel but also the native physical-layer coding ability by mixing simultaneously arriving radio waves at relay nodes. This paper characterizes the throughput gains of two wireless NC schemes,...
In-network data aggregation is an effective method to reduce the amount of data transmitted and therefore saves energy consumption in sensor networks. However, data aggregation removes the integrity of original data and thus increases the damage of data falsification attack. This paper proposes four new methods that select a subset of nodes as aggregators in a sparse and dynamic fashion to frustrate...
Future variants of unattended Networked Munitions and Ground Sensors will be remotely deployed tens of kilometers forward of the control point. Systems like the next generation of the Intelligent Munitions System (IMS) will provide a means to dominate an area on the battlefield via remote control and prevent the passage of enemy forces while allowing for the safe passage of friendly forces by providing...
Non-binary forward error correction (FEC) coding in conjunction with M-ary hyper phase-shift keying (MHPSK) is considered in order to improve the robustness of a satellite communications uplink. MHPSK is a spectrally efficient modulation technique that uses four orthonormal basis functions to increase the distance between different symbols in the signal space. Spectral efficiency and probability of...
In this paper, we consider the multicast channel in a cellular network wherein all the users within a cell request a common information stream from the base station. In addition to data streaming this can also model control channels in the cell as opposed to the regular data channels used for user specific information transmission. While the multicast transmission in a single cell environment has...
The use of Frank waveform codes in radar applications is well known. These codes are phase modulation based, with the number of phase steps dependent on the order of the code. Amplitude shaping techniques are applied to the modulation bits to reduce the sidelobe levels and constrain the bandwidth of the transmitted signal. This combination of amplitude shaping and phase modulation of the waveform...
We describe wireless network utility maximization, WNUM, and compare its performance to traditional NUM along the dimensions of rate, delay and reliability under flat fading. Both coded and uncoded links are considered as are networks with interfering links. In each case, WNUM is shown to offer superior performance in simulations operating under Rayleigh fading due to its ability to adapt to changing...
Performance of uncoded adaptive modulation (UAM) and adaptive coded modulation (ACM) enabled by the long-range prediction (LRP) that utilizes data-aided noise reduction (DANR) is investigated for rapidly varying mobile radio channels. Due to improved prediction accuracy and low pilot rate, the DANR-aided LRP outperforms previously proposed prediction methods that rely on oversampled pilots to achieve...
In this paper, for independent or concurrent anti-jamming and low probability of detection performance evaluations, a single varying paired and multiple paired fixed collocated jammer/interceptors scenario is explored with real sine type (sin(x)/x) antenna patterns being considered for the communicators. Whenever multiple collocated jammer/interceptors are considered, we can observe interesting "smoothed"...
In a hostile environment the adversarypsilas antenna can detect a transmitter when the signal to noise ratio at the adversary antenna is large enough. A directional antenna concentrates transmit power into certain direction and forms a directional beam pointing to the receiver, so it can decrease the radiation region in which nodes could receive the electromagnetic signals with high quality. This...
Multi-mode power loading is an attractive power loading technique since it avoids iterative procedures and periodic updates of a threshold value in order to find the best power loading configuration. Simultaneously, multi-mode power loading achieves comparable spectral efficiency to optimal waterfilling with full channel state information (CSI) using only N feedback bits, where N is the number of...
A key feature of a cognitive radio (CR) is a reliable spectrum sensing technique which enables the CR to detect the so-called white spaces in the frequency band. This allows opportunistic access of the unlicensed (secondary) users to these white spaces without causing undue interference to licensed (primary) users. In many scenarios the CR may operate in a multipath fading environment where spectrum...
In order to opportunistically utilize the licensed frequency band, secondary radios need to sense the spectrum for the presence of the primary radio. Non-cooperative and cooperative sensing schemes have been reported in the literature. In this paper, an improved spectrum sensing scheme, where cooperative sensing is performed only selectively according to a predefined criterion, is proposed. Our studies...
We develop bandwidth-efficient serially concatenated coded (SCC) continuous phase modulation (CPM) techniques for aeronautical telemetry. The concatenated code consists of an inner and an outer code, separated by an interleaver in most configurations, and is decoded using relatively simple near-optimum iterative decoding algorithms. CPM waveforms such as shaped-offset quadrature phase shift keying...
We investigate the secrecy capacity of an ergodic fading wiretap channel in which the main channel is correlated with the eavesdropper channel. In this study, the full Channel State Information (CSI) is assumed, and thus the transmitter knows the channel gains of the legitimate receiver and the eavesdropper. By analyzing the resulting secrecy capacity we quantify the loss of the secrecy capacity due...
This paper reviews the driving factors that affect performance gains in wireless networks when receivers are enabled by multiuser detection (MUD). Assuming the many-to-one, Gaussian multiple-access channel, we compare the capacity of a jointly optimal MUD receiver with the single user match filter using TDMA, FDMA and orthogonal CDMA access schemes. Comparisons are made under both equal power and...
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