718 research outputs found
Mapping DSP algorithms to a reconfigurable architecture Adaptive Wireless Networking (AWGN)
This report will discuss the Adaptive Wireless Networking project. The vision of the Adaptive Wireless Networking project will be given. The strategy of the project will be the implementation of multiple communication systems in dynamically reconfigurable heterogeneous hardware. An overview of a wireless LAN communication system, namely HiperLAN/2, and a Bluetooth communication system will be given. Possible implementations of these systems in a dynamically reconfigurable architecture are discussed. Suggestions for future activities in the Adaptive Wireless Networking project are also given
Timing and Carrier Synchronization in Wireless Communication Systems: A Survey and Classification of Research in the Last 5 Years
Timing and carrier synchronization is a fundamental requirement for any wireless communication system to work properly. Timing synchronization is the process by which a receiver node determines the correct instants of time at which to sample the incoming signal. Carrier synchronization is the process by which a receiver adapts the frequency and phase of its local carrier oscillator with those of the received signal. In this paper, we survey the literature over the last 5 years (2010–2014) and present a comprehensive literature review and classification of the recent research progress in achieving timing and carrier synchronization in single-input single-output (SISO), multiple-input multiple-output (MIMO), cooperative relaying, and multiuser/multicell interference networks. Considering both single-carrier and multi-carrier communication systems, we survey and categorize the timing and carrier synchronization techniques proposed for the different communication systems focusing on the system model assumptions for synchronization, the synchronization challenges, and the state-of-the-art synchronization solutions and their limitations. Finally, we envision some future research directions
A low-cost time-hopping impulse radio system for high data rate transmission
We present an efficient, low-cost implementation of time-hopping impulse
radio that fulfills the spectral mask mandated by the FCC and is suitable for
high-data-rate, short-range communications. Key features are: (i) all-baseband
implementation that obviates the need for passband components, (ii) symbol-rate
(not chip rate) sampling, A/D conversion, and digital signal processing, (iii)
fast acquisition due to novel search algorithms, (iv) spectral shaping that can
be adapted to accommodate different spectrum regulations and interference
environments. Computer simulations show that this system can provide 110Mbit/s
at 7-10m distance, as well as higher data rates at shorter distances under FCC
emissions limits. Due to the spreading concept of time-hopping impulse radio,
the system can sustain multiple simultaneous users, and can suppress narrowband
interference effectively.Comment: To appear in EURASIP Journal on Applied Signal Processing (Special
Issue on UWB - State of the Art
Orthogonal Constant-Amplitude Sequence Families for System Parameter Identification in Spectrally Compact OFDM
In rectangularly-pulsed orthogonal frequency division multiplexing (OFDM)
systems, constant-amplitude (CA) sequences are desirable to construct
preamble/pilot waveforms to facilitate system parameter identification (SPI).
Orthogonal CA sequences are generally preferred in various SPI applications
like random-access channel identification. However, the number of conventional
orthogonal CA sequences (e.g., Zadoff-Chu sequences) that can be adopted in
cellular communication without causing sequence identification ambiguity is
insufficient. Such insufficiency causes heavy performance degradation for SPI
requiring a large number of identification sequences. Moreover,
rectangularly-pulsed OFDM preamble/pilot waveforms carrying conventional CA
sequences suffer from large power spectral sidelobes and thus exhibit low
spectral compactness. This paper is thus motivated to develop several order-I
CA sequence families which contain more orthogonal CA sequences while endowing
the corresponding OFDM preamble/pilot waveforms with fast-decaying spectral
sidelobes. Since more orthogonal sequences are provided, the developed order-I
CA sequence families can enhance the performance characteristics in SPI
requiring a large number of identification sequences over multipath channels
exhibiting short-delay channel profiles, while composing spectrally compact
OFDM preamble/pilot waveforms.Comment: 15 pages, 4 figure
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