3,467 research outputs found
Modulated Unit-Norm Tight Frames for Compressed Sensing
In this paper, we propose a compressed sensing (CS) framework that consists
of three parts: a unit-norm tight frame (UTF), a random diagonal matrix and a
column-wise orthonormal matrix. We prove that this structure satisfies the
restricted isometry property (RIP) with high probability if the number of
measurements for -sparse signals of length
and if the column-wise orthonormal matrix is bounded. Some existing structured
sensing models can be studied under this framework, which then gives tighter
bounds on the required number of measurements to satisfy the RIP. More
importantly, we propose several structured sensing models by appealing to this
unified framework, such as a general sensing model with arbitrary/determinisic
subsamplers, a fast and efficient block compressed sensing scheme, and
structured sensing matrices with deterministic phase modulations, all of which
can lead to improvements on practical applications. In particular, one of the
constructions is applied to simplify the transceiver design of CS-based channel
estimation for orthogonal frequency division multiplexing (OFDM) systems.Comment: submitted to IEEE Transactions on Signal Processin
Complementary Sets, Generalized Reed-Muller Codes, and Power Control for OFDM
The use of error-correcting codes for tight control of the peak-to-mean
envelope power ratio (PMEPR) in orthogonal frequency-division multiplexing
(OFDM) transmission is considered in this correspondence. By generalizing a
result by Paterson, it is shown that each q-phase (q is even) sequence of
length 2^m lies in a complementary set of size 2^{k+1}, where k is a
nonnegative integer that can be easily determined from the generalized Boolean
function associated with the sequence. For small k this result provides a
reasonably tight bound for the PMEPR of q-phase sequences of length 2^m. A new
2^h-ary generalization of the classical Reed-Muller code is then used together
with the result on complementary sets to derive flexible OFDM coding schemes
with low PMEPR. These codes include the codes developed by Davis and Jedwab as
a special case. In certain situations the codes in the present correspondence
are similar to Paterson's code constructions and often outperform them
Sub-Nyquist Channel Estimation over IEEE 802.11ad Link
Nowadays, millimeter-wave communication centered at the 60 GHz radio
frequency band is increasingly the preferred technology for near-field
communication since it provides transmission bandwidth that is several GHz
wide. The IEEE 802.11ad standard has been developed for commercial wireless
local area networks in the 60 GHz transmission environment. Receivers designed
to process IEEE 802.11ad waveforms employ very high rate analog-to-digital
converters, and therefore, reducing the receiver sampling rate can be useful.
In this work, we study the problem of low-rate channel estimation over the IEEE
802.11ad 60 GHz communication link by harnessing sparsity in the channel
impulse response. In particular, we focus on single carrier modulation and
exploit the special structure of the 802.11ad waveform embedded in the channel
estimation field of its single carrier physical layer frame. We examine various
sub-Nyquist sampling methods for this problem and recover the channel using
compressed sensing techniques. Our numerical experiments show feasibility of
our procedures up to one-seventh of the Nyquist rates with minimal performance
deterioration.Comment: 5 pages, 5 figures, SampTA 2017 conferenc
Doppler Tolerance, Complementary Code Sets and the Generalized Thue-Morse Sequence
We generalize the construction of Doppler-tolerant Golay complementary
waveforms by Pezeshki-Calderbank-Moran-Howard to complementary code sets having
more than two codes. This is accomplished by exploiting number-theoretic
results involving the sum-of-digits function, equal sums of like powers, and a
generalization to more than two symbols of the classical two-symbol
Prouhet-Thue-Morse sequence.Comment: 12 page
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