10,369 research outputs found
Performance Analysis of Multi-Antenna Relay Networks over Nakagami-m Fading Channel
In this chapter, the authors present the performance of multi-antenna selective combining decode-and-
forward (SC-DF) relay networks over independent and identically distributed (i.i.d) Nakagami-m fading
channels. The outage probability, moment generation function, symbol error probability and average
channel capacity are derived in closed-form using the Signal-to-Noise-Ratio (SNR) statistical character-
istics. After that, the authors formulate the outage probability problem, optimize it with an approximated
problem, and then solve it analytically. Finally, for comparison with analytical formulas, the authors
perform some Monte-Carlo simulations
Achieving full diversity in multi-antenna two-way relay networks via symbol-based physical-layer network coding
This paper considers physical-layer network coding (PNC) with M-ary phase-shift keying (MPSK) modulation in two-way relay channel (TWRC). A low complexity detection technique, termed symbol-based PNC (SPNC), is proposed for the relay. In particular, attributing to the outer product operation imposed on the superposed MPSK signals at the relay, SPNC obtains the network-coded symbol (NCS) straightforwardly without having to detect individual symbols separately. Unlike the optimal multi-user detector (MUD) which searches over the combinations of all users’ modulation constellations, SPNC searches over only one modulation constellation, thus simplifies the NCS detection. Despite the reduced complexity, SPNC achieves full diversity in multi-antenna relay as the optimal MUD does. Specifically, antenna selection based SPNC (AS-SPNC) scheme and signal combining based SPNC (SC-SPNC) scheme are proposed. Our analysis of these two schemes not only confirms their full diversity performance, but also implies when SPNC is applied in multi-antenna relay, TWRC can be viewed as an effective single-input multiple-output (SIMO) system, in which AS-PNC and SC-PNC are equivalent to the general AS scheme and the maximal-ratio combining (MRC) scheme. Moreover, an asymptotic analysis of symbol error rate (SER) is provided for SC-PNC considering the case that the number of relay antennas is sufficiently large
On Outage Probability and Diversity-Multiplexing Tradeoff in MIMO Relay Channels
Fading MIMO relay channels are studied analytically, when the source and
destination are equipped with multiple antennas and the relays have a single
one. Compact closed-form expressions are obtained for the outage probability
under i.i.d. and correlated Rayleigh-fading links. Low-outage approximations
are derived, which reveal a number of insights, including the impact of
correlation, of the number of antennas, of relay noise and of relaying
protocol. The effect of correlation is shown to be negligible, unless the
channel becomes almost fully correlated. The SNR loss of relay fading channels
compared to the AWGN channel is quantified. The SNR-asymptotic
diversity-multiplexing tradeoff (DMT) is obtained for a broad class of fading
distributions, including, as special cases, Rayleigh, Rice, Nakagami, Weibull,
which may be non-identical, spatially correlated and/or non-zero mean. The DMT
is shown to depend not on a particular fading distribution, but rather on its
polynomial behavior near zero, and is the same for the simple
"amplify-and-forward" protocol and more complicated "decode-and-forward" one
with capacity achieving codes, i.e. the full processing capability at the relay
does not help to improve the DMT. There is however a significant difference
between the SNR-asymptotic DMT and the finite-SNR outage performance: while the
former is not improved by using an extra antenna on either side, the latter can
be significantly improved and, in particular, an extra antenna can be
traded-off for a full processing capability at the relay. The results are
extended to the multi-relay channels with selection relaying and typical outage
events are identified.Comment: accepted by IEEE Trans. on Comm., 201
Secrecy performance of TAS/SC-based multi-hop harvest-to-transmit cognitive WSNs under joint constraint of interference and hardware imperfection
In this paper, we evaluate the secrecy performance of multi-hop cognitive wireless sensor networks (WSNs). In the secondary network, a source transmits its data to a destination via the multi-hop relaying model using the transmit antenna selection (TAS)/selection combining (SC) technique at each hop, in the presence of an eavesdropper who wants to receive the data illegally. The secondary transmitters, including the source and intermediate relays, have to harvest energy from radio-frequency signals of a power beacon for transmitting the source data. Moreover, their transmit power must be adjusted to satisfy the quality of service (QoS) of the primary network. Under the joint impact of hardware imperfection and interference constraint, expressions for the transmit power for the secondary transmitters are derived. We also derive exact and asymptotic expressions of secrecy outage probability (SOP) and probability of non-zero secrecy capacity (PNSC) for the proposed protocol over Rayleigh fading channel. The derivations are then verified by Monte Carlo simulations.Web of Science195art. no. 116
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