10 research outputs found
Improving Generalized Spatial Modulation using Translation Patterns
Generalized spatial modulation (GSM) is a spectral-efficient technique used
in multiple-input multiple-output (MIMO) wireless communications when the
number of radio frequency chains at the transmitter is less than the number of
transmit antenna elements. We propose a family of signal constellations, as an
improvement over GSM, which splits the information bits into three parts, and
encodes the first part into a set of complex symbols, the second part into the
choice of a subset of antennas activated for transmission (as in GSM), and the
third into a translation pattern that offsets the symbols transmitted through
the activated antennas. The nominal coding gain (the ratio of the squared
minimum distance between transmit vectors to the transmit power) of our scheme
is higher than that of GSM by at least 0.86 dB, and this improvement can be as
much as 2.87 dB based on the system parameters. We show that the new scheme has
advantages over other known signal constellations for GSM, in terms of error
performance, nominal coding gain and design flexibility.Comment: Accepted for publication in the IEEE Communications Letters.
Keywords: coding gain, generalized spatial modulation (GSM), MIMO, minimum
distanc
Spatial Scattering Modulation with Multipath Component Aggregation Based on Antenna Arrays
In this paper, a multipath component aggregation (MCA) mechanism is
introduced for spatial scattering modulation (SSM) to overcome the limitation
in conventional SSM that the transmit antenna array steers the beam to a single
multipath (MP) component at each instance. In the proposed MCA-SSM system,
information bits are divided into two streams. One is mapped to an
amplitude-phase-modulation (APM) constellation symbol, and the other is mapped
to a beam vector symbol which steers multiple beams to selected strongest MP
components via an MCA matrix. In comparison with the conventional SSM system,
the proposed MCA-SSM enhances the bit error performance by avoiding both low
receiving power due to steering the beam to a single weak MP component and
inter-MP interference due to MP components with close values of angle of
arrival (AoA) or angle of departure (AoD). For the proposed MCA-SSM, a union
upper bound (UUB) on the average bit error probability (ABEP) with any MCA
matrix is analytically derived and validated via Monte Carlo simulations. Based
on the UUB, the MCA matrix is analytically optimized to minimize the ABEP of
the MCA-SSM. Finally, numerical experiments are carried out, which show that
the proposed MCA-SSM system remarkably outperforms the state-of-the-art SSM
system in terms of ABEP under a typical indoor environment
Enhanced Huffman Coded OFDM with Index Modulation
In this paper, we propose an enhanced Huffman coded orthogonal
frequency-division multiplexing with index modulation (EHC-OFDM-IM) scheme. The
proposed scheme is capable of utilizing all legitimate subcarrier activation
patterns (SAPs) and adapting the bijective mapping relation between SAPs and
leaves on a given Huffman tree according to channel state information (CSI). As
a result, a dynamic codebook update mechanism is obtained, which can provide
more reliable transmissions. We take the average block error rate (BLER) as the
performance evaluation metric and approximate it in closed form when the
transmit power allocated to each subcarrier is independent of channel states.
Also, we propose two CSI-based power allocation schemes with different
requirements for computational complexity to further improve the error
performance. Subsequently, we carry out numerical simulations to corroborate
the error performance analysis and the proposed dynamic power allocation
schemes. By studying the numerical results, we find that the depth of the
Huffman tree has a significant impact on the error performance when the
SAP-to-leaf mapping relation is optimized based on CSI. Meanwhile, through
numerical results, we also discuss the trade-off between error performance and
data transmission rate and investigate the impacts of imperfect CSI on the
error performance of EHC-OFDM-IM
Quadrature spatial modulation aided single-input multiple-output-media based modulation: application to cooperative network and golden code orthogonal super-symbol systems.
Doctoral Degree. University of KwaZulu-Natal, Durban.SIMO-MBM (single-input multiple-output media-based modulation) overcomes the limitations of SIMO (single-input multiple-output) systems by reducing the number of antennas required to achieve a high data rate and improved error performance. In this thesis, the quadrature dimension of the spatial constellation is used to improve the overall error performance of the conventional SIMO-MBM and to achieve a higher data rate by decomposing the amplitude/phase modulation (APM) symbol into real and imaginary components, similar to quadrature spatial modulation (QSM).
The average bit error probability of the proposed technique is expressed using a lower bound approach and validated using the results of Monte Carlo simulation (MCS). The proposed system also investigates the effect of antenna correlation in combination with channel amplitude to select a sub-optimal mirror activation pattern. The results of MCS show a 3.5dB improvement at 10b/s/Hz with m =2 and a 7dB improvement at 12b/s/Hz with =2 over the traditional SIMO-MBM scheme. The effect of imperfect channel estimation on the proposed scheme is investigated, with a trade-off of 2dB in coding gain due to channel estimation errors.
Cooperative Networking (CN) improves wireless network reliability, link quality, and spectrum efficiency by collaborating among nodes. The decode and forward relaying technique is used in this thesis to investigate the performance of QSM aided SIMO-MBM in a Cooperative Network (CN). This technique uses two source nodes that simultaneously transmit a unique message block on the same time slot to the relay node, which then decodes the received message block from both transmitting nodes before re-encoding and re-transmitting the decoded message block in the next time slot to the destinations in order to significantly improve the QSM aided SIMO-MBM’s error performance.
Using network coding (NC) techniques, each Node can decode the data of the other Node. To enhance network performance, complexity, robustness, and minimize delays, data is encoded and decoded in NC; algebraic techniques are applied to the detected message to collect the various transmissions. The proposed scheme's theoretical average error probability was defined using a lower bound technique, and the results of Monte Carlo simulation (MCS) validated the result. The MCS results achieved exhibit a significant improvement of 8 dB at 6 b/s/Hz and 12 dB at 8 b/s/Hz over the conventional QSM aided SIMO-MBM scheme.
The media-based modulation (MBM) technique can achieve significant throughput, increase spectrum efficiency, and improve bit-error-rate performance (BER). In this thesis, the use of MBM in single-input multiple-output systems is examined using radio frequency (RF) mirrors and Golden code (GC-SIMO). The goal is to lower the system's hardware complexity by maximizing the linear relationship between RF mirrors and spectral efficiency in MBM in order to achieve a high data rate with less hardware complexity. The GC scheme's encoder uses orthogonal pairs of the super-symbol, each transmitted via a separate RF mirror at a different time slot to achieve full rate full diversity.
In the results of MCS obtained, at a BER of 10−5, the GC-SIMO-MBM exhibits a significant performance of approximately 7dB and 6.5 dB SNR gain for 4 b/s/Hz and 6 b/s/Hz, respectively, compared to GC-SIMO. The proposed scheme's derived theoretical average error probability is validated by the results of the Monte Carlo simulation