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An Energy Efficient Subcarrier-power Allocation scheme for Polarization-Amplitude-Phase Modulation in channel with Polarization Mode Dispersion
Abstract
An Energy Efficient Subcarrier-power Allocation (EESA) scheme is proposed to improve the Power Amplifier (PA) energy efficiency. The proposed scheme is applied for the Polarization-Amplitude-Phase Modulation (PAPM) in the channel with Polarization Mode Dispersion (PMD). Considering a multiuser downlink system, utilizing the diversity of the polarization characteristic on each subcarrier caused by PMD, EESA scheme can make PA energy efficiency optimal under the constraint of each user terminal's data demand. To reduce the allocation's computationally complexity, the EESA scheme performs the subcarrier allocation and power allocation separately. Firstly, by assuming the equal power distribution, the subcarrier is allocated through Differential Evolution (DE); then based the obtained subcarrier allocation method, a two-step allocation algorithm is presented to distribute the PA input power on each subcarrier. Through numerical calculation, the optimal parameters setting of DE is examined. Our results show that the EESA scheme is able to achieve significant improvement in PA energy efficiency.
... In wireless communication, the polarization modulation (PM) is a novel modulation technique to improve the performance, such as BER [28] and energy efficiency [29][30][31][32]. Moreover, it has been found in [33] that the polarization state (PS) of the signal is insensitive to phase noise. ...
... We have proposed the differential polarization shift keying, which is a special PM, to cancel phase noise for the OFDM system in our prior work [34]. In a realistic wireless channel, the polarized signals are distorted by depolarization, such as cross-polarization discrimination (XPD) [35,36], polarization-dependent loss (PDL), and polarization mode dispersion (PMD) [37]; some papers propose the channel compensation methods to improve the PM performance [29][30][31][32][38][39][40]. In this paper, we extend the phase noise cancelation scheme for a larger number of antenna scenarios under XPD effect. ...
... Based on the additive noise after ZF detection which is subject to Gaussian distribution, the phase noise effect on the desired signal can be canceled. According to (28) and (32), the multiplicative phase noises in (23) can be transformed to additive aŝ ...
In massive multiple-input multiple-output (MIMO) systems, phase noise introduced by oscillators can cause severe performance loss. It leads to common phase error and intercarrier interference in massive MIMO-OFDM uplink. To solve the issue, a novel phase noise cancelation scheme based on polarization modulation for the massive MIMO-OFDM system is proposed. We first introduce the polarization modulation (PM) exploited in massive MIMO-OFDM uplink. Then, by exploiting the zero-forcing detection, we analyze the asymptotically ICI and the distribution of the transformed noise under different XPD values. Furthermore, we demonstrate that phase noise can be asymptotically canceled and only the transformed additive white Gaussian noise exists as the number of antennas at the base station is very large. Moreover, we derive the instantaneous signal-to-noise ratio (SNR) on each subcarrier and analyze the ergodic capacity. To increase the ergodic capacity performance further, a joint modulation scheme combining the PM and 2PSK is proposed and the ergodic capacity performance of the joint modulation is discussed. The simulation results show that the proposed scheme can effectively mitigate phase noise and achieve a higher ergodic capacity.
... With the development of polarization theory, many scholars are motivated by PolSK modulation, and apply the polarization states to carry information, called Polarization Modulation (PM). For example, Wei Dong [6]- [9] proposed PAM (Polarization Amplitude Modulation) modulation, which combines polarization modulation with traditional modulation to improve the system power efficiency.Ruomeng Li [10] propose a continuous polarization modulation method to improve the spectral efficiency. Polarization modulation is mainly used in terrestrial wireless communication at the initial stage. ...
... In (5), U and V are unitary matrices and produce a rigid rotation effect on the constellation, which means that both the constellation structure of PM and power remain unchanged. But ∑ lead to the constellation constriction and the constellation distance decreases, which means that the unbalanced power would cause the structural distortion called polarizationdependent loss (PDL) [9]. The measurement can be defined as P DL = 10 log (λ 1 /λ 2 ). ...
... Since the two transmit signals allocate the same transmission power, the value of λ 1 and λ 2 is very closed [12]. Wei D in [9] used the pre-compensation to miiitigate the PDL effect. Therefore, AWGN is considered as main affection of PM in satellite communications. ...
... In performance analyses, the energy efficiency of the proposed scheme is compared with phase shift keying (PSK) modulation and significant reduction in energy consumption is observed. Wei et al. [23] aim for an energy-efficient subcarrierpower allocation (EESA) scheme. EESA is implemented for the polarization-amplitude-phase modulation (PAPM) in the channel with polarization mode dispersion (PMD). ...
The reduction of energy consumption has become a key research area for the information and communication technology (ICT) industry, due to economical, environmental, and marketing reasons. While the environmental direction aims at minimization of greenhouse gas emissions by enforcing the usage of renewable energy in the ICT industry, economical and marketing directions lead researchers to design low-power components or develop and enhance energy-saving protocols without an impact on the level of the performance. With the steady increase in the cost of energy, the expanding number of energy-hungry components and widespread usage of ICT industry, most of the protocols that have become an integral part of our lives but are yet developed without any energy constraints in mind in the past will need to be restructured or developed again. For this reason, researchers are studying on all layers of the Internet protocol stack to develop energy-efficient protocols and algorithms. This paper reviews recent approaches for energy efficiency studies for each layer in the Internet protocol stack from the physical layer to the application layer. It is expected that with the deployment of current research output, the studies performed at each layer will result in significant energy savings for the ICT industry which in turn will have a positive impact on our lives for their economical and environmental results.
Polarization is an important property of electromagnetic waves. It has shown the great application potential in optical fiber, radar, and satellite communications, where polarization has been exploited to be a promising means of enhancing channel capacity. The existing research has shown that, in theory, it has great potential to sixfold the channel capacity by using six co-located orthogonally polarized electric and magnetic dipoles. Wireless communications exploits the electromagnetic medium, which is also intrinsically polarization-sensitive. In the past decades, wireless communications have mainly exploited the dimensions of time, frequency, and space, and most wireless channels, technologies, and applications have been devised without explicit consideration of polarization. To keep up with the recent exponentially growing network capacity, as such, leveraging polarization for wireless communications is a logical next step. However, exploiting polarization in wireless communications involves many challenges that differentiate it from conventional polarization applications in terms of optical fiber, radar, and satellite communications due to complex depolarization effects, restriction on additional gain offered, and limited degrees of freedom in the polarization domain. These challenges have inspired recent advances, particularly related to polarization channels, polarization technologies (such as polarization-based modulation, polarization-based signal sensing, polarization-based orthogonal transmission, and polarization-based filtering), and their applications to emerging communication scenarios including energy-efficient communications, cognitive radio networks, and in-band full-duplex transmission. This paper thoroughly surveys these recent advances and presents the state-of-the-art research progress on each aspect. Furthermore, open research issues and challenges are discussed in order to provide perspectives for future research directions.
To adapt to variation of polarization dependent loss (PDL) in depolarization channel, an adaptive polarization modulation scheme which can improve the spectral efficiency of polarization modulation system is proposed. In the proposed scheme, the transmitter adapts the optimal constellation size to the variation of the channel due to PDL while fulfilling a fixed target BER constraint, which is based on the received feedback information of channel state information estimated at the receiver. Our simulation results and analysis show that, adaptive polarization modulation (APM) can achieve higher spectral efficiency (SE) than nonadaptive polarization modulation, subject to the same fixed target BER constraint.
Mobile communications are increasingly contributing to global energy consumption. In this article, a holistic approach for energy efficient mobile radio networks is presented. The matter of having appropriate metrics and evaluation methods that allow assessing the energy efficiency of the entire system is discussed. The mutual supplementary saving concepts comprise component, link and network levels. At the component level the power amplifier complemented by a transceiver and a digital platform supporting advanced power management are key to efficient radio implementations. Discontinuous transmission by base stations, where hardware components are switched off, facilitate energy efficient operation at the link level. At the network level, the potential for reducing energy consumption is in the layout of networks and their management, that take into account slowly changing daily load patterns, as well as highly dynamic traffic fluctuations. Moreover, research has to analyze new disruptive architectural approaches, including multi-hop transmission, ad-hoc meshed networks, terminal-to-terminal communications, and cooperative multipoint architectures.
Differential Evolution (DE) is a simple but powerful evolutionary optimization algorithm with many successful applications.
In this paper we propose Differential Evolution for Multiobjective Optimization (DEMO) – a new approach to multiobjective
optimization based on DE. DEMO combines the advantages of DE with the mechanisms of Pareto-based ranking and crowding distance
sorting, used by state-of-the-art evolutionary algorithms for multiobjective optimization. DEMO is implemented in three variants
that achieve competitive results on five ZDT test problems.
Multiuser orthogonal frequency division multiplexing (MU-OFDM) is a promising technique for achieving high downlink capacities in future cellular and wireless local area network (LAN) systems. The sum capacity of MU-OFDM is maximized when each subchannel is assigned to the user with the best channel-to-noise ratio for that subchannel, with power subsequently distributed by water-filling. However, fairness among the users cannot generally be achieved with such a scheme. In this paper, a set of proportional fairness constraints is imposed to assure that each user can achieve a required data rate, as in a system with quality of service guarantees. Since the optimal solution to the constrained fairness problem is extremely computationally complex to obtain, a low-complexity suboptimal algorithm that separates subchannel allocation and power allocation is proposed. In the proposed algorithm, subchannel allocation is first performed by assuming an equal power distribution. An optimal power allocation algorithm then maximizes the sum capacity while maintaining proportional fairness. The proposed algorithm is shown to achieve about 95% of the optimal capacity in a two-user system, while reducing the complexity from exponential to linear in the number of subchannels. It is also shown that with the proposed resource allocation algorithm, the sum capacity is distributed more fairly and flexibly among users than the sum capacity maximization method.
To improve the Power Amplifier (PA) energy efficiency, a Polarization Modulation (PM) scheme that uses the Polarization State (PS) as the information bearing parameter is proposed. Since the PS determined by orthogonally dual-polarized antennas is unaffected by PA, PM can let PA operate in nonlinear region without suffering the distortion. Furthermore, to mitigate the wireless channel depolarization impairment to PM from the polarization dependent loss and the polarization mode dispersion, an Optimal Constellation Pre-compensation (OCP) algorithm is also presented. The simulation results show, with same symbol error rate, PM can reduce the energy consumption per bit by 25% at most compared with the traditional multi-phase shift keying.
To improve the power amplifier (PA) energy efficiency, a polarization–amplitude–phase modulation (PAPM) scheme in wireless communication is proposed. The proposed scheme introduces the signal’s polarization state (PS), amplitude, and phase as the information-bearing parameters. Thus, the data rate can be further enhanced on the basis of the traditional amplitude–phase modulation. Also, since the transmitted signal’s PS completely manipulated by orthogonally dual-polarized antennas is unaffected by PA, PAPM can let PA work in its nonlinear region to acquire high PA efficiency. To further optimize the PA energy efficiency based on PAPM, a constrained optimization problem regarding the output back-off value and the ratio between the data carried by the PS and the amplitude–phase is formulated, and the distribution of the optimum solutions is presented. The simulation results show that PAPM can improve the PA energy efficiency significantly.
We assess the selection of strategy parameters for Differential Evolution on a set of test problems. The original algorithm is analyzed with respect to its performance depending on the choice of strategy parameters. Although empirical rules are provided in the literature [1], choosing the proper strategy parameters for Differential Evolution is more difficult than expected.
A 2times2 multiple-input multiple-output (MIMO) architecture using dual-polarized antennas (DPAs) is considered with orthogonal frequency division multiplexing (OFDM). The performance of DPAs is evaluated for adaptive polarization (AP) transmission techniques in time-varying multipath channels impaired by polarization mode dispersion (PMD) and polarization-dependent loss (PDL). AP transmission techniques considered include power gain maximization, polarization dispersion minimization for interference avoidance, polarization multiplexing with water-filling, and a suboptimal multiplexing strategy that enables direct recovery of the polarization multiplexed streams, thereby simplifying the design of the receiver. Measured time-varying dual-polarized channel realizations from mobile-to-mobile experiments are used to estimate the capacity, diversity, and interference avoidance performance of the adaptive approaches.
This paper presents a theoretical characterization of nonlinear distortion effects in orthogonal frequency division multiplexing (OFDM) transmission systems. In the theoretical framework developed, it is shown that the effects on the decision variables of the in-band distortion introduced by a bandpass memoryless nonlinearity can be described by means of a complex gain and an additive Gaussian term with zero mean and suitable variance; analytical expressions for gain and variance are given. The conditions which allow this description are emphasized and discussed. As a consequence, a completely analytical procedure to evaluate error probability is also obtained and illustrated using OFDM/discrete multitone modulation (DMT) systems with rectangular pulse shaping; for the soft-envelope limiter nonlinearity, a closed form is derived. A comparison with simulation results is carried out to verify the accuracy of this method.
Multilevel digital coherent optical modulation schemes based on
the state of polarization of a fully polarized lightwave are proposed
and analyzed. Based on the complete statistical characterization of the
Stokes parameters, extracted through appropriate signal processing in
the presence of shot and additive Gaussian noise, the optimum maximum
likelihood receiver operating symbol by symbol is derived. The exact
performance in terms of the average symbol error probability is found.
Optimum constellations for the case of equipower 4, 8, 16 and 32 signals
are found on the basis of the minimization of the error probability for
a given average power. Their performance turns out to be promising as
compared to other standard modulation techniques. The spectral analysis
of polarization modulated signals is presented. A new receiver
structure, which solves the problem of the excess penalties incurred in
the presence of channel dichroism, is proposed and analyzed
Radar Polarization Information Processing and Application
- Zhaowen Zhuang
- Shunping Xiao
- Xuesong Wang