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We present a theoretical model of amplified spontaneous emission noise in few-mode fiber Raman amplifiers. Under the undepleted-pump approximation, equalization of modal gain also ensures equalization of OSNR. This modal allows the prediction of mode-dependent OSNRs in the saturated-pump regime. The experimental results are in good agreement with theoretical estimations.
We consider the resource allocation and beamforming design for system utility maximization in a cloud radio access network (C-RAN) under given fronthaul rate constraints and quality of service (QoS) requirements at users. The considered problem is known to be NP-hard and thus it is difficult to obtain global optimum solutions. Under practical assumptions, we approximate the considered problem using...
In this paper, we consider the power splitting technique for multiple-input single-output (MISO) interference channel where the received signal is divided into two parts for information decoding and energy harvesting (EH) respectively. Specifically, assuming norm-bounded errors (NBE) in the channel state information (CSI), we study the robust joint beamforming and power splitting (JBPS) design problem,...
We consider the admission control of small cell access points (SAPs) supported by wireless backhaul in a heterogeneous network. The SAP admission control in wireless backhaul is performed at the wireless backhaul hub (WBH), which aims to serve as many SAPs as possible with the guaranteed data rates. Such a problem involves joint design of transmit beamformers, power control, and selection of SAPs,...
We investigate a carrier frequency offset (CFO) estimation algorithm for coherent optical quaternary phase-shift keying (QPSK) receivers. The algorithm utilizes the phase difference between the samples with different time-domain separations, so that the estimation accuracy can be significantly enhanced, compared with the algorithm that only compares the phase difference between adjacent samples. In...
Offset quadrature amplitude modulation (offset-QAM) orthogonal frequency division multiplexing (OFDM) can greatly relax the needs of guard interval (GI) for longdistance optical transmission. In this paper, we show that 40-Gbit/s offset-16QAM OFDM can support 840-km transmission with negligible performance penalty when GI is not applied. In contrast, a GI length of 12 samples is required in conventional...
We address uplink user admission control problems in multiuser wireless systems with multiple single-antenna users and a multi-antenna receiver. Our aim is to select the maximum number of users that can simultaneously satisfy the given quality of service (QoS) and power constraints from a large number of candidates in the system. Both sum and per-user transmit power constraints are considered. By...
Joint transmission (JT) is an attractive coordinated multipoint (CoMP) downlink transmission technique in multi-cell networks. It offers high system throughput but needs to distribute each user data to multiple base stations (BSs), which can lead to huge backhaul signaling overhead when the number of users is large. In this paper, we address the problem of jointly optimizing the BS assignment for...
Coordinated multipoint (CoMP) transmission has been proposed as an important strategy to improve the signal quality for cell-edge users in future mobile cellular standards. However, when the joint transmission technique is applied in the CoMP downlink, the user data transferred from the data center to the base stations (BSs) can lead to a huge backhaul signaling overhead. Subject to quality-of-service...
We propose blind maximum-likelihood carrier frequency offset (CFO) estimation for coherent fast OFDM receivers. Simulation results show that the estimation algorithm can greatly enhance the CFO tolerance, and is insensitive to chromatic dispersion.
When the joint processing technique is applied in the coordinated multipoint (CoMP) transmission downlink, the user data for each mobile station (MS) needs to be distributed among multiple base stations (BSs), which incurs the exchange of user data via the backhaul. In order to alleviate the requirement on the backhaul capacity, we propose to minimize the exchange of user data among the BSs, subject...
We demonstrate that digital back-propagation offers up to six-fold enhancement in transmission reach when nonlinear fibre impairments are compensated in coherently-detected 112 Gb/s PM m-ary QAM, with greater enhancement for higher order formats.
We propose a novel transmission scheme for the broadcast phase of two-way relaying systems. The proposed scheme employs network coding at the relay and is able to transmit with asymmetric data rates to the receivers according to their individual link qualities. The idea is that the weaker link receiver exploits a priori bit information in each transmit symbol, so that it only needs to decode on a...
Optical performance monitoring is an important function for high capacity optical transmission system. In this paper, we summarize some of the recent work we have carried out in this area. In particular, PMD independent OSNR monitoring, OSNR monitoring using half symbol delay for SNR monitoring of RZ-DQPSK signal and signed residue dispersion monitoring of CSRZ-DQPSK signal using delay tap sampling...
We analyzed 10 GHz NRZ-DPSK signals' PM-AM conversion process and demonstrated chromatic dispersion (CD) and OSNR monitoring simultaneously based on measuring 010 GHz RF spectrum power of the PRBS signals. The monitoring range of CD and OSNR are up to 4320 ps/nm and 10-30 dB respectively.
Multi-chip joint maximum likelihood sequence estimation (MLSE) is proposed and shown to outperform joint MLSE, achieving 330 km optically-uncompensated 10 GS/s DQPSK signal transmission and less than 3 dB OSNR penalty for 100 ps DGD.
We demonstrate DPSK signal dispersion monitoring by measuring low frequency RF power. This scheme can realize dispersion monitoring up to 4320 ps/nm with sensitivity to 0.045 dBm/ps/nm. OSNR effect on the monitoring system is studied and discussed.
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