... Accession Number : ADA543383. Title : On the Performance of Serially Concatenated CPM-OFDMA Schemes for Aeronautical Telemetry. ...

A novel long-reach, hybrid wavelength-division multiplexing (WDM) and time-division multiplexing (TDM) passive optical network (PON) architecture which supports local area network (LAN) emulation among customers is proposed. Orthogonal frequency division multiplexing access (OFDMA) technology is used in optical network units (ONUs) to transmit the LAN ...

Wideband code division multiple access (WCDMA) is currently being extended into high-speed downlink access (HSDPA) and high-speed uplink packet access (HSUPA). The continuing research of next generation communication proposed by 3GPP is named long term evolution (LTE). The main goal of LTE Release is to offer high peak downlink and ...

The integration of multihop relays with orthogonal frequency-division multiple access (OFDMA) cellular infrastructures can meet the growing demands for better coverage and higher throughput. Resource allocation in the OFDMA two-hop relay system is more complex than that in the conventional single-hop ...

Some OFDMA-based wireless commuication systems, e. g., Wireless Broadband Internet (WiBro) or Worldwide interoperability for Microwave Access (WiMAX), support frequency reuse of 1 to maximize spectral efficiency. One of the efficient methods to reduce co-channel interference (CCI) caused by frequency reuse is fractional frequency reuse ...

The dynamic channel allocation (DCA) scheme in multi-cell systems causes serious inter-cell interference (ICI) problem to some existing calls when channels for new calls are allocated. Such a problem can be addressed by advanced centralized DCA design that is able to minimize ICI. Thus, in this paper, a centralized DCA is developed for the downlink of multi-cell orthogonal ...

This paper considers the weighted sum rate (WSR) maximized resource allocation (RA) constrained by a system sum power in an orthogonal frequency division multiple access (OFDMA) downlink transmission system assisted by multiple decode-and-forward (DF) relays. In particular, multiple relays may cooperate with the ...

. Cendrillon, W. Yu, M. Moonen, J. Verlinden, and T. Bostoen, "Optimal multiuser spectrum balancing for digital

to interference (SIR) ratio and cellular capacity. Analytical models are proposed for integer frequency reuse (IFR. Keywords OFDMA, Fluid Model, SINR, IFR, FFR 1. INTRODUCTION Orthogonal frequency division multiple access reuse (IFR) reuse 1 cellular network (cf. section 3 for an introduction on IFR). The CCI becomes more

To mitigate the asynchronous ICI (Inter-Cell Interference), SCM (Spatial Covariance Matrix) of the asynchronous ICI plus background noise should be accurately estimated for MIMO-OFDMA (Multiple-input Multiple-output-Orthogonal Frequency Division Multiple Access) system. Generally, it is assumed that the SCM of the asynchronous ICI plus ...

In this letter, we propose an efficient resource allocation scheme that improves the system performance by reducing the signaling overhead for voice over Internet protocol (VoIP) services in the IEEE 802.16e OFDMA system. We theoretically analyze the performance of the proposed allocation scheme and carry out a computer simulation to ...

LTE Systemoptimierung durch dynamische OFDMA Methoden unter Ber�cksichtung des PDCCH Signalisierungskanals ITG Fachgruppe 5.2.1 - Workshop LTE / WiMAX Mathias Bohge Jena, 09.05.2008 #12;LTE System Optimization constraint to dynamic assignment signalling reliability ITG Fachgruppe 5.2.1 - Workshop LTE / Wi

In this letter, we propose an adaptive transmission method for an OFDMA system supporting both band-AMC and diversity modes in a frame, simultaneously. In the proposed method, users are classified into the two groups preferring the band-AMC mode or the diversity mode based on their channel parameters. Then the BS performs resource allocation to maximize ...

In this paper, we consider a two-hop relay-assisted cognitive downlink OFDMA system (named as secondary system) dynamically accessing a spectrum licensed to a primary network, thereby improving the efficiency of spectrum usage. A cluster-based relay-assisted architecture is proposed for the secondary ...

We have proposed and experimentally demonstrated a 60-GHz bidirectional radio-over-fiber system with downstream orthogonal frequency division multiplexing address (OFDMA) and wavelength reuse upstream single-carrier frequency division multiple address (SC-FDMA). In the downstream, a 3-dB optical coupler is used for two-carrier injection-locking a ...

-- Opportunistic Spectrum Access (OSA) is being seriously considered for the future spectrum needs. In this paper we propose a simple and effective multichannel multiple access technique for OSA networks. In our design users of an OSA network must contact the OSA Base Station to gain access to the radio resources

Multi-cell resource allocation under minimum rate request for each user in OFDMA networks is addressed in this paper. Based on Lagrange dual decomposition theory, the joint multi-cell resource allocation problem is decomposed and modeled as a limited-cooperative game, and a distributed multi-cell resource allocation algorithm is thus proposed. Analysis and simulation results ...

/s exchange OFDM / OFDMA for Fixed Radio Access NT network termination ONT optical network termination OFDMAfor OFDM Adaptive Frequency Domain Equalization Ralph Hasholzner Institute for Integrated Circuits � OFDM - basics � fixed radio access scenario and channel models part 2: adaptive frequency domain

Orthogonal Frequency Division Multiple Access (OFDMA) is the technique for the next generation wireless networks, whose enhanced capacity is to serve a combination of traffic with diverse QoS requirements. To realize this, the resource allocation scheme has to be carefully designed so that the instantaneous channel condition, QoS provision, and the network ...

, in the context of 3GPP LTE, called hereafter -LTE, sustain our theoretical claims. I. INTRODUCTION is then extended to the multi-user OFDMA (Mul- tiple Access OFDM) case, where 3GPP-Long Term Evolution (LTE) is used as benchmark comparison. Although both - LTE and LTE with frequency hopping techniques seem

Abstract�After the IEEE 802.16-2004 standard was published, much attention was drawn to providing broadband access in rural and developing areas over fixed wireless channels. Now, the IEEE 802.16e standard for Mobile WiMAX is about to be published. It is known that Mobile WiMAX will incorporate error-correction capability and will be an enhanced version of the IEEE 802.16 ...

In this letter, the effect of the time difference of arrival (TDoA) on synchronous types or asynchronous types of OFDMA-based multi-hop relay (MR) systems is investigated. Signal-to-interference plus noise ratios (SINRs) for downlinks and uplinks are defined to measure the degree of interference due to TDoA in asymmetric MR systems. A ...

Adaptive vs. Diversity Transmission for Multiuser MISO Systems with Imperfect CSIT Frederick K and diversity schemes for a multiuser multiple- input single-output (MISO) system. Comparative performance-input single- output (MISO) OFDMA system. The base station uses mul- tiple transmit antennas, but each user has

This paper introduces a new pilot pattern design for channel estimation in WiMAX. Current WiMAX systems use a subcarrier allocation technique known as Uplink Partial Usage of Subcarriers (UL-PUSC). It is based on tile structure that consists of 4 subcarriers by 3 OFDMA symbols with 4 pilots in the corners to aid the channel estimation process. We propose a ...

) is referred to as the Alternating-Projection Frequency Estimator (APFE). C. Initialization of the CFOs. In the following, the estimator based on the approximation Eq. (18) is called the Approximate APFE (AAPFE). F of the frequency estimates vs. SNR as obtained with APFE and AAPFE. It turns out that the performance of APFE

by the International Telecommunication Union (ITU) for IMT2000 technology as OFDMA-time-division duplex (TDD as beamforming (BF) features. The release 1.0 system profile is defined only for the TDD mode of operation based on ven- dors and testing tool availability. The early phas- es of certification were also limited

Sensing of OFDMA systems for cognitive radio networks", IEEE Trans. Vehicular technolgy, Vol. 58, Issue 7 Technolgy Conf., May 2004, Vol. 2, pp. 1172-1176. [16] T. Banerjee, V. Kavitha and V. Sharma, "Energy

In wireless LANs, different multi-user access methods such as TDMA, OFDMA and SDMA are available which can be used with or without channel knowledge at the transmitter and a single antenna (MISO) or multiple antennas (MIMO) at the receiver. A cross-layer scheduler is considered which can be configured with these different PHY methods as well as with ...

In this paper, a novel decentralised dynamic sub-carrier assignment (DSA) algorithm for orthogonal frequency division multiple access (OFDMA)-based adhoc and cellular networks operating in time division duplexing (TDD) mode is proposed to solve the hidden and exposed node problem in media access control (MAC). This method reduces the ...

WiMAX system is based on OFDMA, and it is very suitable for VoIP traffic. At the same time, aggressive AMC and frame bundling are two important techniques to improve the performance of VoIP, and so they are applied to WiMAX system in this paper. The simulation results show that when the system is in short of ...

System spectral efficiency and user fairness are crucial aspects for resource allocation in multi-user OFDM-based cellular networks. This work intends to investigate the influence of the performance of packet scheduling algorithms on the trade-off between these two objectives in scenarios with non real-time and real-time services. By means of system-level ...

We have developed a novel downlink packet scheduling scheme for a multiuser OFDMA system in which a subchannel can be time-multiplexed among multiple users. This scheme which is called Matrixed-based Proportional Fairness can provide a high system throughput while ensuring fairness. The scheme is based on a Proportional Fairness (PF) ...