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An Algorithm for Constructing All Families of Codes of Arbitrary Requirement in an OCDMA System
White Papers Compared with traditional bandwidth-shared methods such as Time Division Multiplexing (TDM) and Wavelength Division Multiplexing (WDM) systems, OCDMA has many advantages such as high security and capacity potential.
[June 16, 2006, 1:00]
Traffic Engineering and Quality of Service in Cisco IP/MPLS Mobile Backbones for Enhanced Network Performance, Service Reliability and Manageability
White Papers IP/MPLS can be used by mobile operators as a common backbone for gradually replacing their traditional ATM, Frame Relay, and Time-Division Multiplexing (TDM) networks. This paper describes the IP/MPLS traffic engineering and QoS capabilities in...
[January 31, 2009, 4:37]
Orthogonal Frequency Division Multiplexing Based on Offset QAM
White Papers One of the factors determining the performance of wireless Orthogonal Frequency Division Multiplexing (OFDM) systems is time-frequency localization of the transmitter and receiver pulse shaping filters.
[March 28, 2005, 0:00]
Techniques for Suppression of Intercarrier Interference in OFDM Systems
White Papers This paper considers an orthogonal frequency division multiplexing (OFDM) system over frequency selective time-varying fading channels. The time variations of the channel during one OFDM frame destroy the orthogonality of different subcarriers and...
[July 21, 2005, 6:00]
Iterative Interference Cancellation and Channel Estimation for Mobile OFDM
White Papers In mobile reception, the reliability of Orthogonal Frequency Division Multiplexing (OFDM) is limited because of the time-varying nature of the channel. This causes InterCarrier Interference (ICI) and increases inaccuracies in channel tracking.
[August 31, 2009, 1:22]
Wireless Virtualization on Commodity 802.11 Hardware
White Papers Among different possible wireless virtualization strategies, the current work in this domain is focussed on a Time-Division Multiplexing (TDM) approach. The wireless virtualization system is specifically targeted for multiplexing experiments on a...
[March 1, 2008, 0:02]
IP Telephony Case Study: How Cisco IT Merged Voice and Data Engineering Groups
White Papers Telecommunications focused on Time-Division Multiplexing (TDM)-based Private Branch Exchange (PBX) switches. When Cisco Systems migrated to IP communications, previously separate networking and voice networks converged, along with their respective...
[March 5, 2008, 0:02]
Cisco IP Contact Center Solutions to Be Deployed by Cox Communications
White Papers Because the company is currently using traditional Time Division Multiplexing (TDM) technology, each contact center is dependent upon individual Automatic Call Distribution (ACD), Computer-Telephony Integration (CTI) and Interactive Voice Response...
[June 7, 2006, 0:00]
Modified SMI Techniques for Frequency Selective Channels in OFDM
White Papers In this paper, windowing techniques are applied in order to calculate a beamformer per subcarrier for Orthogonal Frequency Division Multiplexing (OFDM) systems with very limited known training. However, in Time Division Multiple Access (TDMA...
[April 14, 2007, 1:01]
Transmit Diversity Vs Beamforming for Multi-User OFDM Systems
White Papers In an Orthogonal Frequency Division Multiplexing (OFDM) system, downlink beamforming can be implemented either before IDFT (frequency domain) or after IDFT (time domain) module in a base station transmitter.
[April 18, 2007, 1:00]
Differential Modulation Diversity for OFDM
White Papers The application of Differential Modulation Diversity (DMD) to orthogonal frequency division multiplexing with multiple transmit and/or receive antennas is considered. Based on diagonal signals originally designed for differential space-time...
[April 14, 2007, 1:01]
Adaptive Channel SVD Estimation for MIMO-OFDM Systems
White Papers In this paper an adaptive estimation algorithm for channel matrix singular value decomposition (SVD) in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed.
[July 21, 2005, 6:00]
On Cyclic Delay Diversity in OFDM Based Transmission Schemes
White Papers Cyclic Delay Diversity (CDD) is a simple approach to introduce spatial diversity to an Orthogonal Frequency Division Multiplexing (OFDM) based transmission scheme that itself has no built-in diversity.
[March 25, 2008, 7:41]
Blind and Semiblind Spatio-Temporal Diversity for OFDM Systems
White Papers Adaptive antenna arrays can be used to improve the performance of Orthogonal Frequency Division Multiplexing systems. In this paper, the selected algorithms are applied in time domain. They are usually applied in the frequency domain, after the FFT...
[April 14, 2007, 1:01]
Traffic Engineering and Quality of Service in Cisco IP/MPLS Mobile Backbones for Enhanced Network Performance, Service Reliability, and Manageability
White Papers IP/MPLS can be used by mobile operators as a common backbone for gradually replacing their traditional ATM, Frame Relay, and Time-Division Multiplexing (TDM) networks. Moving toward third-generation (3G) mobile network standards and satisfying...
[October 1, 2008, 1:01]
Voice Quality: Deploying Tools for a Stable Infrastructure
White Papers The shift from the traditional Time-Division Multiplexing (TDM) world to a packet-based IP telephony solution poses challenges for voice quality. This paper provides insight into voice quality and the different methods to measure voice quality.
[June 13, 2008, 1:01]
Broadband MIMO-OFDM Wireless Communications
White Papers Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and/or to enhance the system...
[November 2, 2004, 2:00]
Performance Degradation of OFDM Systems Due to Doppler Spreading
White Papers The focus of this paper is on the performance of Orthogonal Frequency Division Multiplexing (OFDM) signals in mobile radio applications, such as 802.11a and Digital Video Broadcasting (DVB) systems, e.g.
[April 11, 2007, 1:01]
Analysis of the Impact of WiMAX-OFDM Interference on Multiband OFDM
White Papers This paper presents an analysis of the performance of the Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) system for Ultra WideBand (UWB) communication in the presence of interference from an IEEE 802.16 WiMAXOFDM system operating...
[April 23, 2009, 1:24]
Exploiting Time Diversity to Improve Block Spread OFDM
White Papers A method used to implement mutually orthogonal signals is called Orthogonal Frequency Division Multiplexing (OFDM) and this is done by setting up multiple carriers at a suitable frequency separation and modulating each symbol stream separately.
[April 11, 2007, 1:01]
