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Downlink Multicell MIMO-OFDM: An Architecture for Next Generation Wireless Networks
White Papers This paper considers a multicell MIMO-OFDM TDD system where the emphasis is on the downlink for future data-intensive applications. Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier transmission scheme that is well-recognized for...
[July 26, 2005, 0:00]
Downlink Performance and Capacity of Distributed Antenna Systems in a Multicell Environment
White Papers This paper analytically quantifies the performance of downlink multicell DAS in terms of power efficiency, SINR improvement, and outage probability for two different transmission strategies: selection diversity (where just one or two of the...
[October 11, 2005, 3:00]
Downlink Scheduling and Resource Allocation for OFDM Systems
White Papers This paper considers scheduling and resource allocation for the downlink of a OFDM-based wireless network. During each time-slot the scheduling and resource allocation problem involves selecting a subset of users for transmission, determining the...
[April 13, 2007, 1:01]
WiMAX Downlink OFDMA Burst Placement for Optimized Receiver Duty-Cycling
White Papers In this standard, a strict organization of the downlink bursts is not guaranteed in the OFDMA frame and this may lead to extra power consumption for the receiver, decreasing the device's lifetime. Mobile wireless broadband access networks are now...
[April 22, 2009, 1:24]
High Speed Downlink Packet Access (HSDPA): Higher Data Rates for UMTS
White Papers High Speed Downlink Packet Access is the first step in the evolution of WCDMA (UMTS) networks. The second step will be to enhance the uplink data rates, improved uplink capacity and reduced uplink delay.
[March 23, 2005, 2:00]
HSDPA (High Speed Downlink Packet Access): A Simplistic View of HSDPA Architecture and Its Applications
White Papers High Speed Downlink Packet Access (HSDPA) is the new technology which is introduced in 3GPP Release 5. As the name suggests, HSDPA will enable the user to achieve high data rates in the downlink while on the move.
[September 1, 2006, 0:00]
Capacity Analysis on Downlink MIMO OFDMA Systems
White Papers This paper shows that in terms of total system capacity, OFDMA is the optimal downlink scheme for independent decoding receivers. Motivated by the increasing popularity of OFDMA and MIMO, this paper studies the capacity of MIMO enabled OFDMA system...
[November 2, 2004, 2:00]
Joint Uplink and Downlink Capacity Considerations in Admission Control in Multiservice CDMA/HSDPA Systems
White Papers In the latter case, packets are typically found in the downlink whereas ACKs are in the uplink. Those two links are asymmetric in the case of CDMA-based High Data Rate (HDR)/High-Speed Downlink Packet Access (HSDPA) systems, the uplink being much...
[December 21, 2007, 0:01]
Efficient MIMO Equalization for Downlink Multi-Code CDMA: Complexity Optimization and Comparative Study
White Papers This paper presents an efficient LMMSE chip equalizer to suppress the interference caused by the multipath fading channel in the MIMO Multi-Code CDMA downlink. The block-Toeplitz structure in the correlation matrix is approximated with a block...
[August 26, 2009, 1:20]
An Efficient Circulant MIMO Equalizer for CDMA Downlink: Algorithm and VLSI Architecture
White Papers This paper presents an efficient circulant approximation based MIMO equalizer architecture for the CDMA downlink. Wireless communication is experiencing radical advancement to support broadband multimedia services and ubiquitous networking via...
[October 6, 2005, 3:00]
Performance of a Low-Complexity Downlink Channel Estimator for Long-Code CDMA Systems
White Papers Recently, a blind downlink channel estimator is proposed for long-code CDMA systems based on a covariance matching idea. By modeling long spreading codes as random codes and pre-computing some code-dependent quantities, the algorithm shows...
[November 8, 2006, 0:00]
Temporal Diversity Assisted Blind Channel Estimation for Downlink Long-Code CDMA Systems
White Papers In CDMA downlink, subspace channel estimation can not be applied directly since long spreading codes destroy the rank condition of the received data covariance matrix. However, after introducing temporal diversity in the transmitted chip sequence...
[November 8, 2006, 0:00]
Performance of Channel Estimation Assisted Linear Multiuser Receivers for Downlink CDMA Systems With Long Spreading Codes
White Papers With availability of spatial/temporal diversity in the downlink of long code CDMA systems, subspace technique has been shown to be able to estimate channel parameters. Based on the estimated channel, the authors construct three typical linear...
[November 8, 2006, 0:00]
Subspace-Based Channel Estimation for CDMA Downlink With Aperiodic Spreading Codes and Multiple Subchannels
White Papers This paper considers a downlink CDMA system with aperiodic spreading codes and multipath propagation. Assisted by either multiple antennas or oversampling, multiple subchannels are created. Then subspace technique can be directly applied to...
[November 8, 2006, 0:00]
Downlink Radio Resource Allocation for Multi-Cell OFDMA System
White Papers Orthogonal frequency division multiple access (OFDMA) provides a feasible broadband platform where different forms of multiuser diversities (e.g.mutual interference, selective fading channels and bursty traffics) can be efficiently exploited.
[November 2, 2004, 2:00]
Fast Broadcasting
White Papers Broadcast transmission, as proposed by Cover, is an optimal downlink transmission method to serve many users by a single base station. Substituting or complementing the fast scheduler in high speed downlink schemes, broadcasting schemes should have...
[April 11, 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]
Vodafone mobile broadband to hit top HSDPA speed
News The move makes Vodafone the first British operator to roll out the highest specification for high-speed downlink packet access (HSDPA). According to Vodafone, most of the customers connecting to base stations that offer 14.4Mbps will get somewhere...
[August 27, 2009, 14:12]
UK leads Europe in satellite broadband
News Two types are available -- two-way, which provides both a fast uplink and a fast downlink, and one-way, where a user gets a fast downlink but must upload information much more slowly, via a telephone line.
[June 4, 2003, 12:51]
Be pushes upstream broadband past 2Mbps
News Be said it would upgrade its Office ADSL2+ service - which offers a downlink of up to 22Mbps - to support these faster uplink speeds later this year. This was shortly before it began promoting its DSL Max product, due to launch later this month...
[March 15, 2006, 16:15]
