3,562 research outputs found
On the Achievable Rates of Decentralized Equalization in Massive MU-MIMO Systems
Massive multi-user (MU) multiple-input multiple-output (MIMO) promises
significant gains in spectral efficiency compared to traditional, small-scale
MIMO technology. Linear equalization algorithms, such as zero forcing (ZF) or
minimum mean-square error (MMSE)-based methods, typically rely on centralized
processing at the base station (BS), which results in (i) excessively high
interconnect and chip input/output data rates, and (ii) high computational
complexity. In this paper, we investigate the achievable rates of decentralized
equalization that mitigates both of these issues. We consider two distinct BS
architectures that partition the antenna array into clusters, each associated
with independent radio-frequency chains and signal processing hardware, and the
results of each cluster are fused in a feedforward network. For both
architectures, we consider ZF, MMSE, and a novel, non-linear equalization
algorithm that builds upon approximate message passing (AMP), and we
theoretically analyze the achievable rates of these methods. Our results
demonstrate that decentralized equalization with our AMP-based methods incurs
no or only a negligible loss in terms of achievable rates compared to that of
centralized solutions.Comment: Will be presented at the 2017 IEEE International Symposium on
Information Theor
VLSI Architectures and Rapid Prototyping Testbeds for Wireless Systems
The rapid evolution of wireless access is creating an ever changing variety of standards for indoor and outdoor environments. The real-time processing demands of wireless data rates in excess of 100 Mbps is a challenging problem for
architecture design and verification. In this paper, we consider current trends in VLSI architecture and in rapid prototyping testbeds to evaluate these systems. The key phases in multi-standard system design and prototyping
include: Algorithm Mapping to Parallel Architectures – based on the real-time data and sampling rate and the resulting area, time and power complexity; Configurable Mappings and Design Exploration – based on heterogeneous architectures consisting of DSP, programmable application-specific instruction (ASIP) processors, and co-processors; and Verification and Testbed Integration
– based on prototype implementation on programmable devices and integration with RF units.Nokia Foundation FellowshipNokia CorporationNational InstrumentsNational Science Foundatio
Large-Scale MIMO Detection for 3GPP LTE: Algorithms and FPGA Implementations
Large-scale (or massive) multiple-input multiple-output (MIMO) is expected to
be one of the key technologies in next-generation multi-user cellular systems,
based on the upcoming 3GPP LTE Release 12 standard, for example. In this work,
we propose - to the best of our knowledge - the first VLSI design enabling
high-throughput data detection in single-carrier frequency-division multiple
access (SC-FDMA)-based large-scale MIMO systems. We propose a new approximate
matrix inversion algorithm relying on a Neumann series expansion, which
substantially reduces the complexity of linear data detection. We analyze the
associated error, and we compare its performance and complexity to those of an
exact linear detector. We present corresponding VLSI architectures, which
perform exact and approximate soft-output detection for large-scale MIMO
systems with various antenna/user configurations. Reference implementation
results for a Xilinx Virtex-7 XC7VX980T FPGA show that our designs are able to
achieve more than 600 Mb/s for a 128 antenna, 8 user 3GPP LTE-based large-scale
MIMO system. We finally provide a performance/complexity trade-off comparison
using the presented FPGA designs, which reveals that the detector circuit of
choice is determined by the ratio between BS antennas and users, as well as the
desired error-rate performance.Comment: To appear in the IEEE Journal of Selected Topics in Signal Processin
LOW-COMPLEXITY AND HIGH-PERFORMANCE SOFT MIMO DETECTION BASED ON DISTRIBUTED M-ALGORITHM THROUGH TRELLIS-DIAGRAM
This paper presents a novel low-complexity multiple-input multipleoutput (MIMO) detection scheme using a distributed M-algorithm (DM) to achieve high performance soft MIMO detection. To reduce the searching complexity, we build a MIMO trellis graph and split the searching operations among different nodes, where each node will apply the M-algorithm. Instead of keeping a global candidate list as the traditional detector does, this algorithm keeps multiple small candidate lists to generate soft information. Since the DM algorithm can achieve good BER performance with a small M, the sorting cost of the DM algorithm is lower than that of the conventional K-best MIMO algorithm. The proposed algorithm is very suitable for high speed parallel processing.NokiaNokia Siemens Networks (NSN)XilinxNational Science Foundatio
Scalable Architecture of MIMO Multi-carrier CDMA System on Programmable Logic
In this paper, a scalable architecture of the multicarrier CDMA system using Multiple-Input-Multiple-Output (MIMO) technology is designed in the programmable logic array. The system-level partitioning with different architecture
design entries is described. The overall computing architecture for complex signal processing blocks, e.g., channel estimation, frequency domain equalization, demodulation etc is described. The MIMO architecture is easily extended from a SISO system with single antenna. This scalable architecture demonstrates resource utilization efficiency and easy extension to MIMO
configurations
Distributed Decoding in Cooperative Communications
In this paper, we present a novel relaying strategy called distributed and partial decoding. This strategy can be viewed as a variation of the decode and forward with the difference that the relay partially decodes the signal, re-transmits it to the destination, and the destination continues the decoding.
By distributing the decoding process between the relay and the destination, the relay uses less processing power and less time. This is very suitable for practical applications in which relays are battery-operated (such as handsets) and do not want to use all their battery power on relaying the data of other users.Nokia CorporationNational Science Foundatio
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