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The current convergence process in wireless technologies demands for strong efforts in the conceiving of highly flexible and interoperable equipments. This contribution focuses on one of the most important baseband processing units in wireless receivers, the forward error correction unit, and proposes a Network-on-Chip (NoC) based approach to the design of multi-standard decoders. High level modeling...
Deploying FemtoCells in WiMAX network, also called WiMAX FemtoCell architecture, gains a lot of attention due to better indoor services can be provided and WiMAX network traffic can be shared by the FemtoCell. However, since the signal of WiMAX base station (BS) is stronger than FemtoCell Base Station (fBS), the handover procedure may not be triggered even though fBS is within the BS coverage. Besides,...
Low-density parity-check (LDPC) codes are widely used in many radio systems due to its superior performance and Software Defined Radio (SDR) is an emerging paradigm of the wireless communication system design due to its good flexibility and adaptability. However, LDPC decoding is computationally intensive and the implementation of it on software in a parallel way is quite challenging due to the characteristics...
In order to address the large variety of channel coding options specified in existing and future digital communication standards, there is an increasing need for flexible solutions. This paper presents a multi-core architecture which supports convolutional codes, binary/duo-binary turbo codes, and LDPC codes. The proposed architecture is based on Application Specific Instruction-set Processors (ASIP)...
An adaptive rate controller (ARC) based on adaptive neural fuzzy inference system (ANFIS) is designed to autonomously adjust the data rate of a mobile heterogeneous network to adapt the changing traffic load and the user speed for multimedia call services. Through simulations, it is demonstrated that the ARC is able to maintain new call blocking probability and handoff failure probability of the mobile...
A power/area aware design is mandatory for the MIMO (Multi-Input Multi-Output) detectors used in LTE and WiMAX standards. The 64-QAM modulation used in the MIMO detector requires more detection effort compared to the smaller constellation sizes widely implemented in the literature. In this work we propose a new architecture for the K-best detector, which unlike the popular multi-stage architecture...
A novel coordinated scheduling algorithm for OFDM-based systems in multi-cell scenario is proposed in this paper. The studied algorithm based on the utility function is general for the downlink of networks. The algorithm coordinates the subcarrier assignment over the BS cluster. We first establish the framework for this inter-cell coordinated optimization problem through utility-based method. The...
The current literature lacks the VLSI realization of high-order multiple-input-multiple-output (MIMO) detectors in the complex domain, which finds applications in advanced wireless standards such as WiMAX and Long Term Evolution (LTE) systems. In this paper, a novel modified complex K-Best algorithm and its VLSI implementation for a 4 × 4, 64QAM complex MIMO detector are proposed. The main contributions...
In this paper, we present a novel 128/256-point FFT/ IFFT processor for the applications in IEEE 802.16e based on MIMO-OFDM. The pipeline FFT architecture is proposed to efficiently deal with 1-4 multiple data sequences, and increase the throughput. Furthermore, less hardware complexity is needed in our design compared with conventional individual parallel approach. The signal-to-quantization noise...
This paper presents a VLSI architecture of a novel soft-output K-Best MIMO detector. The proposed detector attains low computational complexity using three improvement ideas: relevant discarded paths selection, last stage on-demand expansion, and relaxed LLR computation. A deeply pipelined architecture for a soft-output MIMO detector is implemented for a 4×4 64-QAM MIMO system realizing a peak throughput...
WiMax mobile cellular systems are envisioned to provide high data rate multimedia service to users at any time, anywhere at an affordable cost. WiMax is operated at a frequency higher than 2 GHz because of the intensive usage of the frequency bands below and around 2 GHz by the current 2 G, 3 G and other systems. At fixed transmission power, both high data rate and high frequency indicate smaller...
MIMO wireless technology is required to increase the data rates for a broad range of applications, including low cost mobile devices. In this paper we present a very low area reconfigurable MIMO detector which achieves a high throughput of 103Mbps and uses 27 Kilo Gates when implemented in a commercial 180nm CMOS process. The low area is achieved by the proposed in-place architecture. This architecture...
This paper represents high speed and high throughput pipelined Fast Fourier Transform and its inverse (FFT/IFFT) for Mobile Wi-MAX. Modified architecture also provides concept of local ROM module and variable length support from 128~2048 point for FFT/IFFT. UMC 0.18 ??m is used to design the same. FFT/IFFT chip consumes 266.81 mW at 40 MHz, 130.74 mW at 20 MHz and 65 mW at 10 MHz for length of 2048...
Turbo codes are widely used in many radio systems due to its superior performance and Software Radio (SR) is an emerging paradigm of the wireless communication system design due to its good flexibility and adaptability. However, since turbo decoding is computationally intensive, the SR implementation of turbo decoding is always challenging. In this paper, an efficient software implementation of the...
In this paper, we propose a ??sleep mode restriction?? scheme for improving the effective cell throughput of worldwide interoperability for microwave access (WiMAX) systems when a mobile station (MS) switches its serving network from WLAN to WiMAX in heterogeneous networks. In the previous scheme, a MS acquires the information related to vertical handover (VHO) from media independent handover (MIH)...
High-end embedded wireless communication applications demand high performance, strict low power, and in-field reprogrammability to follow the evolving standards. Today's single-core GPPs or DSPs cannot satisfy the challenging market performance requirements. Through specially tailoring individual processor core architectures to best fit a set of dedicated applications, heterogeneous multi-core architectures...
Future wireless communication systems are expected to provide more stable and higher data rate transmissions in the whole network. WiMAX is one of the technologies to cover diverse geographic regions. WiMAX covers the high dense urban areas and provide access over large geographic regions in remote rural area. However, in both scenarios it is challenging to cover the entire service area. In both cases...
A new Dynamic Resource Allocator (DRA) architecture, based on a cross-layer framework, by using the control and signal channels implemented in the IEEE802.16e standard, is proposed. Commonly and a new designed packet schedulers are used in the performance evaluation of the DRA, by means of system level simulations under a realistic network layout, conducted on a proprietary C++ platform, fully compatible...
MIMO systems (with multiple transmit and receive antennas) are becoming increasingly popular, and many next-generation systems such as WiMAX, 3-GPP LTE and IEEE802.11n wireless LANs relay on the increased throughput of MIMO systems with up to four antennas at receiver and transmitter. High throughput implementation of the detection unit for MIMO systems is a significant challenge especially for higher...
In this paper we propose a novel totally WiMAX-based architecture for large scale wireless broadband access. To provision scalable QoS, nodes' traffic should be managed locally. This is achieved through adding some gateway nodes which consequently leads to some cost. In order to realize the proposed architecture, intelligent node placement is primordial such the both cost and performance requirements...
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