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This paper presents results from a novel OFDMA multi-cell mobile broadband system level simulator. The tool is used to statistically characterize uplink and downlink inter-cell interference. Without suitable interference management, multi-billion dollar networks can collapse under the strain of heavy traffic loads. Fully loaded interference studies cannot be performed on the network until it has been...
The performance evaluation of the MIMO transmission schemes based on the IEEE 802.16m technology by the system level simulation is conducted in this paper. IEEE 802.16m technology supports various MIMO transmission schemes. We perform the evaluation of the system by applying various MIMO transmission schemes and compare the results. The evaluation results for each channel can be indicator to select...
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...
Coordinated multipoint or cooperative MIMO is one of the promising concepts to improve cell edge user data rate and spectral efficiency beyond what is possible with MIMOOFDM in the first versions of LTE or WiMAX. Interference can be exploited or mitigated by cooperation between sectors or different sites. Significant gains can be shown for both the uplink and downlink. A range of technical challenges...
In this paper, we propose a bit and power allocation strategy for adaptive modulation and coding (AMC) based spatial multiplexing multi-input-multi-output (MIMO) orthogonal frequency division multiple access (OFDMA) systems. This strategy aims to maximize the average system throughput by allocating the available resources optimally among the utilized bands depending on the corresponding channel conditions...
In this paper, mobile WiMAX trials are analysed to investigate the vehicular down-link performance for a number of on-car antenna configurations. The directionality and optimum polarization of the vehicular antennas are shown to improve both the range and throughput of the system. These improvements are attributed to the additional directive gain, and the reduced multi-input multi-output spatial correlation...
Smart Antenna Systems use the additional degrees of freedom offered by their multiple antennas to exploit, among other things, multipath in the propagation environment. Therefore, by construction, antenna design of smart antenna systems cannot be assessed by simple performance metrics such as gain, polarization and efficiency alone. At a minimum, performance has to be considered in the context of...
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...
In this paper, a low-complexity symbol detector is presented targeting the emerging 3GPP LTE and WiMAX standards. The detector is the VLSI implementation of a novel MIMO detection algorithm recently proposed. Compared to the design in the reference, the detector performs better while consumes less silicon area. Including a microcode controlled channel preprocessing unit and a pipelined detection unit,...
This contribution provides insight into the performance of the currently deployed 3G cellular systems HSDPA and WiMAX. In extensive measurement campaigns we measured the physical layer throughput of these 3G systems in different environments (alpine and urban) and compare the results rigorously to their upper bounds derived from the well known Shannon capacity. By separating the observed losses into...
We present an algorithm and architecture of a soft-output sphere decoder with an optimized hardware implementation for 2??2 MIMO-OFDM reception. We introduce a novel table look-up approach for symbol enumeration that simplifies the implementation of soft-output decoders. The HW implementation is targeted towards WLAN (IEEE 802.11n) with stringent latency and throughput requirements. The current implementation...
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...
In this work, we present physical layer throughput measurement results of a WiMAX link implemented according to IEEE 802.16-2004. The measurements were carried out in an alpine and an urban scenario using the Vienna MIMO Testbed. We compare the measured throughput to three different theoretical bounds: 1) the channel capacity, 2) the mutual information, and 3) a so-called ??achievable throughput??...
Modern wireless communication systems employ MIMO and feedback-two properties that make it especially difficult to measure the performance of such systems with reasonable effort in actual outdoor scenarios. In this paper, we will present a time, cost, and manpower efficient measurement approach to evaluate the throughput achieved by such systems. Summer/winter, large distance outdoor-toindoor/outdoor,...
In this paper, we propose a radio resource allocation (RRA) scheme for multiuser multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing access (OFDMA) systems in order to achieve the optimal system throughput. The proposed RRA algorithm adaptively schedules 3-dimension (3-D) (space, frequency and time) slots to different users according to various channel state information...
The WiMAX standard has emerged to harmonise the wide variety of broadband wireless access (BWA) technologies. The recent mobile WiMAX standard (802.16e) supports broadband applications to mobile terminals and laptops in urban environments. Mobile WiMAX supports a full range of multiple-input multiple-output (MIMO) techniques including space time block coding (STBC), spatial multiplexing (SM) and eigen-beamforming...
In this paper, we evaluate the system-level performance of MIMO-based Mobile WiMAX system, a.k.a. Wave-2 system, especially taking the spatially correlated channel characteristics and channel estimation error into account in the different radio environments and propagation scenarios. Our simulation framework carefully follows the standard evaluation methodology and channel models, especially provided...
In this paper, gains of the codebook based CL-MIMO for down link WiMax system has been studied using system level simulations. The system level simulation is based on the IEEE 802.16 m evaluation methodology. The 2 times 2 and 4 times 2 antenna configurations, and 3 bits and 6 bits preferred matrix index (PMI) feedback codebooks are considered. Both the sub-band and wide band PMI feedback are studied...
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