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Power control has been extensively studied as an important way of mitigating interference and providing minimum signal to interference plus noise ratio (SINR) guarantees. Such formulation of power control is well-motivated in cellular PCS and UMTS, as both voice and streaming media require guaranteed short-term rates. A key difficulty is that the problem can easily become infeasible, implying that...
This paper presents an efficient method for calculating the Precoding Matrix Indicator (PMI), Rank Indicator (RI) and Channel Quality Indicator (CQI) at a Long Term Evolution (LTE) User Equipment (UE). The indicators are required for spatial preprocessing and link adaption in the downlink of a 3GPP UMTS/LTE system. To reduce the computational burden for the UE, our method decomposes the problem into...
This paper presents a comparison between CDMA and SC-FDMA for reverse link (RL) cellular voice and data communications. The comparison is based on CDMA2000 1x (circuit-switched voice), CDMA2000 1xEV-DO (packet data) and 3GPP LTE Release 8 (SC-FDMA based packet voice and data). We illustrate various modes of LTE system operation and associated trade-offs. For the comparison of data communications we...
This paper evaluates the performance of highly loaded High Speed Uplink Packet Access (HSUPA) network with and without network wide static Interference Coordination (IC). IC alternates the priorities for user transmission periods throughout the network to achieve reduced interference levels and higher performance. A large variety of combinations including, e.g., different schedulers, cell center/edge...
In this paper, a novel interference coordination scheme based on Dynamic Resource Allocation (DRA) for mitigating inter-cell interference in Long Term Evolution (LTE) cellular systems is presented. In both OFDMA and SC-FDMA systems, inter-cell interference is the most important interference source. Inter-cell interference coordination is considered to improve coverage and increase date rate at cell...
In this paper, we deal with user scheduling algorithms for a codebook based precoding of a multiuser multiple-input multiple-output (MIMO) downlink system considered in IEEE 802.16m and 3rd Generation Partnership Project Long-Term Evolution (3GPP LTE) standardization. We especially focus on per-user unitary rate control (PU2RC) and semi-orthogonal user selection schemes. Also, we examine the disadvantage...
The architecture for the Beyond 3rd Generation or 4th Generation wireless networks aims at integrating various heterogeneous wireless access networks over an IP backbone. To provide seamless mobility, one of the design issues is the vertical handoff support. In this paper, we propose a SINR (Signal to Interference plus Noise Ratio) and AHP (Analytic Hierarchy Process) based SAW (Simple Additive Weighting)(SASAW)...
This paper presents a novel spatial frequency domain packet scheduling and frequency domain equalization (FDE) algorithm for uplink Single Carrier (SC) Frequency Division Multiple Access (FDMA) multiuser MIMO systems. Our analysis model is confined to 3GPP uplink SC-FDMA transmission with Multi-user (MU) Spatial Division Multiplexing (SDM). The results show that the proposed MU-MIMO scheduler in conjunction...
We consider the downlink of an Orthogonal Frequency Division Multiple Access (OFDMA) network. OFDMA transmission technology will be used in the next generation of wireless networks such as the LTE (Long Term Evolution) and WiMAX wireless standards. In such a channel, multiple User Equipments (UE) may each be allocated multiple Resource Blocks (RBs) in each frame. A RB is a collection of subcarriers...
Relays can be used between the source and the destination to improve network coverage or reliability. In the relay based distributed space-time block-coded (DSTBC) single-carrier (SC) transmission scheme, asynchronism in time and frequency causes degradation in system performance because of the interblock interference, non-coherent combining and multiuser interference. The simultaneous presence of...
Commercial HSDPA measurements are used in order to derive an approach for the location based orthogonality factor. It is found that the orthogonality factor is correlated with the difference between the free space path loss and the measured path loss. A path loss difference close to 0 dB indicates line of sight and the maximal orthogonality factor is reached. With increasing path loss difference the...
The interference situation in the uplink of cellular networks, such as the 3GPP UTRAN Long Term Evolution (LTE), is usually highly volatile since from one transmission time interval to the other different users might be scheduled in nearby cells, thus often causing completely different levels of interference. This unstable behavior of the interference generally has a negative impact on the performance...
This paper shows how statistical properties of the downlink interference vary along a fractional network loading in case of the 3GPP Long Term Evolution (LTE) system in highly interference limited scenario, where radio resources are shared in time and frequency domain with proportional fair (PF) scheduler. Results show at least 15 dB variations in average signal-to-interference (SINR) ratios for scheduled...
Higher Order Modulation (HOM, 64-QAM) and Multiple Input Multiple Output (MIMO) transmissions are two key features introduced in the Release 7 (HSPA+) WCDMA systems to improve downlink performance. This paper focuses on the performance analysis of 64-QAM and MIMO in the WCDMA system. We describe the equalizer design for supporting these features as well as the simulation results demonstrating the...
We evaluate the performance of the uplink of a 3GPP UTRAN Long Term Evolution (LTE) system with intra-site cooperation, where different sectors belonging to the same site may cooperate with each other in order to improve the system performance. This represents an intermediate step towards general coordinated multipoint (CoMP) systems as currently under discussion for LTE-Advanced, where a cooperation...
Coordinated Multi-Point transmission and reception (CoMP) technique has been adopted in LTE-Advanced as one of the promising techniques because it can significantly increase the throughput of the cell edge user and the total sector throughput for both downlink and uplink transmission. Compared with conventional cellular system, CoMP can reduce inter-cell interference (ICI) significantly. On the other...
This paper studies the different ways of extending wireless coverage for high data rates and improving the data capacity in a building. The solutions considered include deployments of single or multiple small base stations, i.e. Picocell or Femtocell, and distributed antenna system, operated on the same frequency as the macro cellular network. We look at the radio performance of each solution in a...
The Time Division Duplex (TDD) uplink-downlink configuration of the 3GPP Long Term Evolution (LTE) determines how the ten subframes in a radio frame are divided between the downlink and the uplink. The specified configurations cover a wide range of allocations from a downlink-heavy resource distribution ratio (9:1) to an uplink-heavy ratio (2:3). In this paper, we compare the performance of Internet...
3rd Generation Partnership Project (3GPP) responsible of the standardization of 3G systems selected dual stream Transmit Antenna Array (D-TxAA) as the Multiple Input - Multiple Output (MIMO) scheme for High Speed Downlink Packet Access (HSDPA) in 3GPP specification Release 7. MIMO doubles the theoretical peak data rate of HSDPA from 14.4 Mbps to 28.8 Mbps. However, successful reception of dual stream...
We investigate enhanced downlink multiuser multiple input multiple output (MU-MIMO) transmission schemes for 3GPP LTE-Advanced based on system level simulations. As compared to Rel. 8 LTE single user MIMO (SU-MIMO), MU-MIMO has the potential to better exploit the spatial dimension of MIMO channels in some scenarios. Although Rel. 8 LTE defines a simple MU-MIMO mode, more advanced MU-MIMO techniques...
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