Reproducible LTE uplink performance analysis using precomputed interference signals

Abstract The consideration of realistic uplink inter-cell interference is essential for the overall performance testing of future cellular systems, and in particular for the evaluation of the radio resource management (RRM) algorithms. Most beyond-3G communication systems employ orthogonal multiple access in uplink (SC-FDMA in LTE and OFDMA in WiMAX), and additionally rely on frequency-selective RRM (scheduling) algorithms. This makes the task of accurate modeling of uplink interference both crucial and non-trivial. Traditional methods for its modeling (e.g., via additive white Gaussian noise interference sources) are therefore proving to be ineffective to realistically model the uplink interference in the next generation cellular systems. In this article, we propose the use of realistic precomputed interference patterns for LTE uplink performance analysis and testing. The interference patterns are generated via an LTE system-level simulator for a given set of scenario parameters, such as cell configuration, user configurations, and traffic models. The generated interference patterns (some of which are made publicly available) can be employed to benchmark the performance of any LTE uplink system in both lab simulations and field trials for practical deployments. It is worth mentioning that the proposed approach can also be extended to other cellular communication systems employing OFDMA-like multiple access with frequency-selective RRM techniques. The proposed approach offers twofold advantages. First, it allows for repeatability and reproducibility of the performance analysis. This is of crucial significance not only for researchers and developers to analyze the behavior and performance of their systems, but also for the network operators to compare the performance of competing system vendors. Second, the proposed testing mechanism evades the need for deployment of multiple cells (with multiple active users in each) to achieve realistic field trials, thereby resulting in significant cost (and time) savings in the field trails.</p

Interference coordination-based downlink scheduling for heterogeneous LTE-A networks

We propose a novel scheduler for an LTE-A network, which dynamically coordinates inter-cell interference for vulnerable users while limiting the effort of coordination. Vulnerable users are identified first, and then protected by assigning resources exclusively to them. Inter-cell interference coordination (ICIC) messages are transmitted to neighboring base stations (eNodeBs) via the X2 interface using LTE-Typical constraints. The proposed scheduler and ICIC methods are compliant with the LTE and LTE-A standards. Closed-loop spatial multiplexing is used. The proposed scheduler is evaluated in a 2-Tier heterogeneous network (HetNet). In comparison with the benchmark schedulers, simulation results for vulnerable users show a substantial gain in terms of throughput. In addition, the proposed scheduler guarantees a minimum data rate for a longer time

Partial interference cancellation in heterogeneous LTE-advanced networks

In LTE networks, picocells are deployed to take over load from macrocells in areas of high user density or weak coverage. Their support comes at the cost of severe intercell interference if single frequency reuse is implemented. In this paper, a cooperative interference mitigation scheme is presented that combines the theoretical work on rate splitting of Han and Kobayashi with the transmission of MIMO-layers as it is defined in LTE. Two users from different cells form a cooperating pair. A cell-edge user detects a part of the interference such that the effective interference is decreased. Thus, it can be served at a higher data rate. This work focuses on an asymmetric scenario in which a cell-edge user and a cell-center user of neighboring cells form a cooperating pair. Simulations show that the cell-edge user can significantly improve its spectral efficiency compared to treating the whole interference as noise with only small losses for the cell-center user. The proposed scheme uses the tools available in LTE and adds only little overhead for the cooperation

QoS-aware traffic scheduling in LTE-advanced relay-enhanced networks

The main challenge when providing quality of services in future mobile networks is the low signal quality regimes, mainly experienced by the users located at the cell edge. The deployment of relay nodes promises significant improvement of the received signal quality and enables the establishment of QoS-aware services for such users. In this work, we propose and study the performance of a novel QoS-aware scheduling algorithm focusing on LTE-Advanced relay-enhanced networks. Using traffic with different QoS requirements for the downlink stream, we demonstrate that the proposed QoS-aware scheduling algorithm efficiently serve traffic with mixed rate and delay requirements. Moreover, it manages to maintain a reasonable service quality for all the users including the relayed users. We finalize this work comparing the performance of the proposed scheme to a reference scheduler. © 2013 IEEE

EU FP7 INFSO-ICT-247223 ARTIST4G, D3.4 Relay configurations

The following document contains proposals for innovations on relay configurations made by partners involved in the Artist4G project WP3, Task 3.3. The different relay configurations are for in-band and out-band relays, multi-hop relays, and moving relays. For each innovation, a description, the potential deviation from a defined baseline architecture, and simulation results (as far as available) are included. Important issues regarding the innovations impact on the architecture are pointed out and analysed in detail. This analysis will also be forwarded to WP4

EU FP7 INFSO-ICT-247223 ARTIST4G, D3.4 Relay configurations

The following document contains proposals for innovations on relay configurations made by partners involved in the Artist4G project WP3, Task 3.3. The different relay configurations are for in-band and out-band relays, multi-hop relays, and moving relays. For each innovation, a description, the potential deviation from a defined baseline architecture, and simulation results (as far as available) are included. Important issues regarding the innovations impact on the architecture are pointed out and analysed in detail. This analysis will also be forwarded to WP4

EU FP7 INFSO-ICT-247223 ARTIST4G, D3.1 Definitions and Architecture requirements for supporting Advanced Relay concepts

The following document addresses the questions received from WP4 and presents the architecture requirements and targets that need to be considered by WP4 in order to support advanced relays in future wireless networks