Israel Guío

Downlink scheduling for intercell interference fluctuation mitigation in partial-loaded broadband cellular OFDMA systems

In this paper, we analyze the problem of strong intercell interference (ICI) fluctuations in OFDMA networks with frequency reuse of one and their effects on system performance. Our goal is to outperform fractional frequency reuse scheme by proposing a joint time and frequency resource scheduling algorithm that limits ICI fluctuations both in full and partially loaded scenarios. Adaptive MCS selection according to channel conditions in addition to traffic requirements is considered. Simulation results show that our proposed scheme enhances the system performance and the user satisfaction.

Interference Management through Resource Allocation in Multi-Cell OFDMA Networks

This work addresses the problem of inter-cell interference (ICI) management in the context of single frequency broadband OFDMA-based networks. Five proposals, based on a combination of ICI coordination/avoidance techniques along with a set of heuristic adaptive power and subcarrier allocation algorithms, have been considered in order to achieve better interference performance and resource utilization in a multi-cellular environment. Connected with a proper power mask based design, the potential gain of a flexible frequency sectorization solution, halfway between fractional/soft frequency reuse and pure frequency sectorization, is explored.

Radio resource strategies for uplink inter-cell interference fluctuation reduction in SC-FDMA cellular systems

In this paper we propose three different frequency resource management strategies that, working together with FFR and open-loop Fractional Power Control (PFC), succeed on mitigating both uplink inter-cell interference (ICI) and ICI fluctuations, that usually reduce the performance of SC-FDMA cell-based systems. Simulations are carried out with real-time traffic patterns at different loading scenarios, showing that our strategies outperform a typical FFR scheme suggested to coordinate frequency assignments among neighboring cells.

Inter-Cell Interference Management in SC-FDMA Cellular Systems

In this paper we study the performance of a SC-FDMA cellular system when a complete Inter-Cell Interference (ICI) management strategy is implemented. We also introduce a novel sector-and-zone frequency ICI coordination scheme, derived from Fractional Frequency Reuse (FFR), which succeeds on increasing the capacity of an SC-FDMA cellular system. Working together with open-loop Fractional Power Control (PFC), time-dependent scheduling (to maintain fairness constraints to all users), opportunistic scheduling in frequency domain (FD, intended to improve the overall throughput) and adaptive modulation and coding schemes (AMCS), our simulations show that our novel scheme outperforms other typical resource allocation schemes by reducing the dropping probability and increasing the supported traffic load, while guaranteeing the required level of Quality of Service (QoS) for real-time traffic.

Impact of ICI management schemes on packet scheduling strategies in OFDMA systems

In this paper, we analyze the behavior of several radio resource scheduling strategies under different power and subcarrier allocation (PSA) and inter-cell interference (ICI) coordination schemes in mobile OFDMA networks. The aim is to test the capability of these scheduling strategies to deal with quality of service (QoS) requirements both in a single-service scenario or when a mixture of services takes place. This work shows that radio resource allocation schemes managing ICI have strong impact on the scheduling policy behavior, and that traffic delay is a key parameter to track in order to provide QoS when services with different delay constraints simultaneously occur.

Performance evaluation of nonsynchronized initial random access for mobile broadband systems

In this paper, a comparative analysis of the performance of the nonsynchronized initial random access channel in Mobile WiMAX and E-UTRA systems under different conditions (fast fading, multiuser interference) is carried out. The analysis is focused on the correlation properties of the code sequences used in each case. We evaluate their ability to provide low values for false alarm and erroneous detection probabilities (detecting a sequence that has not been transmitted) at the same time as guaranteeing low nondetection probabilities of the effectively transmitted sequences. Results show the promising performance of the E-UTRA scheme, even in high mobility scenarios, where the Doppler effect requires additional considerations to guarantee the correct system operation.

Comparative Analysis of Non-Synchronized Initial Random Access for Mobile Broadband Systems

In this paper, a comparative analysis of the performance of the non-synchronized initial random access channel in Mobile WiMAX and E-UTRA systems under different conditions (fast fading, multiuser interference) is carried out. The analysis is focused on the correlation properties of the code sequences used in each case. We evaluate their ability to provide low values for false alarm and erroneous detection probabilities (detecting a sequence that has not been transmitted) at the same time as guaranteeing low non detection probabilities of the effectively transmitted sequences.

Channel aware deferring strategies to improve packet scheduling in OFDMA systems

In this paper, we analyze the performance gain achieved when a channel-aware deferring (CaD) strategy is applied to defer the allocation of users with transitory bad channel state in a mobile OFDMA system. Users with good channel conditions receive more resources and the radio resource utilization improves. To reduce the impact of the CaD strategy on the quality of service (QoS) provisioning for the deferred users, a delay-dependent criterion is also applied. We show that the CaD significantly reduces both the dropping rate and the mean delay for the most restrictive traffic in a multi-service scenario, under a certain power and subcarrier allocation (PSA) algorithm that efficiently controls the inter-cell interference (ICI).

User based vs. frequency based resource occupation ordering in packet scheduling in OFDMA systems

In this paper, we compare the performance attained by several scheduling policies when the resource allocation is performed in a per-user or in a per-frequency resource ordering. We test the capability of both approaches to deal with the quality of service (QoS) provisioning in a multi-service scenario in a mobile OFDMA network. We probe that the comparative performance of these two approaches depends on the actual scheduling policy, under a certain power and subcarrier allocation (PSA) algorithm that efficiently controls the inter-cell interference (ICI).