Link Resource Adaptation for Multiantenna Bit-Interleaved Coded Multicarrier Systems

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Fairness-Adaptive Goodput-Based Resource Allocation in OFDMA Downlink with ARQ

We present a cross-layer resource-allocation (RA) scheme for the downlink in orthogonal frequency-division multiple-access (OFDMA) systems with fairness control among the users, where the resources to be allocated are power, bits per symbol, and subchannels. The use of subchannels, which are defined as group of subcarriers, leads to reducing the complexity of the bandwidth allocation compared with the commonly adopted subcarrier allocation. A goodput-based optimization function, which is derived by combining automatic repeat request (ARQ) and physical (PHY)-layer parameters, is used to perform RA for applications that demand error-free transmissions. Two transmission strategies are considered, with and without concatenation of subchannels, for which two different RA methods are developed, respectively. We also propose an algorithm that improves the complexity associated to both concatenation and nonconcatenation schemes, without appreciable performance loss.The work was supported by the GRE3N Project under Grant TEC2011-29006-C03-03.Publicad

Cross-layer link adaptation for goodput optimization in MIMO BIC-OFDM systems

This work proposes a novel cross-layer link performance prediction (LPP) model and link adaptation (LA) strategy for soft-decoded multiple-input multiple-output (MIMO) bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) systems employing hybrid automatic repeat request (HARQ) protocols. The derived LPP, exploiting the concept of effective signal-to-noise ratio mapping (ESM) to model system performance over frequency-selective channels, does not only account for the actual channel state information at the transmitter and the adoption of practical modulation and coding schemes (MCSs), but also for the effect of the HARQ mechanism with bit-level combining at the receiver. Such method, named aggregated ESM, or αESM for short, exhibits an accurate performance prediction combined with a closed-form solution, enabling a flexible LA strategy, that selects at every protocol round the MCS maximizing the expected goodput (EGP), i.e., the number of correctly received bits per unit of time. The analytical expression of the EGP is derived capitalizing on the αESM and resorting to the renewal theory. Simulation results carried out in realistic wireless scenarios corroborate our theoretical claims and show the performance gain obtained by the proposed αESM-based LA strategy when compared with the best LA algorithms proposed so far for the same kind of systems

A robust resource allocation algorithm for packet BIC-UFMC 5G wireless communications

In this paper, we present a novel resource allocation (RA) algorithm for packet Universal Filtered Multi-Carrier (UFMC) BIC-based communications, the latter being a novel modulation format possibly envisaged to be applied in 5G wireless systems. Assuming the perfect knowledge of the channel and capitalizing on the specific UFMC signal waveform, the proposed RA strategy optimizes the coding rate and bit loading within the overall bandwidth along with the per-subband power distribution. In the presence of a carrier offset and over fading selective channels, the results we obtained are twofold: i) the UFMC format reveals to be more robust than the conventional OFDM scheme; ii) the performance of the UFMC system itself is further boosted by the optimal choice of radio resources evaluated by the proposed RA algorithm

GOODPUT BASED ADAPTIVE MODULATION AND CODING ALGORITHM FOR BIC-OFDM SYSTEMS

WiMAX IEEE 802.16m standard description and implementation of simulation software. SISO and MIMO techniques(open loop and closed loop) implementation and resultis validation. A novel physical abstraction and Link layer prediction for 802.16m MIMO BIC-OFDM system based on goodput maximization: Effective SNR mapping, with low complexity but same performance or even better compared with MIESM, called novel kESM. Theoretical derivation of novel kESM physical abstraction technique, comparison between kESM and MI-ESM / EESM. Goodput oriented adaptive modulation and coding algorithm for BIC-OFDM wireless system based on above-mentioned abstraction. Theoretical derivation and dissertation. Simulations of 802.16m WiMAX system using C++ and C++ with IT++ libraries(used in NEWCOMM++ project). Various graphic rapresentation for different modulation and coding schemas, dissertation abuot visual and practical results

Radio resource allocation for uplink OFDMA systems with finite symbol alphabet inputs

In this paper, we consider the radio resource allocation problem for uplink orthogonal frequency-division multiple-access (OFDMA) systems. The existing algorithms have been derived under the assumption of Gaussian inputs due to its closed-form expression of mutual information. For the sake of practicality, we consider the system with finite symbol alphabet (FSA) inputs and solve the problem by capitalizing on the recently revealed relationship between mutual information and minimum mean square error (MMSE). We first relax the problem to formulate it as a convex optimization problem, and then, we derive the optimal solution via decomposition methods. The optimal solution serves as an upper bound on the system performance. Due to the complexity of the optimal solution, a low-complexity suboptimal algorithm is proposed. Numerical results show that the presented suboptimal algorithm can achieve performance very close to the optimal solution and that it outperforms the existing suboptimal algorithms. Furthermore, using our proposed algorithm, significant power saving can be achieved in comparison to the case when a Gaussian input is assumed

Adaptive Techniques for Packet-Oriented Transmissions in Future Multicarrier Wireless Systems

I sistemi wireless dei prossimi anni sono tenuti a fornire trasmissioni caratterizzate da data rate e affidabilità sempre maggiori per sostenere la sempre più crescente richiesta di applicazioni e servizi eterogenei. Inoltre, tali requisiti devono essere soddisfatti nel difficile ambiente di propagazione rappresentato dal canale wireless, e devono far fronte alla scarsità dello spettro radio disponibile. Per tali sistemi, la tecnica di modulazione multiportante nota come orthogonal frequency division multiplexing (OFDM) è emersa come tecnologia chiave a livello fisico grazie alla sua elevata efficienza spettrale, struttura di ricetrasmissione piuttosto semplice e robustezza al fenomeno di multipath fading. In tale contesto, questa tesi indaga nuove tecniche adattative in cui le risorse e parametri di trasmissione sono adattati in base alle informazioni sullo stato di canale al fine di fornire una consegna affidabile ed efficiente di pacchetti dati su canali selettivi in frequenza. Queste tecniche, note in letteratura come link resource adaptation (LRA) e resource allocation (RA), sono proposte in combinazione con un numero di funzionalità avanzate come l'efficiente tecnica di codifica di canale chiamata bit interleaved coded modulation (BICM) e meccanismi di hybrid automatic repeat request (HARQ). Diversamente dalla maggior parte dei problemi di LRA e RA considerati nella letteratura, questa tesi si basa sul goodput come figura di merito, definito come il numero di bit di informazione consegnati in pacchetti senza errori per unità di tempo. Quest'ultimo rappresenta, infatti, una metrica adeguata per dare un quadro attendibile delle effettive prestazioni del collegamento caratterizzato da modulazione e codifici pratici, trasmissioni a pacchetto e meccanismi di HARQ. In dettaglio, i contributi principali della tesi sono: la derivazione di una strategia di LRA che assegna modulazione, tasso di codifica e potenza ad un sistema BIC-OFDM cognitivo; un nuovo metodo di predizione delle prestazioni, che sfrutta la metodologia di effective signal-to-noise ratio (SNR), per sistemi BIC-OFDM impieganti protocolli di HARQ con packet combining; un algoritmo di LRA che seleziona la migliore distribuzione dei bit e tasso di codifica per sistemi BIC-OFDM; uno schema equo di RA che assegna potenza, ordine di modulazione, tasso di codifica e sottoportanti agli utenti sul downlink di un sistema BIC orthogonal frequency division multiple access (OFDMA) col fine di ottimizzare le prestazioni dell'utente avente il valore più basso di goodput

D13.2 Techniques and performance analysis on energy- and bandwidth-efficient communications and networking

Deliverable D13.2 del projecte europeu NEWCOM#The report presents the status of the research work of the various Joint Research Activities (JRA) in WP1.3 and the results that were developed up to the second year of the project. For each activity there is a description, an illustration of the adherence to and relevance with the identified fundamental open issues, a short presentation of the main results, and a roadmap for the future joint research. In the Annex, for each JRA, the main technical details on specific scientific activities are described in detail.Peer ReviewedPostprint (published version