Multi-Antenna System Performance and Impairments in Long Term Evolution Radio Access Networks Using the Extended Spatial Channel Model
Notice bibliographique
Résumé
Consumer demand for rich content delivered to portable wireless devices is pushing the wireless industry and researchers to find ways to improve the efficiency of wireless networks.New technologies like LTE and LTE-Advanced are being refined and deployed to meet demands.This thesis studies three important areas of wireless communications using LTE; phase noise, Doppler and link adaptation and the performance of various multiple antenna systems.The thesis focuses on the performance of 4 base station antennas and results obtained with the advanced 3 rd Generation Partnership Project's (3GPP) extended spatial channel model (SCME).Simulations show the effect of each impairment and configuration on the LTE physical downlink shared channel.The best performing antenna configuration evaluated is the 4-transmitter, 4-port, correlated cross-polarized BS antenna when TM4's closed-loop spatial multiplexing is used.The results show that a 4 antenna BS setup provides gain over 2 BS antennas, despite the additional reference signal overhead, due to the greater set of precoding matrices available with 4 antenna ports.When only 2 ports are available, TM3's open-loop spatial multiplexing (OLSM) performs better than TM4 as the user equipment (UE) becomes mobile, since 2-port TM3 is less dependent on the channel state information.The practical implementation issues of link adaptation are shown to cause a significant drop in throughput at medium and high UE velocities.The results in the thesis suggest that improving the latency of the link adaptation loop with low complexity algorithms, or an increase in processing power, along with adaptive link adaptation reporting intervals can keep uplink overhead low and maintain a higher throughput as velocity increases.The UE velocity is also pushed to extremes in the high speed train on railway simulations and shows that LTE can operate with some throughput degradation at 350 km/hr.Finally, the LTE downlink is also subjected to phase noise; an important impairment present in communication systems employing up/down-conversion.The generated phase noise and the measured phase noise simulations show the effect of phase noise on the throughput.As expected, the relatively quiet measured phase noise does not significantly degrade the LTE downlink.iii I would like to thank my supervisor Prof. M. El-Tanany for his friendship and the genuine guidance he provided when I would ask for his help.He unselfishly lent me his time for any questions I had and occasional unrelated discussions about topics that interested us both.He provided encouragement along the way and allowed me to explore additional areas to satisfy my curiosity despite the extra time it would take to complete my thesis work.I'm very grateful for the opportunity he gave me to learn a new field, work on an interesting topic and meet a number of wonderful people along the way.I would also like thank my co-workers and mentors at Ericsson who often made themselves available (at any time) to discuss projects on which we were working.They inspired me since they had a tremendous amount of passion for the work they were performing.Thank you to
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,003 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».