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Over a long period of development of the network communication general user (NCGU), various models have been developed, focused on the service of voice traffic. In the next generation NGN heterogeneous communication network, voice traffic service has become one of the applications. This application was subject to stringent timing requirements (latency and loss). Further development took place to develop new applications that impose even more severe service requirements. Such applications have had a significant impact on the requirements and timing of next generation communications networks. In this regard, it was proposed in various recommendations to distinguish networks that provide services with strict requirements for time parameters into a new class of networks and call them networks with low and ultra-low delays.

Ο ταχύτατα εξελισσόμενος τομέας των δικτύων κινητών επικοινωνιών έχει επιφέρει μία ιδιαίτερα αυξανόμενη απαίτηση για ασύρματη, πολυμεσική επικοινωνία. Στη ραγδαία εξέλιξη του τομέα αυτού συμβάλουν τα μέγιστα και οι απαιτήσεις της σύγχρονης αγοράς για ένα ενοποιημένο και λειτουργικό σύστημα κινητής τηλεφωνίας παρέχοντας παράλληλα πληθώρα ευρυζωνικών υπηρεσιών ψηφιακού περιεχομένου στους πελάτες - χρήστες του. Είναι γεγονός ότι τα τελευταία χρόνια τα δίκτυα επικοινωνιών τρίτης γενιάς (3G) - Universal Mobile Telecommunication System (UMTS) γνωρίζουν μεγάλη άνθηση και η χρήση τους έχει επεκταθεί στις περισσότερες ευρωπαϊκές χώρες, όπως και στην Ελλάδα. Τα νέα αυτά κινητά δίκτυα αντικαθιστούν τα υπάρχοντα κινητά δίκτυα δεύτερης γενιάς και επιπλέον προσφέρουν προηγμένες υπηρεσίες στους κινητούς χρήστες. Ωστόσο, η αδήριτη ανάγκη για μεγαλύτερες (ευρυζωνικές) ταχύτητες πρόσβασης οδήγησε στην περαιτέρω ανάπτυξη των 3G δικτύων και στην υιοθέτηση νέων τεχνολογιών, με κυριότερο εκπρόσωπο τους την τεχνολογία High Speed Packet Access (HSPA). Η τεχνολογία HSPA αποτελεί τη φυσιολογική μετεξέλιξη του UMTS, η οποία πολλές φορές συναντάται και ως 3.5G ή 3G+, προκειμένου να δηλώσει την αναβάθμιση του 3G (UMTS) προτύπου. Ωστόσο, παρά το γεγονός ότι η τεχνολογία HSPA αναμένεται να προσφέρει τη δυνατότητα παροχής πληθώρας ευρυζωνικών υπηρεσιών, το 3rd Generation Partnership Project (3GPP), που αποτελεί τον οργανισμό που προτυποποιεί τις νέες τεχνολογίες και ορίζει τις προδιαγραφές τους, ήδη μελετά και επεξεργάζεται νέες τεχνολογίες που θα επικρατήσουν την αμέσως επόμενη δεκαετία στην αγορά των κινητών επικοινωνιών. Το νέο αυτό project αποκαλείται Long Term Evolution (LTE) και στοχεύει στην επίτευξη ακόμη υψηλότερων ρυθμών μετάδοσης σε συνδυασμό με την αξιοποίηση μεγαλύτερου εύρος ζώνης. Κύρια προοπτική του LTE αποτελεί η διασφάλιση της ανταγωνιστικότητας και η επικράτηση του προτύπου στο χρονικό ορίζοντα της επόμενης δεκαετίας. Κατά συνέπεια, η αγορά κινητών επικοινωνιών σταδιακά μεταλλάσσεται προς τη δημιουργία δικτύων κινητών επικοινωνιών επόμενης γενιάς, με απώτερο σκοπό την επίτευξη της αποκαλούμενης "Κινητής Ευρυζωνικότητας" (Mobile Broadband). Ταυτόχρονα με την εκτεταμένη εξάπλωση των δικτύων κινητών επικοινωνιών επόμενης γενιάς καθώς και τις αυξημένες δυνατότητες των κινητών συσκευών, οι πάροχοι πολυμεσικού περιεχομένου και υπηρεσιών ενδιαφέρονται όλο και περισσότερο για την υποστήριξη της πολυεκπομπής (multicasting) δεδομένων στα δίκτυα αυτά με σκοπό την αποτελεσματική διαχείριση και επαναχρησιμοποίηση των διαθέσιμων πόρων του δικτύου. Επιπρόσθετα, οι χρήστες των κινητών δικτύων έχουν πλέον την απαίτηση να προσπελαύνουν εφαρμογές και υπηρεσίες οι οποίες μέχρι σήμερα μπορούσαν να διατεθούν αποκλειστικά από τα συμβατικά ενσύρματα δίκτυα. Έτσι λοιπόν στις μέρες μας γίνεται λόγος για υπηρεσίες πραγματικού χρόνου όπως mobile TV, mobile gaming, mobile streaming κ.α. Ένα από τα σημαντικότερα βήματα των δικτύων κινητών επικοινωνιών προς την κατεύθυνση της παροχής νέων, προηγμένων πολυμεσικών υπηρεσιών είναι η εισαγωγή της υπηρεσίας Multimedia Broadcast / Multicast Service (MBMS). Η υπηρεσία MBMS έχει σαν κύριο σκοπό την υποστήριξη IP εφαρμογών πανεκπομπής (broadcact) και πολυεκπομπής (multicast), επιτρέποντας με αυτό τον τρόπο την παροχή υπηρεσιών υψηλού ρυθμού μετάδοσης σε πολλαπλούς χρήστες με οικονομικό τρόπο. Η multicast μετάδοση δεδομένων σε κινητά δίκτυα επικοινωνιών είναι μια σχετικά νέα λειτουργικότητα η οποία βρίσκεται ακόμη στο στάδιο των δοκιμών και της προτυποποίησης της. Ένας multicast μηχανισμός μεταδίδει τα δεδομένα μόνο μία φορά πάνω από κάθε ασύρματο σύνδεσμο που αποτελεί τμήμα των μονοπατιών προς τους προορισμούς-κινητούς χρήστες. Το κρισιμότερο σημείο που εντοπίζεται κατά τη multicast μετάδοση δεδομένων στα κινητά δίκτυα επικοινωνιών είναι ο αποτελεσματικός έλεγχος ισχύος. Οι σταθμοί βάσης των κυψελωτών αυτών δικτύων διαθέτουν περιορισμένους πόρους ισχύος, γεγονός που περιορίζει τη χωρητικότητα της κυψέλης (cell) και επιβάλλει τη χρήση μίας βέλτιστης στρατηγικής για την όσο το δυνατόν καλύτερη αξιοποίηση των διαθέσιμων πόρων ισχύος. Ο έλεγχος ισχύος στοχεύει στη μείωση της εκπεμπόμενης ισχύος, στην ελαχιστοποίηση του θορύβου στο κυψελωτό δίκτυο και κατά συνέπεια στη διασφάλιση μεγαλύτερης χωρητικότητας επιπλέον χρηστών. Ένα από τα βασικότερα στοιχεία του ελέγχου ισχύος στα δίκτυα κινητών επικοινωνιών επόμενης γενιάς κατά τη multicast μετάδοση πολυμεσικών δεδομένων αποτελεί η επιλογή του κατάλληλου καναλιού μεταφοράς για τη μετάδοση των δεδομένων στον κινητό χρήστη. Συγκεκριμένα, πρόκειται για ένα κρίσιμο ζήτημα το οποίο είναι ακόμα υπό εξέταση στο 3GPP. Προς την κατεύθυνση αυτή, στο MBMS πρότυπο έχουν αναπτυχθεί διάφοροι μηχανισμοί, με χαρακτηριστικό τον MBMS Counting Mechanism. Στόχος του μηχανισμού αυτού είναι η βελτιστοποίηση της ροής δεδομένων για την υπηρεσία MBMS, όταν αυτά διέρχονται από τις διεπαφές του UMTS/HSPA δικτύου. Ωστόσο, η υπάρχουσα μορφή του μηχανισμού αυτού, καθώς και των αρκετών άλλων μηχανισμών που έχουν προταθεί από το 3GPP, διακρίνεται από πολλές αδυναμίες που δεν επιτρέπουν την αποτελεσματική και μαζική μετάδοση πολυμεσικών δεδομένων. Τα σημαντικότερα προβλήματα των μηχανισμών αυτών είναι η απουσία ευρυζωνικών χαρακτηριστικών καθώς και η σπατάλη σημαντικού τμήματος των ούτως ή άλλως περιορισμένων πόρων ισχύος. Εν γένει, η επιλογή του κατάλληλου καναλιού μεταφοράς των πολυμεσικών δεδομένων στο ασύρματο μέσο είναι μια δύσκολη διαδικασία καθώς μια λανθασμένη επιλογή καναλιού μπορεί να οδηγήσει στην αστοχία μίας ολόκληρης κυψέλης. Γίνεται σαφές λοιπόν, ότι απαιτείται μία βελτιωμένη έκδοση των υπαρχόντων μηχανισμών για την αποτελεσματικότερη και οικονομικότερη μετάδοση πολυμεσικού περιεχομένου σε μεγάλο πλήθος χρηστών. Λαμβάνοντας υπόψη τα παραπάνω, στόχος της παρούσας διδακτορικής διατριβής είναι η μελέτη του ελέγχου ισχύος στα δίκτυα κινητών επικοινωνιών επόμενης γενιάς καθώς και η ανάπτυξη νέων μεθόδων/μηχανισμών για τη βελτιστοποίηση του. Ιδιαίτερο χαρακτηριστικό της διατριβής αυτής είναι η ενσωμάτωση και η "εκμετάλλευση" όλων των ιδιαίτερων χαρακτηριστικών της HSPA τεχνολογίας στην MBMS υπηρεσία. Προς αυτή την κατεύθυνση, στην παρούσα διδακτορική διατριβή αναλύονται και αξιολογούνται όλα τα υπάρχοντα κανάλια μεταφοράς του UMTS και της τεχνολογίας HSPA τα οποία μπορούν να χρησιμοποιηθούν για τη multicast μετάδοση MBMS υπηρεσιών. Η αξιολόγηση γίνεται με βάση την απαιτούμενη ισχύ που πρέπει να ανατεθεί από το σταθμό βάσης για καθένα από αυτά, και κατά συνέπεια με βάση το ρυθμό μετάδοσης τους, τον αριθμό των χρηστών που μπορούν να εξυπηρετήσουν, την ποιότητα υπηρεσιών για κάθε χρήστη, τη μέγιστη δυνατή κάλυψη της κυψέλης κ.α. Οι ιδιαίτερα αυξημένες απαιτήσεις των MBMS υπηρεσιών μας οδήγησαν στη συνέχεια στη διερεύνηση και αξιολόγηση ορισμένων τεχνικών μείωσης της εκπεμπόμενης ισχύος, με απώτερο σκοπό την αποδοτικότερη χρήση των πόρων του συστήματος κατά τη μετάδοση MBMS υπηρεσιών. Ενδεικτικά αναφέρουμε πως μία MBMS υπηρεσία με ρυθμό μετάδοσης 128 Kbps μπορεί να καταναλώσει έως και το 80% των πόρων ισχύος ενός σταθμού βάσης. Επομένως, γίνεται κατανοητό ότι η μετάδοση MBMS υπηρεσιών με τόσο υψηλούς ρυθμούς μετάδοσης καθίσταται δύσκολη έως και αδύνατη. Για την αντιμετώπιση αυτού του προβλήματος έχουν αναπτυχθεί τεχνικές, όπως η FACH Dynamic Power Setting, η Macro Diversity Combining και το Rate Splitting, ικανές να μειώσουν τα επίπεδα ισχύος κατά τη μετάδοση multicast δεδομένων στους MBMS χρήστες. Η διδακτορική αυτή διατριβή εξετάζει την αποδοτικότητα της χρήσης αυτών των τεχνικών εξοικονόμησης ισχύος και παρουσιάζει πειραματικά αποτελέσματα που αποκαλύπτουν το ποσό ισχύος που εξοικονομείται από κάθε μία τεχνική. Η αξιολόγηση τόσο των καναλιών μεταφοράς όσο και των τεχνικών μείωσης ισχύος θα οδηγήσει στην εύρεση ενός κατάλληλου σχήματος/μηχανισμού, ο οποίος θα εξασφαλίζει την αποδοτική εναλλαγή μεταξύ των διάφορων τύπων καναλιών κατά τη μετάδοση MBMS υπηρεσιών. Ο μηχανισμός αυτός, τον οποίο καλούμε MBMS Channel Assignment Mechanism (ή χάριν συντομίας "MCAM"), αναμένεται να εξασφαλίσει βελτιωμένη απόδοση σε σχέση με τους αντίστοιχους μηχανισμούς που έχουν προταθεί από το 3GPP, μείωση της καταναλισκόμενης ισχύος και κατά συνέπεια αύξηση της χωρητικότητας των κινητών δικτύων επόμενης γενιάς. Ωστόσο, το πιο αξιοπρόσεκτο πλεονέκτημα του προτεινόμενου μηχανισμού, που ουσιαστικά τον διαφοροποιεί από τις άλλες προσεγγίσεις, είναι ότι προσαρμόζεται στις αυξημένες απαιτήσεις των κινητών δικτύων επόμενης γενιάς για ταυτόχρονη παροχή πολλαπλών πολυμεσικών συνόδων. Το γεγονός αυτό μπορεί να επιτρέψει τη μαζική μετάδοση πολυμεσικών δεδομένων σε πληθώρα κινητών χρηστών, θέτοντας κατά τον τρόπο αυτό τον MCAM σαν έναν ισχυρό υποψήφιο για τα δίκτυα επόμενης γενιάς.

LTE (Long Term Evolution) is a 3GPP (Third Generation Partnership Project) wireless standards that gives us wideband CDMA (Code Division Multiple Access) and HSPA (High Speed Packet Access) a third generation connectivity. LTE is the fourth generation (4G) of wireless communication technologies that brings the standard OFDMA (Orthogonal Frequency Division Multiple Access) modulation , MUMIMO (Multiuser Multiple Input Multiple Output) technology and different multipath fading model EVA (Extended Vehicular a), ETU (Extended Typical Urban) and EPA (Extended Pedestrian A) which allows the operator to use spectrum more efficiently to deliver high speed data. This paper characterizes the downlink performance of LTE. There are many metric to characterize the performance, but one of the most convenient and informative metric is the BER (Bit Error Rate). So the performance is characterized in terms of BER. In this paper the LTE system is modeled and simulated using MATLAB and the BER for 2×2 and 4×4 MIMO using QPSK and 16QAM modulation is obtained against different SNR values. General Terms Mobile Communication

Wideband code division multiple access (WCDMA), high speed packet access (HSPA) and HSPA+ are third generation partnership project (3GPP) standards. These systems are the major wireless communication standards. In order to test the performance of WCDMA/HSPA/HSPA+ signal in a base station, the measurement hardware is required to the evaluation of the transmitted signals. In this paper, the algorithm for the performance measurement of the WCDMA/HSPA/HSPA+ is proposed. Also, the performance of the measurement algorithm is used to evaluate the generated signal by the WCDMA/HSPA/HSPA+ signal generator. Generally, the algorithm of normal modems cannot be applied to the measurement system because the signal measurement equipment needs to guarantee the high accuracy. So, the WCDMA/HSPA/HSPA+ signal measurement algorithm for the accurate measurement is proposed. By the simulation, it is confirmed that the proposed measurement algorithm has good performance compared with the specification. Therefore, the proposed algorithm can be usefully applied to verify the performance of the measurement using the simulation.

Multi-radio access technology (RAT) cellular communication systems limit connected users to utilizing a single RAT even when employing multi-mode user equipment (UE) capable of utilizing multi-RATs. Single-mode access, combined with static spectrum partitioning between co-deployed RATs and independent resource allocation for employed RATs, results in suboptimal spectrum utilization in multi-RAT systems. This paper models user access in multi-RAT systems and proposes enabling multi-mode UE to simultaneously utilize multiple RATs, using multi-RAT carrier aggregation, to improve the performance and spectrum utilization of multi-RAT systems. Several realizations of multi-mode access with varying implementation requirements are presented and discussed. Detailed system-level simulations, for a system co-deploying High Speed Packet Access (HSPA) and Long-Term Evolution (LTE), are performed to investigate the gains and limitations of different user access configurations in multi-RAT systems.

As internet services are being provided through a wireless acce ss, the importance of quality of experience (QoE) is stressed that is defined as the quality that indicates user's actual feeling when a service is provided. Unlike quality of service (QoS) that can be expressed as a numerical value, it is difficult to represent QoE in an objective way. If an internet service is serviced over a wireless channel, its QoE can be affected by a number of factors such as fading, mobility and so on. This paper, therefore, attempts to specify the relationship between QoE and QoS by conducting practical measurements for the voice service through 3G high speed packet access (HSPA) access network. Analysing the measured results, it has been shown that received signal strength indicator (RSSI) has a great influence on mean opinion score (MOS) through transmission delay.

The efficiency of high speed packet access (HSPA) systems is mainly based on Packet Scheduling Scheme which will be the key to influencing on the system performance and ensuring the service quality for the users. In this paper, we introduce a three step packet scheduling scheme to provide quality of services (QoS) guaranteed for high speed uplink packet access. Then, we proposed an improved packet scheduling algorithm based on QoS parameter for mixed service applications in order to meet the actual QoS needs of the different systems. This algorithm calculated the scheduling priority based on the comprehensive factors, including the queuing status of each user, QoS requirements and the sum of speeds on each channel. The simulation results show that the performance efficiency of HSPA systems employed proposed algorithm is superior compared to the conventional PF and M-LWDF algorithm in average packet drop and average cell throughput.

This paper presents a study on the HSPA+ technology and the impact it have on today's mobile communication networks. To this end we study how to use features such as MIMO (Multiple Input Multiple Output) and HOM (Higher Order Modulation) and how they can increase the data rate transfer per user. The extracted results show that we can increase the data transmission rate by varying the configuration of antennas and the modulation type, obtaining the maximum theoretical order of 43.8 Mbps and 23 Mbps in Downlink (DL) and Uplink (UL), respectively using 4x4 MIMO and 64-QAM (Quadrature Amplitude Modulation) modulation. These results are obtained based on the direct application or manipulation of existing models and integrated in a simulator implemented for this purpose.

Initially developed for use in fixed networks, the ARQ (Automatic Repeat Request) technique was adopted in UMTS systems aiming the QoS improvement for data transmission. However, real time services like VoIP cannot benefits of ARQ, because of the related delay problems in WCDMA systems. With the advent of HSPA (High Speed Packet Access) and the LTE (Long Term Evolution) networks, there was a consequent redefinition of the ARQ functionalities, aiming to become possible to use it for real time services. Delay problems were minimized as a consequence of the facilities introduced for the new methods of ARQ generation. The main objective of this work is the definition of a methodology toward ARQ optimization relatively to the mean power required to transfer the information from the origin to the destination, accordingly to a given error probability.To reduce the amount of the power transfer in the uplink direction is of paramount importance for the minimization of interference levels as well as to economize battery of cellular equipment.Though the treatment here presented is focused to E-DCH (Enhanced Uplink Dedicated Channel) of HSPA systems, the results obtained are applicable to other related networks using ARQ techniques.

In this article, compliance boundaries and allowed output powers are determined for the front, back, and side of multiple-frequency base station antennas, based on the root-mean-squared electric field, the whole-body averaged specific absorption rate (SAR), and the 10 g averaged SAR in both the limbs and the head and trunk. For this purpose, the basic restrictions and reference levels defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for both the general public and occupational exposure are used. The antennas are designed for Global System for Mobile Communications around 900 MHz (GSM900), GSM1800, High Speed Packet Access (HSPA), and Long Term Evolution (LTE), and are operated with output powers at the individual frequencies up to 300 W. The compliance boundaries are estimated using finite-difference time-domain simulations with the Virtual Family Male and have been determined for three directions with respect to the antennas for 800, 900, 1800, and 2600 MHz. The reference levels are not always conservative when the radiating part of the antenna is small compared to the length of the body. Combined compliance distances, which ensure compliance with all reference levels and basic restrictions, have also been determined for each frequency. A method to determine a conservative estimation of compliance boundaries for multiple-frequency (cumulative) exposure is introduced. Using the errors on the estimated allowed powers, an uncertainty analysis is carried out for the compliance distances. Uncertainties on the compliance distances are found to be smaller than 122%. Bioelectromagnetics. 34:465–478. © 2013 Wiley Periodicals, Inc.

In this paper an innovative Radio Resource Management (RRM) algorithm is proposed with the purpose of increasing High Speed Packet Access (HSPA) performances, in terms of system capacity and service quality, when the Multimedia Broadcast Multicast Services (MBMS) is supplied. The proposed RRM algorithm exploits channel quality indications to set up point-to-multipoint connections to subgroups of multicast users and to select the proper modulation and coding schemes on the downlink. The number of subgroups is determined through an optimization technique that also takes into account the user satisfaction. An exhaustive simulation campaign is conducted to compare the proposed algorithm with the most promising approaches in the literature. Comparisons aim to assess the capability of the proposed RRM algorithm to efficiently manage group oriented services by providing an increment in terms of user satisfaction., Comment: Broadband Multimedia Systems and Broadcasting (BMSB), 2011 IEEE International Symposium on

This paper presents an empirical study on the performance of mobile High Speed Packet Access (a 3.5G cellular standard usually abbreviated as HSPA) networks in Hong Kong via extensive field tests. Our study, from the viewpoint of end users, covers virtually all possible mobile scenarios in urban areas, including subways, trains, off-shore ferries, and city buses. We have confirmed that mobility has largely negative impacts on the performance of HSPA networks, as fast-changing wireless environment causes serious service deterioration or even interruption. Meanwhile, our field experiment results have shown unexpected new findings and thereby exposed new features of the mobile HSPA networks, which contradict commonly held views. We surprisingly find out that mobility can improve fairness of bandwidth sharing among users and traffic flows. Also, the triggering and final results of handoffs in mobile HSPA networks are unpredictable and often inappropriate, thus calling for fast reacting fallover mechanisms. Moreover, we find that throughput performance does not monotonically decrease with increased mobility level. We have conducted in-depth research to furnish detailed analysis and explanations to what we have observed. We conclude that mobility is a double-edged sword for HSPA networks. To the best of our knowledge, this is the first public report on a large-scale empirical study on the performance of commercial mobile HSPA networks.

The Long Term Evolution (LTE) system is already able to provide a background of variety services for mobile users with multimedia services such as audio, video, and data. In fact, the High Speed Packet Access plus (HSPA+) solution can greatly enhance bit rates on down-link. However, the supporting for multimedia applications with different QoS (Quality of Service) requirements is not devised yet. Hence, in this paper we propose an effective packet scheduling algorithm based on Proportional Fairness (PF) scheduling algorithms for the LTE. In this proposed packet scheduling scheme, we optimized instantaneous user data rates and the traffic class weight which prioritize user`s packets. Finally, we evaluated and showed the performance of the proposed scheduling algorithm through simulations of multimedia traffics being transmitted to users over LTE links in a multi-cell environment.

HSPA(High Speed Packet Access)/HSPA+ is a combined 3GPP(Third Generation Partnership Project) standard of HSDPA(High Speed Downlink Packet Access) and HSUPA(High Speed Uplink Packet Access). The standard can provide the high speed multimedia service against the 3GPP release 99 standard. In order to test the 3GPP HSPA/HSPA+ terminal performance, the measurement hardware is required for the evaluate the transmitted signal of HSPA/HSPA+ terminals. Agilent Technologies and Innowireless produce the measurement equipments for HSPA/HSPA+ terminals. Generally speaking, the receiving algorithms in normal modems cannot be used directly to the measurement system due to the lack of the algorithm accuracy. In this paper, we propose the new receiver algorithm for precise measurement of 3GPP HSPA/HSPA+ terminal signal, and implement measurement functionality for performance measurement of the 3GPP HSPA/HSPA+ terminal by using software. The proposed 3GPP HSPA/HSPA+ signal measurement algorithm can be used for the commercial system through code execution speed optimization.

The high-speed downlink packet access (HSDPA) system can effectively support real-time voice services if the HS-SCCH-less feature is adopted in the 3GPP Release 7 standard. In this paper, we point out that the feature only offers a limited statistical multiplexing capability and it also causes serious power consumption at the user equipment. This paper proposes an HSDPA scheduling operation that utilizes the entire code space and considers the packet generation pattern of voice services.

A large number of phone calls and data services will take place in indoor environments. In Long Term Evolution (LTE), femtocell, as a home base station for indoor coverage extension and wideband data service, has recently gained significant interests from operators and consumers. Since femtocell is frequently turned on and off by a personal owner, not by a network operator, one of the key issues is that femtocell should be identified autonomously without system information to support handover from macrocell to femtocell. In this paper, we propose a dynamic reservation scheme of Physical Cell Identities (PCI) for 3GPP LTE femtocell systems. There are several reserving types, and each type reserves a different number of PCIs for femtocell. The transition among the types depends on the deployed number of femtocells, or the number of PCI confusion events. Accordingly, flexible use of PCIs can decrease PCI confusion. This reduces searching time for femtocell, and it is helpful for the quick handover from macrocell to femtocell. Simulation results show that our proposed scheme re- duces average delay for identifying detected cells, and increases network capacity within equal delay constraints. The 3rd Generation Partnership Project (3GPP) is work- ing on the standardization of asynchronous communication systems. This technology is being enhanced gradually en- suring higher user data rate, bigger system capacity, and lower cost. The wideband CDMA (WCDMA) system is standardized with 3GPP release 99/4 which is being de- ployed in the world. Release 5 is related to High Speed Downlink Packet Access (HSDPA), and it improves the downlink packet transmission speed theoretically up to 14.4 Mbps. High Speed Uplink Packet Access (HSUPA) is enhanced up to 5.76 Mbps in uplink, and it is standardized with the Release 6. We simply mention both HSDPA and HSUPA as High Speed Packet Access (HSPA). In release 7, High Speed Packet Access Evolution (eHSPA, HSPA+) is standardized. eHSPA is based on the HSPA network with a simple upgrade, and it supports more bandwidth efficiency and lower latency. The maximum data rate is 28.8 Mbps in downlink and 11.5 Mbps in uplink (1). How- ever, users still require further system improvements. The technology is dramatically enhanced in release 8, where the standard of Long Term Evolution (LTE) is currently being established. The main objectives of LTE are higher data rates, lower latency, increased capacity, enhanced coverage, and an optimized system for the packet switching network (2). LTE also considers a femtocell, which is referred to as a home base station for an indoor coverage extension and overall network performance enhancement (3). Recently, LTE-Advanced standard targeting of 1Gbps for low mobil- ity is being discussed in release 9. We look into general features and requirements of fem- tocells. Important issues related to access control are de- scribed, followed by our contributions and organization of the paper.

Long term evolution (LTE) of 3GPP provides high bandwidth for data transfer. In the viewpoint of the LTE terminal baseband modem chip, these high data rates require more complex logics and memories than previous baseband modem chips in preceding technologies such as Wideband Code Division Multiple Access (W-CDMA), High Speed Downlink Packet Access (HSDPA), and High Speed Packet Access (HSPA). It may exhaust user equipment (UE)'s battery power quickly. Thus, LTE provides an enhanced discontinuous reception (DRX) to extend the UE's battery lifetime. In this work, we propose an adjustable power management using a hierarchical cascaded power gating (HCPG) and a hierarchical multi-level clock gating (HMLCG) with special regard for DRX framework. The test results from the designed ASIC show that optimal power saving was achieved by using the proposed adjustable power management.

International audience; The purpose of this study is to assess the mean RF power radiated by mobile telephones during voice calls in 3G VoIP (Voice over Internet Protocol) using an application well known to mobile Internet users, and to compare it with the mean power radiated during voice calls in 3G VoCS (Voice over Circuit Switch) on a traditional network. Knowing that the specific absorption rate (SAR) is proportional to the mean radiated power, the user's exposure could be clearly identified at the same time. Three 3G (High Speed Packet Access) smartphones from three different manufacturers, all dual-band for GSM (900 MHz, 1800 MHz) and dual-band for UMTS (900 MHz, 1950 MHz), were used between 28 July and 04 August 2011 in Paris (France) to make 220 two-minute calls on a mobile telephone network with national coverage. The places where the calls were made were selected in such a way as to describe the whole range of usage situations of the mobile telephone. The measuring equipment, called “SYRPOM”, recorded the radiation power levels and the frequency bands used during the calls with a sampling rate of 20,000 per second. In the framework of this study, the mean normalised power radiated by a telephone in 3G VoIP calls was evaluated at 0.75% maximum power of the smartphone, compared with 0.22% in 3G VoCS calls. The very low average power levels associated with use of 3G devices with VoIP or VoCS support the view that RF exposure resulting from their use is far from exceeding the basic restrictions of current exposure limits in terms of SAR.

In this paper, a power consumption model for both macrocell and microcell base stations is proposed. This model is validated by temporal power measurements on actual base stations, and an excellent agreement is obtained. Furthermore, the power consumption's evolution during the day is investigated by means of these measurements. The energy efficiency of three different wireless technologies is compared namely mobile Worldwide Interoperability for Microwave Access, Long Term Evolution and High Speed Packet Access. With the model proposed, the deployment tool Green Radio Access Network Design is implemented, which allows to design an energy-efficient access network for a predefined area. In general and with the assumptions made, a macrocell base station consumes about 4.4 times more than a microcell base station. However, a microcell base station is less energy efficient than a macrocell base station because of its lower coverage range. Despite this, it is still useful to introduce them in the network as the same coverage can be obtained with a lower total power consumption than with a network where only macrocell base stations are used. Copyright © 2012 John Wiley & Sons, Ltd.

We propose a generalized framework for handling Multiple-Input Multiple-Output (MIMO) schemes defined within the context of the Third Generation Partnership Project (3GPP) physical layer specifications. A detailed review of all the multi-antenna transmission techniques adopted by the 3GPP so far is firstly presented, starting from the Global System for Mobile (GSM) communications and passing through the High-Speed Packet Access (HSPA) releases to the very recent Long Term Evolution (LTE)-Advanced standard. Motivated by the outcome of this overview, we introduce the Transmit Matrix (TRAM) concept, that can include as special cases several MIMO systems (e.g. transmit diversity, spatial-multiplexing, etc.) regardless of the presence or not of a feedback channel. Our approach is based on the adoption of a novel measure called Necessary Transmit Information (NTI) and on its one-to-one correspondence with the TRAM. The last allows for a convenient alternative representation of a TRAM-based MIMO system model and serves the straightforward construction of NTI-codebooks for a wide range of transmission schemes. The indicative applications provided reveal the universal nature of the proposed methodology.

The tremendous emergence of different wireless technologies has created many opportunities for extending many Internet applications and services to the wireless domain, and has envisioned many new ones. When we refer to wireless networks, people thoughts go directly to the Wireless Fidelity (WiFi) technology. However, WiFi networks are one type of the wireless networks that have been used for several years on a small scale areas and buildings such as schools, offices, companies, restaurants, and airports. The other types of wireless networks that cover larger geographical areas are the third and fourth Generation wireless networks, abbreviated as 3G, 4G networks, respectively, which basically use the mobile infrastructure. Some examples of these networks are High Speed Packet Access (HSPA), Worldwide Interoperability for Microwave Access (WiMax), and Long Term Evolution (LTE). In this book chapter, when we refer to the wireless network, we refer to both types of networks unless we specify one of them.

The power consumption of wireless access networks will become an important issue in the coming years. In this study, the power consumption of base stations for mobile WiMAX (Worldwide Interoperability for Microwave Access), fixed WiMAX, UMTS (Universal Mobile Telecommunications System), HSPA (High-Speed Packet Access) and LTE (Long-Term Evolution) is modelled and related to the coverage. A new metric, the power consumption per covered area PC(area), is introduced, to compare the energy efficiency of the considered technologies for a basic reference configuration and a future extended configuration, which makes use of novel Multiple Input Multiple Output (MIMO) technology. The introduction of MIMO has a positive influence on the energy efficiency: for example, for a 4 x 4 MIMO system, PC(area) decreases with 63% for mobile WiMAX and with 50% for HSPA and LTE, compared to a Single Input Single Ouptut (SISO) system. However, a higher MIMO array size (i.e. a higher number of transmitting and receiving antennas) does not always result in a higher energy efficiency gain.

In this paper, the impact of the high speed packet access (HSPA) indoor network on the macrocell HSPA performance is studied based on field measurements. The indoor network configuration and the indoor antenna locations were varied for the measurements. The performance evaluation was based on data throughput and link quality parameters in downlink and in uplink. According to the measurement results an indoor network has an impact on the macrocell performance on both downlink and uplink. The downlink Ec/N0 and throughput measurements show degradation in signal quality and downlink performance close to indoor antennas. The uplink measurements indicate that indoor network users may raise uplink interference levels at macro cell and thus cause performance or coverage degradation. However, the impact measured close to the indoor network was rather local, thus it is still recommended to exchange a small portion of the macrocell performance for a significant indoor traffic boost gained by implementing an indoor network.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. The requirement to provide multimedia services with QoS support in mobile networks has led to standardization and deployment of high speed data access technologies such as the High Speed Downlink Packet Access (HSDPA) system. HSDPA improves downlink packet data and multimedia services support in WCDMA-based cellular networks. As is the trend in emerging wireless access technologies, HSDPA supports end-user multi-class sessions comprising parallel flows with diverse Quality of Service (QoS) requirements, such as real-time (RT) voice or video streaming concurrent with non real-time (NRT) data service being transmitted to the same user, with differentiated queuing at the radio link interface. Hence, in this paper we present and evaluate novel radio link buffer management schemes for QoS control of multimedia traffic comprising concurrent RT and NRT flows in the same HSDPA end-user session. The new buffer management schemes—Enhanced Time Space Priority (E-TSP) and Dynamic Time Space Priority (D-TSP)—are designed to improve radio link and network resource utilization as well as optimize end-to-end QoS performance of both RT and NRT flows in the end-user session. Both schemes are based on a Time-Space Priority (TSP) queuing system, which provides joint delay and loss differentiation between the flows by queuing (partially) loss tolerant RT flow packets for higher transmission priority but with restricted access to the buffer space, whilst allowing unlimited access to the buffer space for delay-tolerant NRT flow but with queuing for lower transmission priority. Experiments by means of extensive system-level HSDPA simulations demonstrates that with the proposed TSP-based radio link buffer management schemes, significant end-to-end QoS performance gains accrue to end-user traffic with simultaneous RT and NRT flows, in addition to improved resource utilization in the radio access network.

This paper is aimed at presenting the real-time High Speed Packet Access (HSPA) emulator that has been developed in the framework of the AROMA project. Real-time emulators allow reproducing realistic scenarios to test algorithms, strategies, protocols and applications under realistic conditions. Therefore, real-time emulators constitute a powerful tool to evaluate the end-user's Quality of Experience (QoE), which could not be achieved by means of off-line simulations. The presented emulator is integrated in the AROMA real-time testbed, which has been developed to provide a framework for demonstrating the benefits of the common radio resource management algorithms as well as the proposed end-to-edge Quality of Service (QoS) management techniques developed for all-IP beyond 3G heterogeneous wireless networks in the context of the AROMA project. This paper presents a qualitative description of the developed tool, emphasizing some interesting implementation details that may result helpful in the development of similar emulation platforms. Some illustrative results, showing the capabilities of the developed tool, are also presented and analyzed.

The third Generation Partnership Project (3GPP) addresses next generation IP-based OFDMA technology with Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. This new OFDMA-based air interface is utilized under Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and supported with a new flatter-IP core. This entire architecture is termed as 3GPP EPS (Evolved Packet System); previously network architecture was called System Architecture Evolution (SAE). Note that LTE air interface is a successor of GSM/EDGE and UMTS/HSxPA network technologies but has the ability to support bandwidths wider than 5 MHz, and EPS network architecture considers reduction of network level elements compared with HSPA (High Speed Packet Access).

With the introduction of the Internet in the early 90th years of the last century, broadband demand has increased tremendously. As ISDN was the modern technology at that time, which has had its correspondence in the mobile world in the GSM technology, DSL and its evolution has its correspondence in UMTS/3G and its evolution into HSPA (High Speed Packet Access) and soon in LTE (Long Term Evolution). With the globalisation of our industries business has changed during the last 15 years. Employees are not anymore sitting eight hours a day in an office. They stroll around and need access to the Internet when out of office anytime anywhere. New categories have been born: the mobile worker and the mobile Internet. Does the mobile Internet have an implication on future communication’s behaviours of mobile workers? When mobile workers are already familiar with mobile broadband service access, do they need fixed broadband access in parallel? Would that be economical and productive? Some studies regarding the mobile Internet are already out. Researchers of Wildau University want to have more knowledge on this subject, but even more on the aspect, whether LTE could replace fixed broadband. Therefore, they have undertaken a study in the Berlin area to get a better understanding on different kinds of broadband access and give an answer to the question: LTE and Fixed Broadband – Competition or New Challenge? To put a long debate short, the answer is yes: LTE is a challenge and depending on the finance model it could be a strong competitor to fixed broadband as well.

The established success of wireless communications in terms of high data rates provision is undoubtedly owed to several combinations of different mechanisms. Such a combination is the well-known forward error correction (FEC) mechanism that combines automatic-repeat-request (ARQ) protocol and error correction capabilities. Furthermore, in the last decade, a cross-layer design provides the combination of different mechanisms across the layers and thus the performance gain is increased in wireless communications over fading channels. In this paper, we present a practical cross-layer design implementation that combines adaptive modulation and coding (AMC) and hybrid ARQ at the physical and data link layer by using different error correction schemes. Our implementation is based on a cross-layer design of AMC and HARQ. We perform simulations with different channel coding and modulation schemes that are implemented in broadband wireless access networks as IEEE 802.16 and 3GPP HSPA and thus the results obtained show the performance achieved by this practical cross-layer implementation in terms of spectral efficiency in two main broadband wireless access networks available into the market. Copyright © 2010 Inderscience Enterprises Ltd.