Mobile Communications Beyond 52.6 GHz: Waveforms, Numerology, and Phase Noise Challenge

In this article, the first considerations for the 5G New Radio (NR) physical layer evolution to support beyond 52.6GHz communications are provided. In addition, the performance of both OFDM based and DFT-s-OFDM based networks are evaluated with special emphasis on the phase noise (PN) induced distortion. It is shown that DFT-s-OFDM is more robust against PN under 5G NR Release 15 assumptions, namely regarding the supported phase tracking reference signal (PTRS) designs, since it enables more effective PN mitigation directly in the time domain. To further improve the PN compensation capabilities, the PTRS design for DFT-s-OFDM is revised, while for the OFDM waveform a novel block PTRS structure is introduced, providing similar link performance as DFT-s-OFDM with enhanced PTRS design. We demonstrate that the existing 5G NR Release 15 solutions can be extended to support efficient mobile communications at 60GHz carrier frequency with the enhanced PTRS structures. In addition, DFT-s-OFDM based downlink for user data could be considered for beyond 52.6GHz communications to further improve system power efficiency and performance with higher order modulation and coding schemes. Finally, network link budget and cell size considerations are provided, showing that at certain bands with specific transmit power regulation, the cell size can eventually be downlink limited.Comment: This manuscript has been submitted to IEEE Wireless Communications Magazine (WCM). 8 pages, 4 figures, and 2 table

A review of traditional cost system versus activity based costing approaches

In the last two decades, business environment has been changing rapidly with fierce global competition. Firms using the traditional costing system were forced to change from their old system traditional-cost method and to accept the newer cost system, better known as the activity based on costing (ABC system). The new system is able to support and enhance decision making of the decision makers, besides being adaptable to the new business environment. Therefore, this paper aimed to review the applications and importance of both traditional cost system and ABC system for business decision making, and compare the results of ABC and the traditional costing systems via literature reviews of works by previous authors. The results reflected that activity based on the costing system is a better system comparing to the traditional costing systems. ABC system enhances decision making of the interested user with its better adaptable costing features to support the new business environment and global business competition. It thus creates a more sustainable source of competitive advantage. In addition, it identifies the under-costed and over-costed of the products of a firm

5G New Radio Evolution Towards Sub-THz Communications

In this paper, the potential of extending 5G New Radio physical layer solutions to support communications in sub-THz frequencies is studied. More specifically, we introduce the status of third generation partnership project studies related to operation on frequencies beyond 52.6 GHz and note also the recent proposal on spectrum horizons provided by federal communications commission (FCC) related to experimental licenses on 95 GHz - 3 THz frequency band. Then, we review the power amplifier (PA) efficiency and output power challenge together with the increased phase noise (PN) distortion effect in terms of the supported waveforms. As a practical example on the waveform and numerology design from the perspective of the PN robustness, link performance results using 90 GHz carrier frequency are provided. The numerical results demonstrate that new, higher subcarrier spacings are required to support high throughput, which requires larger changes in the physical layer design. It is also observed that new phase-tracking reference signal designs are required to make the system robust against PN. The results illustrate that single-carrier frequency division multiple access is significantly more robust against PN and can provide clearly larger PA output power than cyclic-prefix orthogonal frequency division multiplexing, and is therefore a highly potential waveform for sub-THz communications.Comment: This manuscript has been accepted for publication to IEEE 6G Wireless Summit 2020, 6 pages, 4 figure

A Comparative Review of Improvements in Long Term Evolution

Long Term Evolution (LTE) is one of the major technologies on the rise in the world as of today. It is a 4G network launched by the Third Generation Partnership Project (3GPP). LTE Release 8 was the first standard that launched LTE network with an entire change of radio interface and core network. It was designed to offer higher data rate and capacity over mobile networks to accommodate increase in the number of users and data services. In addition the design was made to support simplified architecture with only packet switched services in order to ensure negligible interference; hence supporting real time application with reduced latency and higher efficiency. Furthermore, the continuous growth in data usage has created a need to take an evolutionary step for an efficient and continuous development of LTE. This step has brought about more upgrades and releases such as 3GPP Release 10, Release 11 and Release 12, otherwise known as LTE Advanced (LTE-A). It is widely believed that this will offer robust management of anticipated growth in network technology. This work reviews the improvements in LTE Advanced technology

LTE Spectrum Sharing Research Testbed: Integrated Hardware, Software, Network and Data

This paper presents Virginia Tech's wireless testbed supporting research on long-term evolution (LTE) signaling and radio frequency (RF) spectrum coexistence. LTE is continuously refined and new features released. As the communications contexts for LTE expand, new research problems arise and include operation in harsh RF signaling environments and coexistence with other radios. Our testbed provides an integrated research tool for investigating these and other research problems; it allows analyzing the severity of the problem, designing and rapidly prototyping solutions, and assessing them with standard-compliant equipment and test procedures. The modular testbed integrates general-purpose software-defined radio hardware, LTE-specific test equipment, RF components, free open-source and commercial LTE software, a configurable RF network and recorded radar waveform samples. It supports RF channel emulated and over-the-air radiated modes. The testbed can be remotely accessed and configured. An RF switching network allows for designing many different experiments that can involve a variety of real and virtual radios with support for multiple-input multiple-output (MIMO) antenna operation. We present the testbed, the research it has enabled and some valuable lessons that we learned and that may help designing, developing, and operating future wireless testbeds.Comment: In Proceeding of the 10th ACM International Workshop on Wireless Network Testbeds, Experimental Evaluation & Characterization (WiNTECH), Snowbird, Utah, October 201

4G Technology Features and Evolution towards IMT-Advanced

Kiinteiden- ja mobiilipalveluiden kysyntä kasvaa nopeasti ympäri maailmaa. Älykkäiden päätelaitteiden, kuten iPhone:n ja Nokia N900:n markkinoilletulo yhdistettynä näiden korkeaan markkinapenetraatioon ja korkealuokkaiseen käyttäjäkokemukseen lisäävät entisestään palveluiden kysyntää ja luovat tarpeen jatkuvalle innovoinnille langattomien teknologioiden alalla tavoitteena lisäkapasiteetin ja paremman palvelunlaadun tarjoaminen. Termi 4G (4th Generation) viittaa tuleviin neljännen sukupolven mobiileihin langattomiin palveluihin, jotka International Telecommunications Union:in Radiocommunication Sector (ITU-R) on määritellyt ja nimennyt International Mobile Telecommunications-Advanced (IMT-Advanced). Nämä ovat järjestelmiä, jotka pitävät sisällään IMT:n ne uudet ominaisuudet, jotka ylittävät IMT-2000:n vaatimukset. Long Term Evolution-Advanced (LTE-Advanced) ja IEEE 802.16m ovat IMT-A sertifiointiin lähetetyt kaksi pääasiallista kandidaattiteknologiaa. Tässä diplomityössä esitellään kolmannen sukupolven järjestelmien kehityspolku LTE:hen ja IEEE 802.16e-2005 asti. Lisäksi työssä esitetään LTE-Advanced:n ja IEEE 802.16m:n uudet vaatimukset ja ominaisuudet sekä vertaillaan näiden lähestymistapoja IMT-A vaatimusten täyttämiseksi. Lopuksi työssä luodaan katsaus LTE ja IEEE 802.16e-2005 (markkinointinimeltään Mobile WiMAX) -järjestelmien markkinatilanteeseen.The demand for affordable bandwidth in fixed and mobile services is growing rapidly around the world. The emergence of smart devices like the iPhone and Nokia N900, coupled with their high market penetration and superior user experience is behind this increased demand, inevitably driving the need for continued innovations in the wireless data technologies industry to provide more capacity and higher quality of service. The term "4G" meaning the 4th Generation of wireless technology describes mobile wireless services which have been defined by the ITU's Radiocommunication Sector (ITU-R) and titled International Mobile Telecommunications-Advanced (IMT-Advanced). These are mobile systems that include the new capabilities of IMT that go beyond those of IMT-2000. Long Term Evolution-Advanced (LTE-Advanced) and IEEE 802.16m are the two main candidate technologies submitted for IMT-Advanced certification. This thesis reviews the technology roadmap up to and including current 3G systems LTE from the 3rd Generation Partnership Project (3GPP) and IEEE 802.16e-2005 from the Institute of Electrical and Electronics Engineers (IEEE). Furthermore, new requirements and features for LTE-Advanced and IEEE 802.16m as well as a comparative approach towards IMT-Advanced certification are presented. Finally, the thesis concludes with a discussion on the market status and deployment strategies of LTE and IEEE 802.16e-2005, or Mobile WiMAX as it is being marketed

Power allocation in carrier aggregation MIMO systems with different power constraints

The target set by the International Telecommunication Union (ITU) for the next generation of mobile communications, IMT-Advanced, is to achieve up to 1 Gb/s peak data rates. The 3rd Generation Partnership Project (3GPP) introduced Carrier Aggregation (CA) technology in its latest Long Term Evolution Advanced (LTE-Advanced) standards in order to meet the performance goals of the next generation, the fourth generation, 4G. The introduction of CA in LTE-Advanced system poses a challenge to the power control function of a CA-MIMO radio link. The problem appears when multiple Carrier Components (CCs), within a single or multiple frequency bands, are allocated to a user. The two challenges studied in this thesis are the different channel characteristics in the different CCs and the multiple power constraints imposed on the mobile equipment: per-CC, per-antenna and per-total transmit power available. This thesis studies the bit error rate (BER) performance of a CA-MIMO radio link with the Modified Hybrid Gradient Optimal Power Allocation (MHGOPA) algorithm. In order to examine the validity of the MHGOPA algorithm, the results are compared to a baseline uniform power allocation approach. The results of the simulations are obtained for different environments: Indoor Hotspot, Urban Microcell, Suburban Microcell and Urban Macrocell. The results show that the MHGOPA algorithm generally outperforms the baseline uniform power allocation when the channel conditions are good with typical SNR values above 8-10 dB, depending on the environment. The results also show a marginal improvement on the BER in some scenarios when relaxing the constraints on the antennas. The simulations also show that giving primary carrier components (PCC) a privilege in power results in a large degradation in overall performance