In this talk, the tradeoff between energy efficiency and spectral efficiency in multicell heterogeneous networks is investigated. Our objective is to maximize both energy efficiency and spectral efficiency of the network, while satisfying the minimum rate requirements of the users. We define our objective function as the weighted summation of energy efficiency and spectral efficiency functions. The fractional frequency reuse (FFR) scheme is employed to suppress intercell interference. We formulate the problem as cell-center boundary selection for FFR, frequency assignment to users, and power allocation. The optimal solution to this problem requires exhaustive search over all cell-center radii, frequency assignments, and power levels. We propose a three-stage algorithm and apply it consecutively until convergence. First, we select the cell-center radius for the FFR method. Second, we assign the frequency resources to users to satisfy their rate requirements and maximize the objective function. Third, we solve the power allocation subproblem by using the Levenberg-Marquardt method. Minimum rate requirements of users are also included in the solution by using dual decomposition techniques. Our numerical results show a Pareto-optimal solution for energy efficiency and spectral efficiency. We present energy efficiency, spectral efficiency, outage probability, and average transmit power results for different minimum rate constraints. Among other results, we show that, in a particular setting, 13% energy efficiency increase can be obtained in a multicell heterogeneous wireless network by sacrificing 7% spectral efficiency. Speaker(s): Ender Ayanoglu , Virtual: https://events.vtools.ieee.org/m/466455

We are pleased to welcome Dr. Keith A. Bowman, Principal Engineer at Qualcomm Technologies, Inc., as our Distinguished Lecturer. Dr. Bowman will be speaking at BYU on the topic of "Adaptive Designs for Processor Performance, Energy Efficiency, and Reliability". Keith brings a wealth of industry experience on this topic pertaining to today's cutting edge IC design. System-on-chip (SoC) processors are used across a wide range of market segments, including Internet of Things (IoT), mobile, laptop, automotive, and datacenter, experience dynamic device, circuit, and system parameter variations during the operational lifetime. These dynamic parameter variations include supply voltage droops, temperature changes, transistor aging, and workload fluctuations, degrade processor performance, energy efficiency, yield, and reliability. This lecture introduces the primary variation sources and the negative impact of these variations across voltage and clock frequency operating conditions. Dr. Bowman will also present adaptive processor designs to mitigate the adverse effects from dynamic parameter variations, while highlighting the key trade-offs and considerations for product deployment. Additionally, Dr. Bowman will provide a follow up lecture entitled, "How to Write a Strong SSCS Paper" for those that are interested. This event requires pre-registration by March 12, 2025. Co-sponsored by: Brigham Young University College of Engineering Speaker(s): Keith Bowman, Agenda: Dr. Bowman's lecture will start promptly at 10:00am MST in the BYU Engineering Building (EB) Event Space. A Question and Answer session will follow. A pizza lunch will be provided from 12pm to 1:00pm. Lunch is free for IEEE members, with a $6.00 charge for non-members. A special follow up lecture and Question and Answer session will begin at 1:00pm in Room CB 490, in which Dr. Bowman will discuss, “How to Write a Strong SSCS Paper." This will last approximately 1 hour. Room: Event Space, Bldg: Engineering Building, Brigham Young University, Campus Dr, Provo, Utah, United States, 84604

Voiceband modems convert a stream of digital symbols into audible signals and transmit them over the Public Switched Telephone Network (PSTN). The first voiceband modem was developed in 1958 and operated at 110 bits/s. Being subject to international standards developed by the International Union of Telecommunications, Telecommunication Standardization Sector (ITU-T), a body of the United Nations, these modems consistently increased their transmission speeds within the next several decades. Every step in the standards process involved a major development in signal processing and communications, such as various forms of adaptive equalization, echo cancellation, and trellis coded modulation. These contributions approximately doubled the transmission speed of every step of the standardization process, starting with 300 b/s in 1962 until about 28.8-33.6 kb/s in 1996. Modem designers invoked Shannon's capacity formula and, considering quantization noise occurring at the Analog-to-Digital conversion process in the PSTN Central Office as additive white Gaussian noise, decided that the channel capacity for such modems is about 36 kb/s. Yet, towards the end of 1990s, modems that operated at transmission speeds close to 56 kb/s, known generally as 56K modems appeared. This talk will first give a brief history of voiceband modems, and it will describe how it was possible to beat the Shannon capacity formula with the 56K modems. The underlying modeling process and the related mathematics will be described. A history of the development of the 56K modems will be presented and, looking back several decades, the technological, as well as the economic and social impact of these modems, will be discussed. Speaker(s): Ender Ayanoglu, Virtual: https://events.vtools.ieee.org/m/466459