# Emerging Topics in Joint Radio-Based Positioning, Sensing, and Communications
## 1 Introduction and Definitions
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Area** & **Search Keywords** & **CORE** & **Scopus** & \begin{tabular}{l} **Google** \\ **Scholar** \\ \end{tabular} & **MDPI** \\ \hline \multirow{3}{*}{Positioning} & \begin{tabular}{l} “wireless positioning” \\ \"radio localization\" \\ “wireless navigation\" \\ \end{tabular} & 1153 & 3360 & 9000 & 58 \\  & \begin{tabular}{l} “radio localization” \\ “wireless navigation” \\ \end{tabular} & 662 & 1789 & 3600 & 24 \\ \hline \multirow{3}{*}{Sensing} & \begin{tabular}{l} “wireless sensing” \\ “radar” \\ \end{tabular} & 5357 & 16,038 & 45,100 & 255 \\  & \begin{tabular}{l} “radar” \\ \end{tabular} & 507,727 & 789,674 & 4,780,000 & 11,956 \\ \hline \multirow{3}{*}{Communications} & \begin{tabular}{l} “wireless communications” \\ “radio communications” \\ \end{tabular} & 114,657 & 830,169 & 1,160,000 & 3196 \\  & \begin{tabular}{l} “radio communications” \\ \end{tabular} & 28,624 & 139,957 & 287,000 & 226 \\  & \begin{tabular}{l} “telecommunications” \\ \end{tabular} & 446,714 & 1,586,347 & 3,500,000 & 10,093 \\ \hline \multirow{2}{*}{ISAC} & \begin{tabular}{l} “JSAC” \\ “JSAC” \\ \end{tabular} & 9498 & 16,279 & 59,700 & 2 \\  & \begin{tabular}{l} “JSAC” \\ “radio SLAM” \\ \end{tabular} & 24,192 & 11,354 & 172,000 & 441 \\ \hline \multirow{2}{*}{SLAM} & \
\begin{tabular}{l} “SLAM” \\ “radio SLAM” \\ \end{tabular} & 120,114 & 64,035 & 738,000 & 1213 \\  &
\begin{tabular}{l} “radio SLAM” \\ \end{tabular} & 77 & 199 & 329 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Examples of the number of citations in five selected research areas related to positioning, sensing, and communications (as of 10 January 2025). Figure 2: An illustration of the benefits of JPSAC solutions for various application areas (figure partially created with the Copilot Designer AI tool). Brief State-of-the-Art Overview on Research Addressing Joint Radio-Based Communication, Sensing, and Positioning Aspects  
The research on joint radio-based communications, sensing, and positioning is a fast evolving field, driven by the need to efficiently utilize the radio spectrum and to enhance the capabilities of modern wireless systems. The problems associated with JPSAC are typically complex optimization problems aiming to optimize the use of available resources such as bandwidth and power and to enable simultaneous data transmission, environmental sensing, and precise positioning. The main sub-research areas included under the wide JPSAC umbrella are:  
* A waveform design to reach the desired JPSAC targets (see the discussion of typical performance metrics below) [28; 37; 38]
* Channel modeling and estimation under various scenarios (e.g., far-field and near-field, Multiple Inputs-Multiple Outputs (MIMO), massive Multiple Inputs-Multiple Outputs (mMIMO), and ultra-massive Multiple Inputs-Multiple Outputs (umMIMO), etc.) [25; 29; 34; 36]
* Optimal resource allocation and management (e.g., beamforming strategies, power control, spectrum allocation, etc.) [15; 39]
* Robust estimators and filtering for radio SLAM approaches [31; 32; 34; 35; 40]  
The envisaged advantages of a ISAC, SLAM, or in general, of any JPSAC-related solution of integrating two or more of the three areas (communication, sensing, and positioning) are:  
* An improved Spectral Efficiency (SE) compared to systems focusing on only one of the three areas (communication, sensing, and positioning);
* A reduction in device size, cost, and complexity with same quality of service or performance as the non-joint solutions;
* Decreased power consumption, especially at the mobile device side;
* Increased capacity or throughputs with lower Bit Error Rate (BER);
* Better use of existing resources (e.g., time, space, and frequency resources).