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Modeling and Performance Analysis of CSMA-Based JCAS Networks

Navid Keshtiarast, Pradyumna Kumar Bishoyi, Marina Petrova

TL;DR

This paper addresses interference management in CSMA-based JCAS networks where sensing and communication share the same spectrum. It employs a stochastic-geometry framework with a homogeneous PPP to model node locations and a time-division scheme between radar and data slots, deriving closed-form expressions for radar performance via the maximum unambiguous range and for communication performance via throughput density, both depending on parameters such as $\lambda$, $M_r$, $M_c$, $\tau$, and $\eta$. Key contributions include a radar range expression under a false-alarm constraint $P_{fa}$ and a corresponding MAP $q_w$, plus a probability of successful reception $P_s$ and a throughput density $\mathcal{T}$, all validated by simulations. The results reveal a trade-off: increasing radar time improves sensing range but reduces throughput, especially in denser networks, guiding design choices for duty-cycle tuning and access schemes in future unlicensed JCAS deployments. The findings offer practical guidance for balancing sensing accuracy with communication efficiency in real-world sub-7 GHz JCAS systems.

Abstract

Joint communication and sensing (JCAS) networks are envisioned as a key enabler for a variety of applications which demand reliable wireless connectivity along with accurate and robust sensing capability. When sensing and communication share the same spectrum, the communication links in the JCAS networks experience interference from both sensing and communication signals. Therefore, it is crucial to analyze the interference caused by the uncoordinated transmission of either sensing or communication signals, so that effective interference mitigation techniques could be put in place. We consider a JCAS network consisting of dual-functional nodes operating in radar and communication modes. To gain access to the shared communication channel, each node follows carrier sense multiple access (CSMA)-based protocol. For this setting, we study the radar and communication performances defined in terms of maximum unambiguous range and aggregated network throughput, respectively. Leveraging on the stochastic geometry approach, we model the interference of the network and derive a closed-form expression for both radar and communication performance metrics. Finally, we verify our analytical results through extensive simulation.

Modeling and Performance Analysis of CSMA-Based JCAS Networks

TL;DR

This paper addresses interference management in CSMA-based JCAS networks where sensing and communication share the same spectrum. It employs a stochastic-geometry framework with a homogeneous PPP to model node locations and a time-division scheme between radar and data slots, deriving closed-form expressions for radar performance via the maximum unambiguous range and for communication performance via throughput density, both depending on parameters such as , , , , and . Key contributions include a radar range expression under a false-alarm constraint and a corresponding MAP , plus a probability of successful reception and a throughput density , all validated by simulations. The results reveal a trade-off: increasing radar time improves sensing range but reduces throughput, especially in denser networks, guiding design choices for duty-cycle tuning and access schemes in future unlicensed JCAS deployments. The findings offer practical guidance for balancing sensing accuracy with communication efficiency in real-world sub-7 GHz JCAS systems.

Abstract

Joint communication and sensing (JCAS) networks are envisioned as a key enabler for a variety of applications which demand reliable wireless connectivity along with accurate and robust sensing capability. When sensing and communication share the same spectrum, the communication links in the JCAS networks experience interference from both sensing and communication signals. Therefore, it is crucial to analyze the interference caused by the uncoordinated transmission of either sensing or communication signals, so that effective interference mitigation techniques could be put in place. We consider a JCAS network consisting of dual-functional nodes operating in radar and communication modes. To gain access to the shared communication channel, each node follows carrier sense multiple access (CSMA)-based protocol. For this setting, we study the radar and communication performances defined in terms of maximum unambiguous range and aggregated network throughput, respectively. Leveraging on the stochastic geometry approach, we model the interference of the network and derive a closed-form expression for both radar and communication performance metrics. Finally, we verify our analytical results through extensive simulation.
Paper Structure (11 sections, 1 theorem, 11 equations, 6 figures, 1 table)

This paper contains 11 sections, 1 theorem, 11 equations, 6 figures, 1 table.

Table of Contents

  1. Introduction
  2. System Model
  3. Radar Performance
  4. Communication Performance
  5. Channel model
  6. Channel access mechanism
  7. Probability of successful reception
  8. Performance Evaluation
  9. Setup and Scenarios
  10. Simulation Results and Discussion
  11. Conclusions

Key Result

Theorem 1

Given the desired false alarm probability ($P_{fa}$), the maximum unambiguous radar range is where $C(M_r,\epsilon,q_w)= 1-\frac{1}{M}-\sum_{i=M_r}^{M-1}{\frac{1}{M}(1-q_w)^{N_i}},$, $N_i = \min(M_r-1,M_r/\epsilon-i)$, and $q_w$ is the transmitting probability of the nodes in communication mode.

Figures (6)

  • Figure 1: System diagram of JCAS network
  • Figure 2: Time diagram of JCAS node over two cycles
  • Figure 3: Radar range vs. network density for different $\epsilon$
  • Figure 4: Throughput vs. network density for different $\tau$
  • Figure 5: Throughput vs. network density for different $\epsilon$
  • ...and 1 more figures

Theorems & Definitions (2)

  • Theorem 1
  • proof