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Integrated Sensing and Communication with Nested Array: Beam Pattern and Performance Analysis

Hongqi Min, Chao Feng, Ruoguang Li, Yong Zeng

TL;DR

This work investigates integrated sensing and communication (ISAC) using a two-level nested array at the base station to enlarge aperture without increasing physical antennas. It derives closed-form beam-pattern metrics—main-lobe beam width (BW), peak-to-local-minimum ratio (PLMR), and dominating side lobes height (SLH)—and analyzes how the array configuration $(N_1,N_2)$ and user distribution affect ISAC performance. Numerical results for uplink ISAC show that nested arrays can achieve higher data rates for densely located users while preserving sensing performance, and sensing-first configurations can further enhance sensing without sacrificing communication. The findings provide practical guidance for designing sparse, wide-aperture arrays in 6G ISAC systems and highlight the trade-offs between main-lobe width and side-lobe interference mitigation.

Abstract

Towards the upcoming 6G wireless networks, integrated sensing and communication (ISAC) has been identified as one of the typical usage scenarios. To further enhance the performance of ISAC, increasing the number of antennas as well as array aperture is one of the effective approaches. However, simply increasing the number of antennas will increase the cost of radio frequency chains and power consumption. To address this issue, in this paper, we consider an uplink ISAC system with nested array deployed at the base station. Nested array is a classic sparse array architecture that is able to enlarge the array aperture without increasing the number of physical antennas. While nested array for wireless sensing has been extensively studied, its potential for ISAC system has not been fully exploited. To fill this gap, in this paper, we provide the beam pattern analysis of nested arrays, and derive the closed-form expressions for the three beam pattern metrics, namely, the main lobe beam width, peak-to-local-minimum ratio, and prominent side lobes height. Extensive simulation results are provided to show that compared with conventional uniform arrays, nested arrays can achieve higher communication performance for densely located users while maintaining its advantage of sensing.

Integrated Sensing and Communication with Nested Array: Beam Pattern and Performance Analysis

TL;DR

This work investigates integrated sensing and communication (ISAC) using a two-level nested array at the base station to enlarge aperture without increasing physical antennas. It derives closed-form beam-pattern metrics—main-lobe beam width (BW), peak-to-local-minimum ratio (PLMR), and dominating side lobes height (SLH)—and analyzes how the array configuration and user distribution affect ISAC performance. Numerical results for uplink ISAC show that nested arrays can achieve higher data rates for densely located users while preserving sensing performance, and sensing-first configurations can further enhance sensing without sacrificing communication. The findings provide practical guidance for designing sparse, wide-aperture arrays in 6G ISAC systems and highlight the trade-offs between main-lobe width and side-lobe interference mitigation.

Abstract

Towards the upcoming 6G wireless networks, integrated sensing and communication (ISAC) has been identified as one of the typical usage scenarios. To further enhance the performance of ISAC, increasing the number of antennas as well as array aperture is one of the effective approaches. However, simply increasing the number of antennas will increase the cost of radio frequency chains and power consumption. To address this issue, in this paper, we consider an uplink ISAC system with nested array deployed at the base station. Nested array is a classic sparse array architecture that is able to enlarge the array aperture without increasing the number of physical antennas. While nested array for wireless sensing has been extensively studied, its potential for ISAC system has not been fully exploited. To fill this gap, in this paper, we provide the beam pattern analysis of nested arrays, and derive the closed-form expressions for the three beam pattern metrics, namely, the main lobe beam width, peak-to-local-minimum ratio, and prominent side lobes height. Extensive simulation results are provided to show that compared with conventional uniform arrays, nested arrays can achieve higher communication performance for densely located users while maintaining its advantage of sensing.
Paper Structure (15 sections, 16 equations, 6 figures)

This paper contains 15 sections, 16 equations, 6 figures.

Table of Contents

  1. Introduction
  2. System Model and Signal Processing
  3. System Model
  4. Communication Signal Processing
  5. Localization Signal Processing
  6. Beam Pattern of Nested Array
  7. Main lobe Beam Width (BW)
  8. Peak-to-Local-Minimum Ratio (PLMR)
  9. Prominent Side Lobe Height (SLH)
  10. Numerical Results
  11. Conclusions
  12. Proof of Theorem \ref{['wuyulin']}
  13. $N_2>N_{ap}$
  14. $N_{th}< N_2\leq N_{ap}$
  15. $2\leq N_2\leq N_{th}$

Figures (6)

  • Figure 1: Uplink ISAC system with nested array deployed at the BS.
  • Figure 2: Beam pattern of nested array with $\left(N_1,N_2\right)=\left(8,8\right)$.
  • Figure 3: RMSE and data rate v.s. $N_1$.
  • Figure 4: Data rate v.s. $M$.
  • Figure 5: RMSE and data rate v.s. $M$.
  • ...and 1 more figures

Theorems & Definitions (3)

  • Definition 1
  • Definition 2
  • Definition 3