arXiv subjects

Dan Keun Sung

Publications and source records attributed to Dan Keun Sung.

5 recordsLinked to original sources

arXiv2026

Efficient Local-to-Global Collaborative Perception via Joint Communication and Computation Optimization

Autonomous driving relies on accurate perception to ensure safe driving. Collaborative perception improves accuracy by mitigating the sensing limitations of individual vehicles, such as limited perception range and occlusion-induced blind spots. However, collaborative perception often suffers from high communication overhead due to redundant data transmission, as well as increasing computation latency caused by excessive load with growing connected and autonomous vehicles (CAVs) participation. To address these challenges, we propose a novel local-to-global collaborative perception framework (LGCP) to achieve collaboration in a communication- and computation-efficient manner. The road of interest is partitioned into non-overlapping areas, each of which is assigned a dedicated CAV group to perform localized perception. A designated leader in each group collects and fuses perception data from its members, and uploads the perception result to the roadside unit (RSU), establishing a link between local perception and global awareness. The RSU aggregates perception results from all groups and broadcasts a global view to all CAVs. LGCP employs a centralized scheduling strategy via the RSU, which assigns CAV groups to each area, schedules their transmissions, aggregates area-level local perception results, and propagates the global view to all CAVs. Experimental results demonstrate that the proposed LGCP framework achieves an average 44 times reduction in the amount of data transmission, while maintaining or even improving the overall collaborative performance.

cs.DC↗

arXiv2017

An Enhanced Access Reservation Protocol with a Partial Preamble Transmission Mechanism in NB-IoT Systems

In this letter, we propose an enhanced Access Reservation Protocol (ARP) with a partial preamble transmission (PPT) mechanism for the narrow band Internet of Things (NB-IoT) systems. The proposed ARP can enhance the ARP performance by mitigating the occurrence of preamble collisions, while being compatible with the conventional NB-IoT ARP. We provide an analytical model that captures the performance of the proposed ARP in terms of false alarm, mis-detection and collision probabilities. Moreover, we investigate a trade-off between the mis-detection and the collision probabilities, and optimize the proposed ARP according to the system loads. The results show that the proposed ARP outperforms the conventional NB-IoT ARP, in particular at heavier system loads.

cs.IT↗

arXiv2017

A Preamble Collision Resolution Scheme via Tagged Preambles for Cellular IoT/M2M Communications

In this paper, we propose a preamble (PA) collision resolution (PACR) scheme based on multiple timing advance (TA) values captured via tagged PAs. In the proposed PACR scheme, tags are embedded in random access (RA) PAs and multiple TA values are captured for a single detected PA during a tag detection procedure. The proposed PACR scheme significantly improves RA success probability for stationary machine nodes since the nodes using collided PAs can successfully complete the corresponding RAs using exclusive data resource blocks.

cs.IT↗

arXiv2015

Joint Link Adaptation and User Scheduling with HARQ in Multi-Cell Environments

Inter-cell interference (ICI) is one of the most critical factors affecting performance of cellular networks. In this paper, we investigate a joint link adaptation and user scheduling problem for multi-cell downlink employing HARQ techniques, where the ICI exists among cells. We first propose an approximation method on aggregated ICI for analyzing an effective signal-to-interference-and-noise ratio (SINR) with the HARQ technique at users, named identical path-loss approximation (IPLA). Based on the proposed IPLA, we propose a transmission rate selection algorithm maximizing an expected throughput at each user. We also propose a simple but effective cross-layer framework jointly combining transmission rate adaptation and user scheduling techniques, considering both HARQ and ICI. It is shown that statistical distribution of the effective SINR at users based on the IPLA agrees well with the empirical distribution, while the conventional Gaussian approximation (GA) does not work well in the case that dominant ICIs exist. Thus, IPLA enables base stations to choose more accurate transmission rates. Furthermore, the proposed IPLA-based cross-layer policy outperforms existing policies in terms of both system throughput and user fairness.

cs.IT↗

arXiv2015

Variable-Length Feedback Codes under a Strict Delay Constraint

We study variable-length feedback (VLF) codes under a strict delay constraint to maximize their average transmission rate (ATR) in a discrete memoryless channel (DMC) while considering periodic decoding attempts. We first derive a lower bound on the maximum achievable ATR, and confirm that the VLF code can outperform non-feedback codes with a larger delay constraint. We show that for a given decoding period, as the strict delay constraint, L, increases, the gap between the ATR of the VLF code and the DMC capacity scales at most on the order of O(L^{-1}) instead of O(L^{-1/2}) for non-feedback codes as shown in Polyanskiy et al. ["Channel coding rate in the finite blocklengh regime," IEEE Trans. Inf. Theory, vol. 56, no. 5, pp. 2307-2359, May 2010.]. We also develop an approximation indicating that, for a given L, the achievable ATR increases as the decoding period decreases.

cs.IT↗