Effective interference level-based packet transmission for multiple-input multiple-output systems with hybrid automatic repeat request

2015 ◽  
Vol 9 (18) ◽  
pp. 2208-2215
Author(s):  
Younghoon Whang ◽  
Huaping Liu ◽  
Sangjoon Park
Author(s):  
Le Ty Khanh ◽  
Ha Hoang Kha ◽  
Nguyen Minh Hoang

This paper is concerned with a multiple-input multiple-output (MIMO) multi-user wireless networks in which multiple secondary users (SUs) can share the same radio spectrum with a single primary user (PU). The design problems of the transceivers in such MIMO interference channels are to find the precoding matrices at the transmitters and the receiving matrices at the receivers to minimize the mean square error (MSE) or to maximize the sum-rate of the SUs while guaranteeing the interference power at the PU receiver below an acceptable threshold. In this paper, we consider to design the transceivers using the interference alignment techniques. The objective is to align the interference at the SUs and maintain an acceptable leakage interference level from the SUs into the signal subspace of the PU receiver. Due to the nonlinearity and nonconvexity of the underlaying problems, we develop an alternating algorithm which efficiently solves a convex optimization in each iteration. The numerical results are provided to validate the performance of our algorithm.


2012 ◽  
Vol 229-231 ◽  
pp. 1414-1418
Author(s):  
Cong Cong Li ◽  
Jun Li ◽  
Chao Hai Li ◽  
Wen Jun Huang

The performance of a Ground Moving Target Indication (GMTI) radar is determined by the interference level of the clutter to a large extent. With the longer illumination and the larger aperture, Multiple-Input, Multiple-Output (MIMO) radar greatly enhances the ability to detect the slow-moving target. This paper compares MIMO radar with conventional phased-array radar in terms of signal to clutter and noise ratio (SCNR) performance. Moreover, the paper proves the fact that the improvement of SCNR with MIMO techniques is not only limited in the antenna configuration of the side-looking but also non-sidelooking array-antenna. The analysis of mianlobe clutter and sidelobe clutter levels can greatly simplify the computation of the total clutter. Finally, the experimental simulation is been given.


2021 ◽  
Author(s):  
Jie Ding ◽  
Mahyar Nemati ◽  
Shiva Pokhrel ◽  
Ok-Sun Park ◽  
Jinho Choi ◽  
...  

<div>Enabling ultra-reliable low-latency communication (URLLC) with stringent requirements for transmitting data packets (e.g., 99.999% reliability and 1 millisecond latency) presents considerable challenges in uplink transmissions. For each packet transmission over dynamically allocated network radio resources, the conventional random access protocols are based on a request- rant scheme. This induces excessive latency and necessitates reliable control signalling, resulting overhead. To address these problems, grant-free (GF) solutions are proposed in the fifth-generation (5G) new radio (NR). In this paper, an overview and vision of the state-of-the-art in enabling GF URLLC are presented. In particular, we first provide a comprehensive review of NR specifications and techniques for URLLC, discuss underlying principles, and highlight impeding issues of enabling GF URLLC. Furthermore, we explain two key phenomena of massive multiple-input multiple-output (mMIMO) (i.e., channel hardening and favorable propagation) and build several deep insights into how celebrated mMIMO features can be exploited to enhance the performance of GF URLLC. Moving further ahead, we examine the potential of cell-free (CF) mMIMO and analyze its distinctive features and benefits over mMIMO to resolve GF URLLC issues. Finally, we identify future research directions and challenges in enabling GF URLLC with CF mMIMO.</div>


2021 ◽  
Author(s):  
Jie Ding ◽  
Mahyar Nemati ◽  
Shiva Pokhrel ◽  
Ok-Sun Park ◽  
Jinho Choi ◽  
...  

<div>Enabling ultra-reliable low-latency communication (URLLC) with stringent requirements for transmitting data packets (e.g., 99.999% reliability and 1 millisecond latency) presents considerable challenges in uplink transmissions. For each packet transmission over dynamically allocated network radio resources, the conventional random access protocols are based on a request- rant scheme. This induces excessive latency and necessitates reliable control signalling, resulting overhead. To address these problems, grant-free (GF) solutions are proposed in the fifth-generation (5G) new radio (NR). In this paper, an overview and vision of the state-of-the-art in enabling GF URLLC are presented. In particular, we first provide a comprehensive review of NR specifications and techniques for URLLC, discuss underlying principles, and highlight impeding issues of enabling GF URLLC. Furthermore, we explain two key phenomena of massive multiple-input multiple-output (mMIMO) (i.e., channel hardening and favorable propagation) and build several deep insights into how celebrated mMIMO features can be exploited to enhance the performance of GF URLLC. Moving further ahead, we examine the potential of cell-free (CF) mMIMO and analyze its distinctive features and benefits over mMIMO to resolve GF URLLC issues. Finally, we identify future research directions and challenges in enabling GF URLLC with CF mMIMO.</div>


Sign in / Sign up

Export Citation Format

Share Document