1. Introduction

2.Schematic and PCB Design

3.Experimental Results Show

4.Conclucion

Acknowledgement

References

In the process of news interviews, the last mile of data transmission from the reporter terminal to the system collection center has been using wired transmission. It has poor mobility and weak scalability. According to this situation, a hardware design based on the AR9341 wireless node is proposed. It makes full use of the advantages of better wireless transmission scalability and more flexible mobility. Firstly, its RF module is discussed in detail, and signal quality is ensured by Impedance Matching and Differential Routing. Secondly, its memory module is described, and the transmission performance of the system is analyzed through the eye diagram of the DDR signal lines. Finally, the Spectrum, Constellation and error vector magnitude (EVM) are measured by the spectrum analyzer to test the quality of the wireless signal and verify the feasibility of the design.

Introduction

News is an important way for us to obtain information from the outside world. Traditionally, the last mile of data transmission in the news interview relies on wired connections from reporter terminals to system collection centers. However, with the surge of global emergencies, the environment of news gathering has become complicated. The shortcomings of traditional wire connections are also increasing. Firstly, it has poor mobility. Cable is used as the main medium for wired transmission. You need to re-lay the cable if the interview environment changes, which is time-consuming and laborious. Secondly, the expansion is weak. If you add a new device, you need to re-route, when the port reserved by the original wiring is not enough.

Abstract

IEEE 802.11ax-2019 will replace both IEEE 802.11n-2009 and IEEE 802.11ac-2013 as the next high-throughput Wireless Local Area Network (WLAN) amendment. In this paper, we review the expected future WLAN scenarios and use-cases that justify the push for a new IEEE 802.11 amendment. Then, we overview a set of new technical features that may be included in this amendment and describe both their advantages and drawbacks. Finally, we discuss the list of network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other on-going IEEE 802.11 amendments such as the IEEE 802.11ai-2016, IEEE 802.11aq-2016 and IEEE 802.11ak-2017.

Introduction

IEEE 802.11 Wireless Local Area Networks (WLANs) [1] are a cost-efficient solution for wireless Internet access that can satisfy most current communication requirements in domestic, public and business scenarios.

Similar to other wireless technologies, WLANs have evolved by integrating the latest technological advances in the field as soon as they have become sufficiently mature. IEEE 802.11n-2009 adopted Single-user Multiple Input Multiple Output (SU-MIMO), channel bonding and packet aggregation. Those mechanisms were further extended in IEEE 802.11ac-2013, which also introduced Downlink Multi-user (MU) MIMO transmissions. These new features have improved the spectrum utilization efficiency and raw WLAN performance. In addition, new amendments such as the IEEE 802.11af-2013 and the IEEE 802.11ah-2017 are further expanding the application scenarios of WLANs, which include cognitive radio, long-range communication solutions, advanced power saving mechanisms, and support for Machine to Machine (M2M) devices.

مقاله سال 2016

A Novel Scheme For Optimizing Contention Window Adjustment in IEEE 802.11e Wireless Networks

شبکه محلی بی سیم 802.11 از کاربرد ترین مشخصه ها برای شبکه های wlan. 802.11 eاست که کارایی و قابلیت QoS آن را با اختصاص اولویت ها به انواع مختلف بسته داده افزایش داده است. روش بکار گرفته شده توسط 802.11e در مشخصه لایه ی MAC، مکانیزم دسترسی به کانال، شناخته شده به عنوان EDCF را تعیین می کند. رویکرد ثابت EDCF افزایش اندازه CW، بدون در نظر گرفتن شرایط کانال در عملکرد پایین در اندازه شبکه بالا نتیجه می دهد. مفهوم اساسی افزایش CW با توجه به مقیاس ثابت در خودش عدم انطباق پویای CW را با توجه به شرایط نشان می دهد. در این مقاله، ما یک تکنیک جدید جهت تعیین اندازه CW برای روش backoff معرفی می کنیم. FHCW مکانیسم پیشنهادی است که تاریخچه انتقالات قبلی را در نظر می گیرد و ابهام حاضر در کانال با توجه به عوامل مختلف از جمله تراکم، سنجش اعتبار ایستگاه کاری و اولویت بسته ارسال شود. مقایسه عملکرد هر دو تکنیک قابلیت طرح پیشنهادی را نشان می دهد.