This book addresses two aspects of network operation quality; namely, resource management and fault management. Network operation quality is among the functions to be fulfilled in order to offer quality of service, QoS, to the end user. It is characterized by four parameters: – packet loss; – delay; – jitter, or the variation of delay over time; – availability. Resource management employs mechanisms that enable the first three parameters to be guaranteed or optimized. Fault management aims to ensure continuity of service.
標簽： Ethernet Networks MPLS and IP
上傳時間： 2020-05-27
上傳用戶：shancjb
Quality of Service ( QoS ) has always been in a world of its own, but as the technology has been refi ned and has evolved in recent years, QOS usage has increased to the point where it is now considered a necessary part of network design and operation. As with most technologies, large - scale deployments have led to the technology becoming more mature, and QOS is no exception.
標簽： QOS-Enabled Networks
上傳時間： 2020-05-31
上傳用戶：shancjb
It was only a few years ago that “ubiquitous connectivity” was recognized as the future of wireless communication systems. In the era of ubiquitous connectivity, it was expected that the broadband mobile Internet experience would be pervasive, and seamless connectivity on a global scale would be no surprise at all. The quality of service would be guaranteed no matter when/where/what the users wanted with the connectivity. Connectivity would even be extended to object-to-object communication, where no human intervention was required. All objects would become capable of autonomous communication.
標簽： Protocols Radio LTE-A LTE for and
上傳時間： 2020-06-01
上傳用戶：shancjb
Driven by the desire to boost the quality of service of wireless systems closer to that afforded by wireline systems, space-time processing for multiple-input multiple-output (MIMO) wireless communications research has drawn remarkable interest in recent years. Excit- ing theoretical advances, complemented by rapid transition of research results to industry products and services, have created a vibrant and growing area that is already established by all counts. This offers a good opportunity to reflect on key developments in the area during the past decade and also outline emerging trends.
標簽： Space-Time Processing
上傳時間： 2020-06-01
上傳用戶：shancjb
Fourth Generation (4G) wireless communication systems aim to allow peak data rates in the range of 1 Gbps for nomadic access and 100 Mbps for vehicular mobil- ity. 4G aims to support current and emergent multimedia services, such as mobile TV, social networks and gaming, high-definition television and video telecon- ference, multimedia messaging service, using the All-over IP concept and with improved quality of service.
標簽： Transmission Techniques Systems for 4G
上傳時間： 2020-06-01
上傳用戶：shancjb
Having dealt with in-depth analysis of SS#7, GSM and GPRS networks I started to monitor UTRAN interfaces approximately four years ago. Monitoring interfaces means decoding the data captured on the links and analysing how the different data segments and messages are related to each other. In general I wanted to trace all messages belonging to a single call to prove if the network elements and protocol entities involved worked fine or if there had been failures or if any kind of suspicious events had influenced the normal call proceeding or the call’s quality of service. Cases showing normal network behaviour have been documented in Kreher and Ruedebusch (UMTS Signaling. John Wiley & Sons, Ltd, 2005), which provides examples for technical experts investigating call flows and network procedures.
標簽： Performance Measurement Practical Guide UMTS
上傳時間： 2020-06-01
上傳用戶：shancjb
Mobile radio communications are evolving from pure telephony systems to multimedia platforms offering a variety of services ranging from simple file transfers and audio and video streaming, to interactive applications and positioning tasks. Naturally, these services have different constraints concerning data rate, delay, and reliability (quality-of-service (QoS)). Hence, future mobile radio systems have to provide a large flexibility and scal- ability to match these heterogeneous requirements.
標簽： Communications Wireless Channels MIMO over
上傳時間： 2020-06-01
上傳用戶：shancjb
1. 目的 規范產品的PCB焊盤設計工藝， 規定PCB焊盤設計工藝的相關參數，使得PCB 的設計滿足可生產性、可測試性、安規、EMC、EMI 等的技術規范要求,在產品設計過程中構建產品的工藝、技術、質量、成本優勢。 2. 適用范圍本規范適用于空調類電子產品的PCB 工藝設計，運用于但不限于PCB 的設計、PCB 批產工藝審查、單板工藝審查等活動。本規范之前的相關標準、規范的內容如與本規范的規定相抵觸的，以本規范為準3.引用/參考標準或資料TS-S0902010001 <〈信息技術設備PCB 安規設計規范〉>TS—SOE0199001 <〈電子設備的強迫風冷熱設計規范〉〉TS—SOE0199002 〈<電子設備的自然冷卻熱設計規范>>IEC60194 〈<印制板設計、制造與組裝術語與定義>> （Printed Circuit Board designmanufacture and assembly-terms and definitions)IPC—A-600F 〈<印制板的驗收條件>〉 （Acceptably of printed board)IEC609504。規范內容4。1焊盤的定義 通孔焊盤的外層形狀通常為圓形、方形或橢圓形。具體尺寸定義詳述如下，名詞定義如圖所示。1) 孔徑尺寸:若實物管腳為圓形：孔徑尺寸(直徑)=實際管腳直徑+0。20∽0。30mm（8。0∽12。0MIL）左右；若實物管腳為方形或矩形：孔徑尺寸（直徑）=實際管腳對角線的尺寸+0.10∽0。20mm（4.0∽8。0MIL）左右。2) 焊盤尺寸： 常規焊盤尺寸=孔徑尺寸（直徑)+0.50mm（20.0 MIL)左右.…………
標簽： PCB
上傳時間： 2022-05-24
上傳用戶：canderile
特點： 精確度0.1%滿刻度 可作各式數學演算式功能如:A+B/A-B/AxB/A/B/A&B(Hi or Lo)/|A|/ 16 BIT類比輸出功能 輸入與輸出絕緣耐壓2仟伏特/1分鐘(input/output/power) 寬范圍交直流兩用電源設計 尺寸小,穩定性高
上傳時間： 2014-12-23
上傳用戶：ydd3625
開關在電路中起接通信號或斷開信號的作用。最常見的可控開關是繼電器，當給驅動繼電器的驅動電路加高電平或低電平時，繼電器就吸合或釋放，其觸點接通或斷開電路。CMOS模擬開關是一種可控開關，它不象繼電器那樣可以用在大電流、高電壓場合，只適于處理幅度不超過其工作電壓、電流較小的模擬或數字信號。 一、常用CMOS模擬開關引腳功能和工作原理 1.四雙向模擬開關CD4066 CD4066 的引腳功能如圖1所示。每個封裝內部有4個獨立的模擬開關，每個模擬開關有輸入、輸出、控制三個端子，其中輸入端和輸出端可互換。當控制端加高電平時，開關導通；當控制端加低電平時開關截止。模擬開關導通時，導通電阻為幾十歐姆；模擬開關截止時，呈現很高的阻抗，可以看成為開路。模擬開關可傳輸數字信號和模擬信號，可傳輸的模擬信號的上限頻率為40MHz。各開關間的串擾很小，典型值為－50dB。
上傳時間： 2013-10-27
上傳用戶：bibirnovis
