11b g e pervasive and mobile networks

... Whenever the frame received well by the recipient, the latter will send an acknowledgement (ACK) message to the sender If the WLAN station does not receive the ACK, it deduces that there were a ... Wireless and Mobile Network Security context has changed from wired to wireless networks, we are facing the same issues and challenges regarding security More precisely, it is about preserving ... features needed to reserve battery life The connectivity from the wireless MT device to the BS will be automatic and transparent to the user 1.3.6 MIH: IEEE 802.21 IEEE 802.21 is an emerging IEEE...

Ngày tải lên: 16/02/2014, 15:20

... grouped into three categories: • • • Concepts, Trends, and Challenges: Entries under this category deal with the fundamental and emerging concepts related to e- commerce, e- government, and mobile ... Encyclopedia of E- Commerce, EGovernment, and Mobile Commerce Subsequently, the two-volume Encyclopedia of E- Commerce, E- Government, and Mobile Commerce includes more than 200 entries highlighting current ... the item list has been determined, a proper space element is selected from the content database (one with enough placeholders for the selected items and matching the user preferences), and the...

Ngày tải lên: 01/06/2014, 09:15

... to reduce the intercell interference which unfortunately lies outside the responsibility of the serving cell Even more severe, the neighbors can only decrease interference by degrading their ... LAPC the CDF is steeper since the users spread their data rate over a larger bandwidth leaving less PRBs unused (without interference) and leading to a smoother interference The interference of ... the user throughputs according to (27) is given in Figure As expected we observe slightly higher user throughputs with the larger P0 value However, the difference between the curves is smaller...

Ngày tải lên: 21/06/2014, 11:20

... động xoá đăng ký với foreign agent rời khỏi foreign network • giao thức đăng ký foreign-agent-to-home-agent ,foreign agent sẽđăng ký COA nút di động với homee agent Một foreign agent không cầnxoá ... thừa hưởng (IPv4) công nghệ mạng Internet Có hai loại nút lõi mạng 3G: Serving GPRS Support Nút (SGSNs) Gateway GPRS Support Node (GGSNs) (GPRS viết tắt Generalized Packet Radio Service, dịch ... nối nhiều SGSNs vào Internet lớn Do A GGSN phần cuối sở hạ tầng 3G mà g i tin có nguồn g c nút di động g p trước vào Internet lớn Đối với giới bên ngoài, GGSN trông giống router gateway khác;...

Ngày tải lên: 20/11/2015, 17:54

... presented in a highly readable manner, providing a great all-inclusive source for learning and references on the subject of 3G wireless technology I hope every reader enjoys and takes advantage ... systems provided three types of mobile telephone service: I Complete Mobile Telephone Service (MTS) for voice communication to land -mobile users assisted with mobile telephone operators where necessary ... system are presented The treatment of topics is neither too detailed nor too brief, and our expectation is that a wide spectrum of readers— systems engineers, engineering managers, people who are...

Ngày tải lên: 02/03/2013, 16:58

... presented in a highly readable manner, providing a great all-inclusive source for learning and references on the subject of 3G wireless technology I hope every reader enjoys and takes advantage ... systems provided three types of mobile telephone service: I Complete Mobile Telephone Service (MTS) for voice communication to land -mobile users assisted with mobile telephone operators where necessary ... system are presented The treatment of topics is neither too detailed nor too brief, and our expectation is that a wide spectrum of readers— systems engineers, engineering managers, people who are...

Ngày tải lên: 23/12/2013, 01:17

... more With a comprehensive monitoring system as discussed above, however, we have been able to detect most of these problems and reconfigure the measurement infrastructure where required Readers ... the same device and AP configuration, there was a large variation in handoff latency, and the higher the latency, the higher the standard deviation Some of the differences in latency between devices ... be interesting to see how these perform with traces of newer, more mobile, clients Wireless sniffing is still a new area, and one that presents many challenges The studies that have used wireless...

Ngày tải lên: 20/01/2014, 01:21

... wireless technologies empowering a wide spectrum of personal to enterprise applications and services, research and development in the related areas has experienced a very healthy growth since the early ... sensor networks And surely, once the reader goes through some of the chapters, she will want to explore deeper the subjects covered and the issues addressed in the book These include performance analysis, ... home design, and ‘‘on-demand business’’ in the context of pervasive computing The objective of the book is twofold: to bridge the gap between practice and theory and between different types of...

Ngày tải lên: 20/01/2014, 01:21

... amplitude falls below a given level with respect to its average value, we say that the mobile has gone into a fade Chapter 42 Received Signal Envelope Figure 2-6 A Rayleigh fading signal The figure ... and receiving antenna gains with regard to an isotropic antenna, and l is the wavelength of the signal frequency The term within the parentheses is the effective aperture of the receiving antenna ... moving vehicle experiences a rapidly fluctuating signal The rate at which the received signal crosses the fades depends upon the mobile velocity, the RF carrier wavelength, and the depth of the...

Ngày tải lên: 18/06/2014, 10:05

... decoder Alternatively, the decoder may read the analog samples of the matched filter, and based on certain rules that are designed to optimize the performance of the receiver, determine the received ... decision decoding improves the bit error rate performance of the receiver Generally, the higher the quantization levels, the greater this improvement With eight levels, there is a gain of about ... scrambling codes These codes are generated by a multibit shift register, where some selected outputs are added modulo and fed back to the input The underlying theory is well documented in the literature...

Ngày tải lên: 18/06/2014, 10:05

... performance of the receiver depends on the accuracy with which the strongest interference is detected in the first stage, reference [24] suggests using a multipath-combining receiver for detecting the ... receiver structures where these computational requirements are less stringent Another technique suggested for multiuser detection involves successive cancellation of interference from the received ... as well as messages directed to mobile stations such as a general page message, alert, abbreviated alert, release, reorder, and so on The information rate on a paging channel may be either 9.6...

Ngày tải lên: 18/06/2014, 10:05

... and voice messaging where a calling party can leave a voice message that can be retrieved later by the called party I Bearer services These include data services and short messaging services For ... called GPRS A number of references are available in the literature that describe the GSM system in great detail See, for example, [23], [1], and [2] Reference [9] gives a detailed description of GPRS ... all mobile stations that are registered Each mobile is assigned a unique IMEI number that can be used to determine whether the equipment is genuine or not The OMC is a centralized network management...

Ngày tải lên: 18/06/2014, 10:05

... Architecture Figure 5-13 is the architecture of a general GPRS network The interface points between different elements of the network have also been indicated To see the difference between a GSM and ... system-wide reference time scale However, each cell or each sector of a cell must now use a different scrambling code Because there is no global timing reference, the time offsets between signals ... over the air interface are segmented at the SNDCP layer into smaller packets and passed to the LLC layer where a header and The GSM System and General Packet Radio Service (GPRS) Header + User...

Ngày tải lên: 18/06/2014, 10:05

... the acknowledged transfer mode, the receiving RLC entity reassembles the received segments and delivers a unique copy of each PDU to the higher layers in the correct sequence Outof-sequence packets ... that have changed in the meantime The receiving end saves the full header and uses it to decompress the received header If, however, the entire header changes at some point, it will be necessary ... longer the best one) They are evaluated and filtered at different layers before they are reported to the higher layers These measurements are done during idle slots inserted in a radio frame for...

Ngày tải lên: 18/06/2014, 10:05

... HLR Gd Gb Gs SGSN Gn Gr SGSN To other SGSN Gp Another PLMN Gc Gn Gi GGSN GGSN oo To other PDNs PDN1 (e .g The Internet) Gi PDN2 3G Network The 3G UMTS network architecture was shown in Figure 6-2 ... UTRAN and sends an acknowledgement back The messages exchanged when the active set is to be updated are shown in Figure 6-35 Figure 6-34 Intercell handover In this case, all cells have the same W-CDMA ... first we will review the 3G system requirements so that we can understand the driving forces behind the network evolution Review of 3G Requirements [1]–[4] 3G wireless systems are required to...

Ngày tải lên: 18/06/2014, 10:05

... functions When a source end sends a message requesting the receiving end to perform a specific function, the receiver executes the command and reports the result to the source To illustrate the general ... ACKNOWLEDGE message to the CN, indicating that necessary resources in the target RNC have been prepared On receiving the acknowledgment from the target RNC, the CN sends a RELOCATION COMMAND to the ... the user’s packets corresponding to the requested QoS, reserves necessary resources by setting some parameters in the scheduler (such as the bandwidth on the outgoing interface, the right buffer...

Ngày tải lên: 18/06/2014, 10:05

... dBm Because the receiver noise figure is dB and the receiver is required to provide an interference margin of dB, the noise and interference density of the receiver ϭ ϩ Ϫ 174 ϭ Ϫ166 dBm/Hz The input ... clutter However, because necessary margins have been included in the design, the signal strength everywhere in the cell will be within the prescribed limit Notice that if the requirement on the ... coverage limit The design usually involves determining the number of base stations and their locations that would provide the necessary coverage in a serving area, meet the desired grade of service,...

Ngày tải lên: 18/06/2014, 10:05

... Internet Control Message Protocol IEEE Institute of Electrical and Electronic Engineers IETF Internet Engineering Task Force IMEI International Mobile Station Equipment Identity IMT-2000 International ... Transmission EDGE Enhanced Data Rates for GSM Evolution EIA Electronic Industry Association EIR Equipment Identity Register EIRP Effective (or Equivalent) Isotropic Radiated Power ETSI European Telecommunications ... Mobile Group SMS Short Messaging Service SM-SC Short Messaging Service Center SMS-IWMSC SMS Interworking MSC SMS-GMSC SMS Gateway MSC SNDC Subnetwork-Dependent Convergence SNDCP Subnetwork-Dependent...

Ngày tải lên: 18/06/2014, 10:05