Tài liệu Điện thoại di động mạng lưới Radio P2 doc

... cell radii shown. According to Appendix A.1.2, the 2.6 Allocation of Radio Channels 65 B Code Time User 1 User 2 User 3 User 4 Frequency t f Figure 2.36: Code-division multiplexing, CDM are di erent ... of a medium. The following techniques are used in radio systems: • Frequency-division multiplexing (FDM) • Time-division multiplexing (TDM) • Code-division multiplexing (CDM) • Space-divi...

Ngày tải lên: 15/12/2013, 06:15

... Radio TETRA digital Satellite Radio Broadband Radio Cellular Radio Data Packet Radio Trunked Radio Paging Systems Telephony Cordless 1974: Private MPT 1327Mobile Radio D-Netz digital 1998: Iridium Figure ... digital 1992: Data Radio Modacom INMARSAT-C 1988: LEO Satellite Sys. W-ATM 2000:1997:1996: W-LAN 802.11 HIPERLAN/1 2002: UMTS 1991: DECT digital 1991: Trunked Radio anal...

Ngày tải lên: 15/12/2013, 06:15

... above. Because of the restriction of the radio medium (e.g., ra- dio range), both standards must contain functions for the management and maintenance of the radio network that far exceed the normal ... itself. If the radio channel is Idle for a longer period of time, the HCS provider notifies the MAC sublayer accordingly through HC Free Indication. The CAC sublayer thereby indicates that...

Ngày tải lên: 24/12/2013, 13:17

... antennas. Individual dipoles act as omnidirectional beams. However, if groups of dipoles are used, a certain directional pattern is created through the phase di erence at the receiver, which in a distant ... Satellite Radio Network 757 is approximately 150 times faster than an automobile travelling at 170 km/h. Consequently the fading duration is shorter by a factor of 50 than in terrestri...

Ngày tải lên: 21/01/2014, 19:20

... Subsystem Radio Subsystem O (see below) Points of reference: Interface to Transition to Interface Radio Interface other Networks Figure 3.1: Functional architecture of the GSM mobile radio network 3.2 ... propagation of the radio waves in its equalizer. In the GSM frequency band, shadowing may happen to the radio signals of mobile and base stations; this is partly compensated by t...

Ngày tải lên: 15/12/2013, 06:15

... a comparison of the technical parameters for the radio interfaces of the digital public mobile radio systems (GSM, USDC and PDC). 4.2 The US Digital Cellular System (USDC) 305 1 7 10 11 2 3 4 5 8 9 12 13 14 15 16 19 20 21 22 17 18 24 25 26 27 28 29 30 31 32 33 34 35 36 42 40 6 Figure ... (MPT) made the decision in April 1989 to develop a digital mobile radio standard. Compared with exis...

Ngày tải lên: 15/12/2013, 06:15

... Virtual Working Unit Inter Protocols Radio B-ISDN Access Transcoding Functions Radio Connection Figure 5.14: Use of virtual ATM connections with UMTS-specific protocols for the radio interface offer a defined ... to integrate worldwide the di erent mobile communications systems available today, such as mobile telephone and telepoint, trunked radio, data radio, and satellite radio syst...

Ngày tải lên: 15/12/2013, 06:15

... to any mobile station and is used for sending broadcast and dummy messages. 370 6 Trunked Mobile Radio and Packet Data Radio Licence type C Trunked radio networks for local, geographically tightly ... tightly re- stricted areas. Licence type D Countrywide trunked radio network for mobile data radio applications. Trunked radio networks are divided into two categories based on user...

Ngày tải lên: 15/12/2013, 06:15

... eight di erent tone signals per Radio Identity Code (RIC). This means that a tone receiver with a RIC can produce eight di erent alarm signals. • Numeric radio paging in which the receiver has a display ... caller first dials the paging number and then the suffix number of the radio paging area in which the call is to be transmitted. In addition to terminals and accessories for Cityruf,...

Ngày tải lên: 24/12/2013, 13:17

... first ever mobile radio system in which the base station as well as the mobile terminal transmit on the same radio channel. Yet the two transmission directions are not separated by di erent frequencies; ... Cordless Telephone Systems and 868 MHz, which, unlike CT1, does not collide with other standardized mobile radio services in Europe. Two-level GFSK (Gaussian Frequency Shift Keying)...

Ngày tải lên: 24/12/2013, 13:17