Showing papers on "GSM frequency bands published in 1999"

Band selection method for dual-band mobile phone and mobile phone using the same method

Abstract: This invention intends to provide a method capable of automatically selecting one system without a large increase of production cost in a dual band mobile phone of this invention having both PHS and GSM functions. First, a common control unit ( 40 ) retrieves whether or not a SIM card ( 19 ) is mounted on a card mounting unit ( 9 ) by a SIM card retrieval circuit ( 41 ). Next, if the mounting thereof is detected and storage data is read properly from the SIM card ( 19 ), the GSM function is indicated on a mode lamp ( 17 ) so that communication is carried out by an operation of the GSM mode. On the other hand, if the mounting of the SIM card ( 19 ) cannot be detected or data cannot be read from the SIM card ( 19 ), the PHS mode is set up by a mode setting circuit ( 43 ) instead of the GSM mode. Then, the PHS mode is indicated on the mode lamp ( 17 ) so that communication is carried out by an operation of the PHS mode. A mode set to be operating is memorized in a mode memory ( 13 ) and if the power is turned ON, the system starts to operate at this memorized mode.

Transmission method/device and reception method/device

Abstract: PROBLEM TO BE SOLVED: To provide compatibility with global mobile communication system by arranging a subcarrier/time slot of an orthogonal frequency division/ multiplex-time division multi-dimensional connection system so that it corresponds to the subcarrier/time slot of a global mobile communication system. SOLUTION: In a frequency slot, 48 auxiliary carriers are used at an interval of 4.166 Hz in 200 kHz based on 200 kHz which is a frequency band width between the channels of a global mobile communication (GSM) system with an orthogonal frequency division/multiples-time division multi-dimensional connection(OFDM/TDMA) system. The whole length of an OFDM/TDMA time slot containing a guard time becomes about 280 μs with such setting, and therefore two OFDM/TDMA time slots are mapped to one GSM time slot. A known pilot symbol as a GSM frequency channel is inserted at every sixth or eighth subcarrier. COPYRIGHT: (C)2000,JPO

Downlink propagation measurements in the GSM 900 and 1800 MHz bands

Abstract: The authors investigate radio propagation in the GSM 900 and 1800 MHz bands in a typical Swedish suburban environment to determine whether or not it is practically feasible to co-site GSM 900 with GSM 1800 systems. They show that propagation in the GSM 1800 band is considerable higher (about 12 dB) than in the old GSM 900. In many cases this difference can be reduced by using dual band sector antennas with 3 dB higher gain at 1800 MHz. However, they also show that in small cells (radius <1000 m) this difference is of little concern and therefore it is possible to co-locate GSM 1800 sites within existing 900 MHz sites as a cost-effective way to increase the system capacity.

Transmission Method and Transmission Apparatus for Transmitting Signals on the Basis of a OFDM/TDMA-System with pilot symbols

Abstract: The present invention relates to a transmission method and transmission apparatus for transmitting signals on the basis of the OFDM / TDMA system. Multiple subcarriers (subcarriers) which are orthogonal to each other are allocated to a variable number of channels, each channel includes a variable number of subcarriers depending on information to be transmitted by the signal. In the GSM system has a constant number of predetermined GSM frequency channels and a predetermined GSM time slot of a certain number of grouped in GSM frames, the number of the sub-carriers to transmit the signals are allocated in correspondence with the bandwidth of the GSM frequency channels . Therefore, a multiple of one OFDM / TDMA timeslot corresponds to one GSM time slot or its multiples. Pilot symbol is allocated to every n (n is an integer greater than 1) sub-carrier in the GSM frequency channel, the signal is transmitted. The invention also relates to a receiver for receiving corresponding signals and how the receiving device. The channel estimation can be performed with reliability by it (channel estimation) and the equalizer (equalization).

Method for communication with hybrid CDMA/GSM mobile stations

Abstract: The interface protocols are arranged in GSM mode interface standards, using a radio interface (1A) and a first layer specifying the code division multiple access transmission and the other layers of the radio interface speifiying the other functions.