Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Patent
1998-02-17
2000-08-29
Urban, Edward F.
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
455522, 370335, H04Q 730
Patent
active
061121045
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method for transmitting a pilot signal used in a cellular radio system including subscriber terminal equipments and at least one base station where the load is formed at least of the connections of the subscriber terminal equipments to the base station which transmits a pilot signal intended for the subscriber terminal equipments, which subscriber terminal equipments are connected to the base station via channels, which base station is included in an active group list of the subscriber terminal equipment.
The present invention is suitable to be used in radio systems employing Code Division Multiple Access use, i.e. the CDMA technique, and especially in so-called WLL systems (WLL=Wireless Local Loop). The code division multiple access use is a multiple use method based on a spread spectrum technique which has recently been applied to cellular radio systems together with previous FDMA (FDMA=Frequency Division Multiple Access) and TDMA (TDMA=Time Division Multiple Access). CDMA has several advantages in comparison with previous method, such as spectrum efficiency and the simplicity of frequency planning.
In the CDMA system, each base station transmits continuously a pilot signal in such a manner that different sectors or beams of the base station have a specified pilot signal because each sector and beam has a specific base station transceiver unit. It is previously known to use a pilot signal for identifying a base station, beam or sector of the base station. A pilot signal is a spread-coded signal without data modulation which signal each base station transmits continuously to its coverage area. The terminal equipment may identify the base station transceiver units by the pilot signal because the phases of the spreading codes in the pilot signal differ from one another. The subscriber terminal equipments carry out measurements of pilot signals continuously and the subscriber terminal equipments form an active group of the base station transceiver units that provide the best connections, the base station transceiver units included in the group being utilized when new connections are established.
WLL systems are radio systems where a mobile telephone system is used to replace an ordinary wired telephone network. In the WLL system, subscriber terminal equipments are fixedly installed at the user's premises in the similar way as ordinary telephones. In other words, terminal equipments in the WLL system have a wireless subscriber connection to the public switched telephone network, i.e. to the PSTN.
All data transmission systems utilizing a radio channel have disturbances on the radio path, such as multipath fadings of a signal which are caused by a signal that has propagated via different ways to be summed in the receiver. As in the WLL system both the transmitter and the receiver are stationary, multipath fading is caused by the movement of objects in the environment. Thus fading is very slow from the point of view of radio engineering. A fading period generally varies from one second to some seconds. Fading depths may be so significant that they have an effect on the quality of the connection if the subscriber terminal equipment is situated in the boundary area of two cells, for instance.
EP 0564 937 discloses a radio system comprising a base station and several subscriber terminal equipments. The base station comprises means for transmitting a pilot signal and means for establishing a connection on the traffic channel between the base station and the subscriber terminal equipment to the subscriber terminal equipment. The subscriber terminal equipment as described in the reference cited comprises means for detecting the pilot signal and means for determining the difference between the pilot signal transmitted by the base station and the pilot signal received by the subscriber terminal equipment. Furthermore, the subscriber terminal equipment comprises means for storing the pilot signal and the traffic channel signal it has received for compensating disturbance in the traffic
REFERENCES:
patent: 5109390 (1992-04-01), Gilhousen et al.
patent: 5548812 (1996-08-01), Padovani et al.
patent: 5754542 (1998-05-01), Ault et al.
patent: 5884187 (1999-03-01), Ziv et al.
patent: 5912884 (1999-06-01), Park et al.
patent: 5966670 (1999-10-01), Keskitalo et al.
Saario Eija
Virtanen Anu
Nokia Telecommunications Oy
Urban Edward F.
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