Pulse or digital communications – Repeaters – Testing
Patent
1997-01-13
1999-08-10
Chin, Stephen
Pulse or digital communications
Repeaters
Testing
370329, 370330, 370331, 370332, 370431, H04B 1500
Patent
active
059370025
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to the field of radio communications and then particularly, but not exclusively, to a method of channel hopping between different channels of a radio communications system. The invention also relates to the radio communications system in which the method is implemented.
DESCRIPTION OF THE BACKGROUND ART
The term "channel hopping" is used in this document as a collective designation for hops between different information transmission channels, for instance such as hops solely between frequencies, hops solely between time slots, and hops between both frequencies and time slots in a radio communications system.
The person skilled in this art is well aware of the fact that frequency hopping can be used in a radio communications system to improve the performance of the radio system or to guard against unauthorized listening of the radio communication, among other things. Frequency hopping is carried out in a predetermined order in such systems, without paying attention to the instant quality of the connection. Frequency hopping in radio communications systems is thus not adapted.
There can be established between a transmitter and a receiver of a radio communications system a radio connection over which radio communication can take place. The connection is bidirectional by virtue of a downlink which forms the connection in a direction from a base station in the system to a mobile station, and an uplink which forms the connection in the opposite direction, from the mobile station to the base station. The transmission and reception of radio traffic for different connections is effected on channels which can be defined by a certain frequency in an FDMA system or by a combination of a certain frequency and a certain time slot in a system which uses TDMA (Time Division Multiple Access). In a CDMA system, a channel can be defined by a code. Seen generally, the channels that are available in a radio communications system are liable to be disturbed by other radio traffic to different degrees of disturbance, and also by radio signals on the same channels used for other connections, each channel in the system having a certain interference level. Thus, if each connection uses only one channel, the connections will suffer different levels of interference. The levels of interference in certain connections may be so high as to prevent an acceptable connection quality being obtained. These disparities in connection quality can be levelled out by hopping between different channels, wherewith the connections utilize both channels of low and high interference levels. The use of the high interference channels is therewith spread out between the various connections, and when considering the system as a whole more connections can be given an acceptable quality with the aid of interleaving and error correction coding. Each connection can be allocated a plurality of channels, wherein the system controls the connections as communication proceeds, by causing the connections to hop between the channels in accordance with a given hop rule. This rule may be, for instance, a predetermined pseudo-random series, in which case the connections hop seemingly at random between all available channels; see for instance European Patent Application EP 93905701-4. However, the level of interference may become unnecessarily high when this type of channel hopping is used, since the channels are not always allocated to the connections in an optimal fashion when using a pseudo-random series.
A radio communications system will normally include a number of channels that can be used for connections between a given base station and mobile stations. In this case, it is important that the same channels are not used at the same time for two or more connections between the base station and mobile stations. If two transmitters transmit different signals to their respective receivers simultaneously on one and the same channel, it is very likely that at least one receiver will be disturbed by interference from the tr
REFERENCES:
patent: 4355399 (1982-10-01), Timmon
patent: 4479226 (1984-10-01), Prabhu et al.
patent: 4670906 (1987-06-01), Thro
patent: 4677647 (1987-06-01), Aoyagi
patent: 4716573 (1987-12-01), Bergstrom et al.
patent: 4780885 (1988-10-01), Paul et al.
patent: 4872205 (1989-10-01), Smith
patent: 4984247 (1991-01-01), Kaufmann et al.
patent: 4998290 (1991-03-01), Olenick et al.
patent: 5210771 (1993-05-01), Schaeffer et al.
patent: 5311541 (1994-05-01), Sanderford, Jr.
patent: 5335356 (1994-08-01), Andersson et al.
patent: 5488649 (1996-01-01), Schellinger
patent: 5530917 (1996-06-01), Andersson et al.
patent: 5574974 (1996-11-01), Almgren et al.
patent: 5619524 (1997-04-01), Ling et al.
patent: 5666649 (1997-09-01), Dent
Almgren Knut Magnus
Andersson Claes H.ang.kan
Chin Stephen
Roundtree Joseph
Telefonaktiebolaget LM Ericsson
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