The invention relates to a telecommunication system comprising at least a first station and a second station for providing a telecommunication service via at least one communication channel with a time-frame structure with at least one group of timeslots, in which group at least two timeslots are flexible timeslots each being (re)allocatable to an uplink or a downlink.
The invention also relates to a station for use in a telecommunication system, and to a method for use in a telecommunication system, and to a processor program product to be run via a processor in a station in a telecommunication system.
Such a telecommunication system for example corresponds with a time division duplex (TDD) cellular telephone system or with a Time Division Code Division Multiple Access (TD-CDMA) system, with said first station for example being a base station or a node etc. and with said second station for example being a mobile station etc., without excluding both stations being base stations or nodes or mobile stations etc. A flexible timeslot is either allocated to an uplink or a downlink respectively and can then be re-allocated to a downlink or an uplink respectively, or has not yet been allocated to whatever link and can then be allocated to an uplink or a downlink.
A prior art telecommunication system is known from EP 1 122 895 A1, which discloses in its paragraph 0001 a time division duplex cellular telephone system (a telecommunication system) comprising as shown in its FIG. 1 at least a Base Transceiver Station (for example a first station) and a Mobile Station (for example a second station) for providing as disclosed in its paragraph 0015 a telecommunication service via at least one communication channel with a time-frame structure with a plurality of timeslots (at least one group of timeslots) having reassignable timeslots as disclosed in paragraph 0015 (flexible timeslots which can be allocated to an uplink or a downlink).
The prior art telecommunication system solves the problem of maximizing system capacity while keeping interference to a minimum in a telecommunication system where asymmetrical data rates between uplinks and downlinks may exist. However, for deciding which timeslot is to be assigned to which link, the prior art telecommunication system requires many complex interference detections (calculations), which is not practical. Especially where asymmetrical data rates between uplinks and downlinks may exist, not just base-station-mobile-station-interference needs to be detected, but also base-station-base-station-interference and mobile-station-mobile-station-interference need to be detected.
The known telecommunication system is disadvantageous, inter alia, due to not being practical.
It is an object of the invention, inter alia, of providing a telecommunication system as defined in the preamble which is more practical.
It is a further object of the invention, inter alia, of providing a station as defined in the preamble which is more practical.
It is a yet further object of the invention, inter alia, of providing a method as defined in the preamble which is more practical.
It is also an object of the invention, inter alia, of providing a processor program product as defined in the preamble which is more practical.
The telecommunication system according to the invention comprises at least a first station and a second station for providing a telecommunication service via at least one communication channel with a time-frame structure with at least one group of timeslots, in which group at least two timeslots are flexible timeslots each being (re)allocatable to an uplink or a downlink, wherein in said group at least one timeslot is a fixed uplink timeslot, at least one timeslot is a fixed downlink timeslot, and said at least two flexible timeslots comprise a first number of timeslots having a priority of an uplink kind and a second number of timeslots having a priority of a downlink kind.
By defining in said group at least one timeslot to be a fixed uplink timeslot, which can not be re-allocated to a downlink, and by defining at least one timeslot to be a fixed downlink timeslot, which can not be re-allocated to an uplink, with said at least two flexible timeslots being (re)allocatable timeslots comprising a first number of timeslots having uplink priorities and a second number of timeslots having downlink priorities, a more practical telecommunication system has been created which requires less interference detections (calculations) due to being guided by said uplink and downlink priorities while combining fixed and flexible timeslots.
A first embodiment of the telecommunication system according to the invention is defined by claim 2.
By defining per (sub)frame one fixed uplink timeslot, one fixed downlink timeslot, with all other timeslots in said (sub)frame being (re)allocatable to an uplink or a downlink, a first embodiment has been created which is low complex, due to said first number of (subsequent) timeslots and said second number of (subsequent) timeslots coinciding. Said one kind of priority increasing and said other kind of priority decreasing per timeslot keep interference at a low level due to keeping maximum distance between uplink and downlink timeslots. After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will be required for checking interference constraints, possibly per service.
A second embodiment of the telecommunication system according to the invention is defined by claim 3.
By using rules which take into account at least one adjacent cell for defining per (sub)frame that said first number of (subsequent) timeslots is situated at one side of said group of timeslots and that said second number of (subsequent) timeslots is situated at the other side of said group of timeslots, with both numbers of (subsequent) timeslots partly overlapping or not, thereby possibly further defining priorities, a second embodiment has been created which, compared to said first embodiment, is a little bit more complex, but still of low complexity, and which keeps interference at a minimum while now taking into account neighboring cells. After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will be required for checking interference constraints, possibly per service.
A third embodiment of the telecommunication system according to the invention is defined by claim 4.
By using interference detection results (possibly per service) for defining uplink and downlink priorities, a third embodiment has been created which, compared to said first and second embodiment, is a little bit more complex, but still of low complexity compared to prior art solutions due to just using said interference detection results (possibly per service) for defining increasing/decreasing priorities, thereby for example preventing that some of the timeslots of the group of timeslots join said first number of timeslots or join said second number of timeslots. This third embodiment keeps interference at a minimum while now taking into account interference detection results (possibly per service). After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will no longer be required for checking interference constraints, due to these interference detections being made beforehand possibly per service), which may speed up the (re)allocation procedure.
A fourth embodiment of the telecommunication system according to the invention is defined by claim 5.
Generally said at least one of said stations comprising the memory will correspond with the base station or the node etc. However, a mobile station comprising this memory is not to be excluded, for example for negotiating with said base station or said node etc., or for example for informing said base station or said node etc., or for example for communicating with another mobile station etc.
A fifth embodiment of the telecommunication system according to the invention is defined by claim 6.
Generally said at least one of said stations comprising the allocator will correspond with the base station or the node etc. However, a mobile station comprising this allocator is not to be excluded, for example for informing said base station or said node etc., or for example for communicating with another mobile station etc. Generally said at least one of said stations comprising the interference detector will correspond with the base station or the node etc. for detecting base-station-mobile-station-interference and base-station-base-station-interference. However, a mobile station comprising this interference detector is not to be excluded for detecting mobile-station-mobile-station-interference and possibly base-station-mobile-station-interference, for example for negotiating with said base station or said node etc., or for example for informing said base station or said node etc., or for example for communicating with another mobile station etc.
Said interference detector for example performs the interference measurements disclosed in EP 1 122 895 A1, which discusses in its paragraph 0020 the measuring of relative signal strengths, of distances, of emitted power, of (required) bit rates etc.
A sixth embodiment of the telecommunication system according to the invention is defined by claim 7.
Generally said at least one of said stations comprising this processor will correspond with the base station or the node etc. However, a mobile station comprising this processor is not to be excluded, for example for negotiating with said base station or said node etc., or for example for informing said base station or said node etc., or for example for communicating with another mobile station etc.
The invention is based upon an insight, inter alia, that some timeslots should be fixed and others should be flexible when creating a more practical system, and is based upon a basic idea, inter alia, that uplink and downlink priorities can be defined for supporting said (re)allocating.
The invention solves the problem, inter alia, of providing a more practical telecommunication system, and is further advantageous, inter alia, in that said uplink priorities and downlink priorities keep interference at a minimum due to selected timeslots from said first number of timeslots and selected timeslots from said second number of timeslots being selected (read: getting their priorities) in accordance with getting minimum interference.
It should be noted that the article “Comparisons of Channel Assignment Strategies in Cellular Mobile Telephone Systems” by Ming Zang and Tak-Shing P. Yum in IEEE Transactions on Vehicular Technology Vol. 38 No. 4 dated November 1989 discloses a first channel of a cell having a maximum local-use priority and a last channel of this cell having a maximum borrowing priority in a channel borrowing environment. Due to said borrowing priorities defining an order in which channels are to be borrowed by neighboring cells, the telecommunication system defined in this article is completely different from the telecommunication system according to the invention. Further, said article does not discuss the difference between uplinks and downlinks, and does not mention any uplink priorities and downlink priorities, and does not disclose that some timeslots should be allocated fixedly to an uplink or a downlink and that others should be (re)allocatable to an uplink or a downlink flexibly.
Embodiments of the station according to the invention, of the method according to the invention and of the processor program product according to the invention correspond with the embodiments of the telecommunication system according to the invention.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments(s) described hereinafter.
The telecommunication system shown in
The first station 10 shown in
The second station 30 shown in
First station 10 and second station 30 communicate with each other via communication channel 50, thereby using one or more uplink timeslots and one or more downlink timeslots. In case this communication requires more downlink capacity, for example due to video information needing to be sent down, either an uplink timeslot must be re-allocated to a downlink timeslot, or a timeslot not yet allocated must be allocated to a downlink timeslot. In case a third station enters the cell in which said first station 10 is located and wants to communicate with or via said first station 10, one or more uplink timeslots and one or more downlink timeslots are required. Then these one or more uplink timeslots and one or more downlink timeslots must be allocated, either by allocating one or more timeslots not yet allocated, and/or by re-allocating uplink timeslots and/or downlink timeslots.
Said communication channel 50 has a time-frame structure with at least one group or (sub)frame of timeslots, in which group or (sub)frame at least two timeslots are flexible timeslots each being (re)allocatable to an uplink or a downlink. According to the invention, in said group or (sub)frame at least one timeslot is a fixed uplink timeslot, at least one timeslot is a fixed downlink timeslot, and said at least two flexible timeslots comprise a first number of timeslots having a priority of an uplink kind and a second number of timeslots having a priority of a downlink kind. These flexible priorities are used for selecting the timeslot to be (re)allocated. In case of an extra uplink (downlink) timeslot is required, the timeslot with the priority of an uplink (downlink) kind having the highest value is chosen.
According to a first embodiment of the telecommunication system according to the invention, a first allocation overview as shown in
This first embodiment is low complex, due to said first number of (subsequent) timeslots and said second number of (subsequent) timeslots coinciding. After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will be required for checking interference constraints, possibly per service.
According to a second embodiment of the telecommunication system according to the invention, rules are used for defining locations for said first number and said second number of timeslots, thereby taking into account neighboring cells. Said group of timeslots corresponds with a (sub)frame of a cell, with one timeslot of said first number of timeslots being located at one end of said at least two flexible timeslots and having a maximum priority of an uplink kind and with further timeslots of said first number of timeslots having lower (decreasing when looking from this one end, increasing when looking from the other end) priorities of an uplink kind, and with one timeslot of said second number of timeslots being located at the other end of said at least two flexible timeslots and having a maximum priority of a downlink kind and with further timeslots of said second number of timeslots having lower (decreasing when looking from this other end, increasing when looking from the one end) priorities of a downlink kind.
Suppose timeslot TS0 is a fixed downlink timeslot, timeslot TS1 is a fixed uplink timeslot, and timeslots TS2-TSN are flexible timeslots. Said rules (without excluding other rules) are for example as follows:
By using said rules for defining per (sub)frame that said first number of (subsequent) timeslots TSL to TSN is situated at one side of said group of timeslots and that said second number of (subsequent) timeslots TS2 to TSK is situated at the other side of said group of timeslots, a second embodiment has been created which, compared to said first embodiment, is a little bit more complex, but still of low complexity, and which keeps interference at a minimum while now taking into account neighboring cells. After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will be required for checking interference constraints, possibly per service.
According to a third embodiment of the telecommunication system according to the invention, a second allocation overview as shown in
As a result, as shown in
By using interference detection results (possibly per service) for defining uplink and downlink priorities, a third embodiment has been created which, compared to said first and second embodiment, is a little bit more complex, but still of low complexity compared to prior art solutions due to just using said interference detection results (possibly per service) for defining said increasing and decreasing priorities, thereby for example preventing that some of the timeslots of the group of timeslots join said first number of timeslots or join said second number of timeslots. This third embodiment keeps interference at a minimum while now taking into account interference detection results (possibly per service). After a timeslot has been selected (based upon uplink or downlink priorities) for being (re)allocated to an uplink or a downlink, generally one or more interference detections will no longer be required for checking interference constraints, due to these interference detections being made beforehand (possibly per service), which may speed up the (re)allocation procedure.
The invention is based upon an insight, inter alia, that some timeslots should be fixed and others should be flexible when creating a more practical system, and is based upon a basic idea, inter alia, that uplink and downlink priorities can be defined for supporting said (re)allocating.
The invention solves the problem, inter alia, of providing a more practical telecommunication system, and is advantageous, inter alia, in that said uplink priorities and downlink priorities keep interference at a minimum due to selected timeslots from said first number of timeslots and selected timeslots from said second number of timeslots being selected in accordance with getting minimum interference (by staying away from each other as far as possible and/or as long as possible and/or by using interference detection results).
In station 10 (30) as shown in
The expression “for” in for example “for transmitting” and “for receiving” does not exclude that other functions are performed as well, simultaneously or not. The expressions “X coupled to Y” and “a coupling between X and Y” and “coupling/couples X and Y” etc. do not exclude that an element Z is in between X and Y. The expressions “P comprises Q” and “P comprising Q” etc. do not exclude that an element R is comprises/included as well. The terms “a” and “an” do not exclude the possible presence of one or more pluralities.
Although the first embodiment shown in
Number | Date | Country | Kind |
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02079040.8 | Oct 2002 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB03/04096 | 9/18/2003 | WO | 3/29/2005 |