Method for allocating resources in a radio communications system

p0001description

p0002Process for Ressourcenzute ._-. Ung tion system in a radio Kommumka-

p0003The invention relates to a method for Ressourcenzuteiiung m a radio Kommunikationss / system, in particular mobile funkss - stem, and designed in this way radio Kommumkationssy- system where resources of the radio interface by Kan le GE forms are provided by the network for multiple connections and are provided to subscriber stations ιr Vielfacnzugπ f for grouting and m αer timing and its waveform differ mnernalb a predetermined Frequenzcandes, and wherein m breaks of Datenuoertragungen more Datenuber- be made transfers.

p0004Radio communication systems allow the establishment of communication links between mobile or fixed subscriber stations and a base station αes network by data th are sent in both directions over the radio interface. For an undisturbed two-way connection from a Teilnenmerstation to its base station (Uplmk) and vice versa (Downlmk) werαen Freqaenzduplex-Verfahrer (Frequency Division Duplex FDD) and Zeitαuplexverfahren (Time Division Duplex TDD applied. In order to distinguish multiple simultaneous connections between individual participants towards each other multiple access methods are used . several participants are separated on the same carrier frequency on the radio interface by different time slots, is a Zeitmultiplexverfa ren (Tiiτe Division multiple

p0005Access TDMA) ago. In addition to the time-division multiplex on the radio interface can further process for separating participants be applied as reispielsweise code division multiplexing (Code Division Multiple Access CDMA), in which the signals for the purpose of unambiguous association Emzelsi- ur.α clean separation with different orthogonal code sequences over the entire bandwidth AVAILABLE spread among coding gain who^¬ the.

p0006In future Universal Mocile Telecommunication System UMTS sin .alpha nybride multiplexing method based on frequenzge^¬ teiltem code division multiple access (Wideband-Code Division Multiple Access -CDMA) and zeitgeteiltem code division multiplexing (Time Division-Code Division Multiple Access TD-CDMA) are provided. In the latter method is a combination of multiple access components FDMA, TDMA and CDMA, characterized by the degrees of freedom frequency, time slot and code, in TDD mode is the transmission sowcnl m uplink direction and in the downlink direction in a common Frequenzoand. An expression of the TD-CDMA Ver NRENs is the Time Division- Synchronous Code Division Multiple Access (TD-SCDMA "¹ Method, which can serve as the TD-CDMA method as an example of the use of the invention without limiting the generality of the invention thereby. The TD-SCDMA trial; scneidet compared to the pure TD-CDMA inter alia by using a synchronization hccngenauen αer receive signals in Uplmk, which improves the detection characteristics αer receive signals.

p0007In mobile radio systems for future generations, the proportion of non-real-time Datenubertragungen will greatly increase. Such non-real-time Datenuoertragungen include typical Internet traffic as WWW (World Wide Web), FTP (File Transfer Protocol), e-mail or SMS (Short Message Service). They are based hen on a packet-oriented data transmission, in which likewise makes a distinction on the timeline, but not front grundig in fixed time slots, but in data packets addressed variable length. On the radio interface, the transmission of such data packets and the signaling contained in their application layer can at effective through short, the respective data packet at Large^¬ Fitted resource assignments can be realized because the individual data packets-acres generally longer transmission sys- breaks occur. Longer delays of, for example 400 ms to a few seconds, the availability, for example, by non and the associated delay in the^¬ transmission of data packets are caused, at Xicht-Ecr.t- time data are unkntiscn.

p0008Real-time Datenubertragungen however, such as voice and Videoubertragungen, are usually carried ln^¬ realized gere exclusive allocations of a resource per connection, although the data rate also occur with them Ubertragungspa sen by however much k rzerer time, for example due to the use of a VAD (Voice actvity Detector) for transmitter deactivation m pauses, or fluctuations. The reason for this resource allocation strict distorted, are delay requirements of, for example, less than 40 ms, .- / oak from the usual resource Zuweisungsverfa reindeer can not always be maintained by <ur- zen Ubertragungspausen.

p0009However, an efficient use of precious resources on the radio interface αer wurαe just the "padding" the Ubertragungspausen the real-time connections with data ar.αe- require rer transmissions. This applies in particular for de TD-CDMA system or a similar system thereto.

p0010In a TD-CDMA method is used per carrier frequency along the time axis the same basic structure as the long been introduced in GSM (Global System for Mobile Communications). Due to the large bandwidth but can be up to 8 housed of 16 possible spreading codes per timeslot, each spreading code defining a physical channel. Among resource that the other should be understood Ubεr- tragungskapazitat that for a Verbmαmg needed is unα generally m UMTS by the triple

p0011Frequency, time slot and code is characterized. For Sprachubertragung m UMTS are needed, for example, only egg^¬ NEN physical channel, that a time slot and a spreading code within a frequency band. For a 128 kbit / s data service, however one needs eight physical channels, ie a time slot with eight spreading codes. The Res^¬ source may be divided among several time slots, for example, they may be needed for a 64 kbit / s data service, for the four physical channels on two

p0012Spreading codes be distributed αem one and two spreading codes to another timeslot. The summary of several individual resources to a greater Ubertragungsres- source is referred to as channel pooling. Each time slot itself can be associated with the Uplmk or Downlmk.

p0013Due to the existence of time slots, the statistical properties of the real-time connections to no over time halfway constant interference situation. Therefore, the number of concurrent connections per time slot, each z. B. has a period of 625 microseconds, results from the maximum permissible intersymbol and Vielfachzugriffsmterferenz and leads to a not most of the time optimally loaded system.

p0014Apart from interference (Soft Blockmg), a wireless communication system to be limited by the number of fixed allocated resources. This is true for example for participants who are inte- grated in Circuit Switched (CS) applications. Each connection can be assigned exclusively to the network as many dedicated channels (dedicated channels DCH), such as for the transmission of the peak value of the data rate of real-time services is required. Allocating a fixed resource is optimized when the real-time application, the put to the disposal exploits bandwidth at any time. at c

p0015However, applications in which non-continuous data ge^¬ are sending their data rate can, however, grow very fast up to the maximum required data rate as Sprachuber- transmission, which has an activity of 50 to 60, the Svstemkapazitat is achieved very quickly and it comes to so-called hard Blockmg.

p0016For better utilization of scarce resources, a strategy already has been known that there is a statistical multiplexing data of different compounds on a channel. The during a break a real Verbmdung released resource wirα while another participant allocated and the Eigent egos owner αie resource or an entity belonging to the same channel pool Emzelres- only source αann return once it becomes active again. The data to be transmitted stream of various compounds are thereby split m short data blocks (bursts) of fixed length and encoded and interleaved in time wear uber- a resource corresponding to the order of arrival. According to their data rate connections much transmission capacity obtained varies dynamically allocated. However, this system makes very high demands on carrion zeitlicne behavior and de Zuver_assιgkeιf of Vielfachzugriffscnemas. Can the system a resource not be released immediately because, for example, the resource request does not arrive, or because the allocation message is disturbed, a collision occurs during the data transfer or data of real-time application will be lost.

p0017To keep the collision or the loss of user data at a bearable minimum, therefore, the multiple access scheme with plenty of redundancy and security must be designed. In a TD-CDMA system for example this means that, although at the same time as 16 codes are available per time slot at your disposal, only a maximum of 8 of these codes simultaneously may be awarded. If more codes are assigned, so that was the time when all communications are simultaneously active coincidentally, drove in voice connections m to an unacceptable Interferenzucerhohung. By voice breaks but most of the time are not used all 8 codes. This and simultaneously used by the maximum number of these "worst case" dimensioned for dedicated channels codes as unused resources. This described herein effect the Soft Capacity limitation and its consequences can be observed in other CDMA systems.

p0018The invention is based on the object of specifying a method, transmitted by the m times less than optimal utilization of a TD-CDMA system or a comparable wireless Kcmmum- cation system by Datenuoerfragungen on dedicated channels additional data from other applications with ertraglichem signaling complexity and geπngstmoglichen mutual interference can be and thereby the Ubertra- is optimally utilized gungskapazitat of the radio interface.

p0019The object is achieved by the features specified in claim 1. A device for this purpose is specified in claim 20th

p0020After m an introduction umπssenen radio Ko munika- be tion system m breaks of data transmissions on dedicated channels made other data transmissions in such a way that these m uplink direction such resources are allocated by the network, which do not swell as dedicated channels data are already assigned. These further data transmissions are preferably non-real-time Datenubertragungen, but it can also in principle be real-time Datenubertragungen. For this sends a dedicated channels-use Datenquel_e after _jeder Ubertragungspause within a data transfer a resource request (Request) to an instance of Res^¬ source management (Radio Resource Management) of the network 5 to which the instance mr allots the exclusively reserved resource back.

p0021In another expression shows a αeαizierter channel-use data source after each Ubertragungspause mC within a data transmission resource management of the network, the end of Ubertragungspause and reaches for it on their unverzogert its allocated dedicated channel again. 5 A reduction in the complexity of the signaling is accomplished by by more wishing to transmit data sources from the network not the unused resources of ιna-: tιven, αe- cated channels-use data sources, but αie because of Soft Capacity no limit as dedicated channels ^ he-C used resources are allocated. This already assigned as dedicated channels resources are allocated to these data sources exclusively. This applies to αieser Passover source at the resumption of activity of the data source guarantees no collision with other data sources instead. ES5 can this be lokiert least as many additional resources a .-- as simultaneously inactive, dedicated channels-use data sources are available. The number of additionally benotigten resources is limited only by the maximum number of different codes. For example es0 at an average 60 - strength by weight Activity-use αer dedicated channels data sources likely that only during 60 ** 3 = 21.6% of the time, all of these data sources are active simultaneously. Thus, in a soft capacity limit can simultaneously max. 8 Codes not real-time data while 5 ^ 8 4 ^ of the time over a range of up to an additional 5 unused (of a total of 16 verfugbaren) codes are transmitted.

p0022Advantageously, thereby drove transmission errors in the resources of the access scheme not hard Kollisio^¬ NEN and possibly data loss, but have a maximum as a short-term interference peaks from which the radio Kommunikationss ^τsystem are much easier to handle. This, in turn, the requirements can be significantly reduced to the power load of Zugriffsscnemas.

p0023The result before. inactive dedicated channels-use data sources additionally suddenly assigned resources m a shared resource, such as the so-called Shared Uplmk C annel USCH summarized.

p0024The other wishing to transmit data sources are resources allocated to this USCH, the allocation for USCH preferably via a. Sιgnalιsιerungsκanal, for example, the so-called Uplmk Ccntrol Channel UCCH, by means of a status indicator, emem called Up ± mk State Flag USF occurs.

p0025In a further embodiment, for each Ubertragungsperi- ode an assignment of the USFs on the physical USCH

p0026(PUSCH) resources sent, which are valid period of employment for the next Uoertra-. The necessary addressing the PUSCH Resscurcen be communicated to the additional wishing to transmit data sources through a suitable signaling. Once a data source wishing to transmit in her UCCH USF has received m connection with one or more PUSCH resources, they may wanrend the next Ubertragungsperiooe on exactly this / these jrce PUSCH Ressc 'r. 'Send. Another embodiment provides the number of PU3CH-

p0027Resources for welcne per Ubertragungspeπode USFs in UCCH to^¬ be ordered, in accordance with the interference level set m of the radio cell from the network according to the activities of the data sources the dedicated channels and / or.

p0028The beginning of Ubertragungspausen m dedicated channels-use data transfers in an advantageous embodiment of the dedicated channels-use data sources to the network as in-band signaling is transmitted.

p0029The ends of Ubertragungspausen n dedicated Kan le-use data transfers of the dedicated channels-use data sources however, an advantageous embodiment of the network on a separate signaling channel, such as the Fast Access Uplmk Cnannel FUACH, are signaled.

p0030After another form the beginnings and ends of Ubertragungspausen of data transfers in the dedicated channels prior network of the radio cell are additionally or exclusively based on Inter erenzmessungen m detected. It can be defined as a threshold for radio cells m further refinement em (first) interference level, below which pauses in data transmissions in the dedicated kanaler. signals, which are assigned by the network for other data transmissions.

p0031em (second) can also for the first interference level lower interference level be set as a threshold for radio cells, the network other data transmissions allocates more (P) USCH resources at below which a certain period without any signaling on present the beginning of a Ubertragungspause a data transmission in the dedicated channels.

p0032Another embodiment provides that a priority of the applications the dedicated channels unused in USCH

p0033Resources are allocated and to Ausschopfung these resources the resources of the currently inactive applications will be allocated to the dedicated channels.

p0034In the following the invention by way of Ausfuhrungsbei- game is explained with reference to diagrammatic representations of the near.

p0035Show it:

p0036FIG. 1 em block diagram of Funl -Kommunikaticnssystems, in particular a mobile radio system,

p0037Fig. 2 is a schematic illustration of the radio interface between subscriber stations and base stations of the

p0038Radio communication network,

p0039Fig. 3 is a schematic illustration viewed from erfmdungsgemaß allocated transmission resources in the uplink direction, multiple time slots within a TDMA frame, and

p0040Fig. 4 seen a schematic representation of erfmdungsgemaß allocated resources within a Zeitscnlitzes over several TDMA frames.

p0041The m Fig. 1 illustrated and exemplary designed as a mobile network radio communication system consists of interlinked Mobilvermittlungsemrichtungen MSC / SGSN, the same time the access to fixed networks such as PSTN, ISDN and IP network manufacture. They are at least, each having a device

p0042RNC connected, each access to at least one of Ba^¬ sisstation Node B_, produces and funktechni for allocating^¬ is responsible genetic resources.

p0043Each base station Node B can build up over a radio interface connections V of unα functions to a plurality of subscriber stations UE, some of which are exemplified. By jeαe base station Node B_ a radio cell Z is formed at least that is combined with other radio cells to e_- ner logical group of radio cells within the cellular mobile radio system.

p0044For each frequency, time and spreizcodeselektiven physical channel a plurality of logical channels are defined, which are mapped onto the physical channels. They are characterized by a respective specific parameter group. Payload such as voice, data are for circuit-switched and packet-oriented applications over log_- see Nutzkanale (Traffic Channel TCH) sent. be rungsmformationen signaling via logical signaling channels (control channel CCH transmitted. The signaling channels may for packet-based traffic such Kurznachπchtenαienste (SMS, CBS) are also for a bit and TDMA frame-synchronization of and used.

p0045For time-critical (realtime RT) data transmissions, such as voice, m known manner for unverzogerten transmission exclusively assigned (dedicated) logical Nutzanale I be furnished. In Fig. 1, the subscriber station UE of the radio cell Z RT data sends m uplink direction to the base station Node B. The subscriber station UE. m can be characterized this case as RT-source. Em logical Nutzanal DCH can consist of one or more physical Emzelres- resources and is heavily fluctuate for the maximum values kender data rates designed. In this mgischen user channel

p0046DCH is the transmission of time-critical data is not delayed by a transmission of non-time-critical Inon realtime NRT) data or time-critical data of other data sources (UE UE.).

p0047The beginning and end of pauses within RT-Datenuber- transmissions are signaled by appropriate means "on the RT-source UE to the base station Node B.

p0048For example, the pause beginning be a curch Indand-Si gnalisierung the associated logical N_^tzkanal DCH notified.

p0049For this purpose, m is the data blocks (bursts, m which are divided information to be transmitted according to a pre-treatment to increase the transmission reliability the, source side special Signalisierungsmformationen m the signaling sierungsanteil S (see FIG. 2) entered a data block and the receiving end of the signaling portion again read.

p0050The signaling for the SendPause Can according to another form of the invention as m FIG. 1 symbolically represents shown, by means of user-specific, earmarked

p0051Signaling channel Fast uplink access channel FUACH done.

p0052Additionally or exclusively, a base station Node B, the break beginning and SendPause determine Z also Annand of the measured interference levels m of the radio cell.

p0053The above stated requirements apply analogously ß for a NRT data source UE. F_ür other data transmissions, preferably NRT Datenuber- transfers, but also possibly RT Datenubertragungen data^¬ sources UE, UE, and resources can be used for an advantageous form of the invention that does not already have been assigned to other data sources described on dedicated Nutzkanalen DCH. These resources form erfmdungsgemaß the logical bearer channel Uplmk Shared Channel USCH. The to^¬ instructions to connect to the physical USCH-resources PUSCH carried m one embodiment of the invention via a further signaling channel, the control channel Uplmk UCCH by a Uplmk State Flags USF. Flags bear in a known manner Signalisierungsmformationen within a data block for a distinction between voice and data transmissions. They continue to be used for transmission of control information packet-switched data services.

p0054In UCCH are per Ubertragungsperiode, this corresponds to m usually the Verwurfelungsdauer for realtime Verbmdungen, ie 20 ms, sent assignments between PUSCH resources and USFs, which are valid for the next Ubertragungsperiode. The necessary addressing the PUSCH resources to know the data sources UE UE according to FIG. 1 by suitable means. For example, these are set in the standard fied specific or permanently from the base station Node B "GE broadcasts". Addressing the PUSCH reserves can a further embodiment also the transition m to USCH mo- dus data sources UE, UE. be communicated. Once, for example, the NRT data source UE her USF finds m conjunction with a or more PUSCH resources in UCCH, she knows that she m this / these and only meters should this / Send these PUSCH resource / s during the next Ubertragungsperiode , If you do not include USF, she must not send. The number of PUSCH resources for which per Ubertragungs^¬ period USFs be assigned in UCCH, is determined by the base station Node B. It depends partly on the activities of the data sources on the dedicated channels, which is the base station Node B via the respective home and outband signaling known and, secondly, by the measured from the base station Node B interference level m of the radio cell Z. The neißt when the interference level m of the radio cell Z is too high, the base station must assume Node B. that z. B. several outband signaling a transmitting on a dedicated channel data source were evaluated which do not receive "the end of a Ubertragungspause", this data sources UE has begun again to send and thus less available PUSCH resources at your disposal.

p0055An exemplary frame structure of the radio interface of a TDD Ubertragungsverfahrer.s can be seen from FIG. 2. After a standing at your disposal Gesamtubertragungsbandbreite of z. B. 20 MHz m is divided 4 part frequency bands Bl .. B4 with a bandwidth of 5 MHz. Each radio cell is assigned to some or all of the partial frequency bands B suitable. This is the FDMA component of the hybrid multiple access method TD-CDMA. Within each sub-frequency band B in accordance with a TDMA component will further dividing the time axis m TDMA Ranmen Tr._R3R_ Constant length, for example 10 ms, instead, the m, for example 16 time slots TS1 to TS16 of also the same amount of time, for example, 625 microseconds, are further divided with ascending numbering. Each TDMA frame the numbering repeated. For the duration of data transfer can be allocated periodically in the TDMA frame every 10 ms e and the same time slot number TS1 to TS16 a subscriber station. There is also the possibility for a certain scheme, the time slots TS periodically to exchange his (Timeslot Hoppmg). Each radio cell are several Ze_.t- slots TS allocated. Em part of these time slots TS is used for the downlink path DL from a base station to a subscriber station and em part for Aufwartsstrecke UL. In between lies em switching point SP, the zwec>: s may be more diverse asymmetric allocation of resources administrated Ubertragungsres- variable. With Channel Poolmg a communication link are respectively one or meh^¬ assigned eral individual resources dynamically to realize connections with different data rates or multiple services to operate on a connection in parallel. In^¬ within the time slots TS are data blocks _^Bursts) transmitted that contain a data part D, a signaling component S and a training sequence T for channel estimation in the case of normal bursts for Nutzkanale.

p0056According to the CDMA component in a time slot TS the information of multiple connections are transmitted by each time slot TS is again spread verbmdungsmdividuell with a participant code sequence. The spreading of individual data symbols of data to be transmitted D in which the receiving end known training sequences embedded T causes within the symbol period T - Q data chips D-chips of duration T. be transmitted. The Q data chips thereby form the verbmdungsmdividuellen participant code. The time slot TS (full slot) are 16 Spreizcooes Cl to C16 of charge.

p0057The combination of a partial frequency band B, a time slot TS and a spreading code C defines a Emzelres- source as the smallest unit for the transmission of useful and SignalislerungsInformationen.

p0058In Fig. 3 by way of example is an allocation of Pesourcen on timeslots and codes within a TDMA frame are illustrated. To this end em TDMA frame n + 1 herausgegrif- fen. After the IC. slots timeslot of his, a total of 16 time is the switching point SP between the Abwarts^¬ trackside DL and UL Aufwartsstrecke accepted. Due to the CDMA component each time slot can be occupied by up to 8 from 16 Emzelresourcen (code) simultaneously.

p0059In other to be received only on managing Nutzkanalen on Aufwartsstrecke UL.

p0060The RT-data source UE in FIG. 1 transmits real-time data

p0061Form of language to their base station Node B. To this end, it is exclusively allocated in time slot 11 of the TDMA frame structure of the base station B as new resource of the Code. 4 Transmission occurs on the logical traffic channel DCH. The resource remains of RT data source UE also reserved the opening breaks away. Another data source UE_ receives from the base station Node B, for their transmission also be allotted a Ubertragungsressource on the DCH, in the example in the time slot 13, the codes 1 to 4 and in the time slot 14, the codes 1, 3, 5 and 8. It therefore appears that a NRT data-th transmission in 128 kbit / s data service. The resource for the further data source UE is now on free verfugbaren codes and also engages in Ubertragungspausen the RT-An ending of UE not in the exclusive RT data source UE approved designated code 4 in time slot 11 to. This is also the case when the other data source UE_^ other codes and / or time slots are assigned in the course of NRT transmission of resource management.

p0062The other data source UE_ could of course also be a RT data source and with one or two codes - commented on a time slot - depending Qualltat the compound. Moreover, calls the example of FIG. 1 is a NRT data source UE, a connection with the base station Node Bl on. your who^¬ pursuant to another aspect of the invention PUSCH-Res^¬ assigned resources on the USCH. In the example, you are the "unused" code 13 and 15 assigned to 15 and 16 m time slots, which em 64 kbit / s data service can be realized. This are collisions with eg the RT data^¬ out source UE and the NRT data source UE effectively^¬ closed. This would not reliably the case, would receive the NRT data source UE for example by a process according to the prior art, the codes 1 to 4 on the time slot 11 for the period of the transmission pauses of RT data source UE assigned. In addition, a further NRT data source UE. The codes 13 and 14 are assigned to the time slot. 13

p0063is shown in Fig. 4 schematically the allocation of resources within an exemplary time slot TS13 over several TDMA frames n, n + 1, .... n + 3 to the data sources UE _. UE, UE and UE. shown.

p0064It is shown that the number of available in Uplmk Shared Channel USCH resources directly on the number of active and dedicated channels DCH resources per TDMA frame, or even a group of TDMA frame, z. B. two or four TDMA frames , depends. The maximum allowable number of used resources per time slot TS13 is assumed in the example. 8 It is also the case shows that the dedicated channels DCH-use data sources UE, UE to wait until the appropriate number of Uplmk Shared Channel (USCH-) is no longer used resources. Therefore, never have more than 8 resources simultaneously in use. If the data sources UE, UE, using the dedicated channels DCH, not wait under certain circumstances more than 8 resources allocation period could be used simultaneously while. For example, this could be the case in the transition from TDMA frame n + 2 n on the TDMA frame + 3 unless αie datasource UE_ s already in the TDMA frame + 2 sends, instead of n to the TDMA frame + to wait. 3

p0065The Uplmk Shared Channel USCH thus contains all the resources that are not used as dedicated channels DCH. The number of actual use for the USCH-transmission resources resulting from the Ubertragungspausen a "f the dedicated channels DCH.