Dynamic processing of the uplink frequency domain in the XDD context

Abstract

The invention relates to a method in a base station for dynamically processing an uplink frequency range in a Cross Division Duplex (XDD) context, the method comprising: - receiving information on UL / DL division from another base station having a larger downlink frequency range; - sending answer information on its own UL / DL division; - determining at least an interference frequency range from the UL / DL division information; - receiving additional information from the other base station on downlink content in the interference frequency range; - processing a signal received in the interference frequency range taking into account the downlink content provided by the other base station in the interference frequency range.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to a method in a base station for processing the uplink frequency domain in a cross division duplex (XDD) context.

[0002] The invention also relates to a base station implementing this method. [Background technology]

[0003] 2. Background of the Invention In 3GPP Release 18, discussions related to Cross Division Duplex (XDD) for Time Division Duplex (TDD), and more generally with examples of areas of deployment scenarios including duplex modes and interference management related to the deployment of duplex operation for NR, were started. Thus, XDD with simultaneous operation of UL and DL on the same TDD carrier but on different frequencies is one of the fields to be further investigated for Release 18.

[0004] For example, the major New Radio (NR) bands, such as 3.5 GHz, or all frequencies in the 6 GHz range, are TDD spectrum. This means that the uplink (UL) and downlink (DL) occur in the same band and are separated by defining specific slots for UL or DL, as shown in Figure 1.

[0005] Figure 1 shows a schematic of TDD in 5G. It does not have a fixed predefined frame format, but rather provides a certain flexibility to assign slots within a frame, i.e. slot configuration periods SCP, to specific directions, and also to assign symbols within a frame to specific directions. For this purpose, a cell-specific slot configuration period according to tdd-UL-DL-ConfigurationCommon is defined in the standard, as shown in the first row of Figure 1, with a flexible slot F intervening in the slot configuration period between uplink slot U and downlink slot D. Intermediate slots D / F and F / U are provided for downlink and flexible symbols and flexible and uplink symbols, respectively.

[0006] Thus, the slot configuration period defines a DL-UL transmission periodicity that includes a downlink-only slot D, an uplink-only slot U, and flexible slots F, D / L, and F / U. The second row of Fig. 1 shows a schematic of a user equipment (UE) specific slot configuration according to tdd-UL-DL-ConfigurationDedicated. Here, four slots of the flexible slots F are left unconfigured. As defined in tdd-UL-DL-ConfigurationCommon, two downlink slots D are inserted at the beginning of the flexible slots and one uplink slot U is inserted at the end of the flexible slots. The third row shows the result of combining cell-specific and UE-specific configurations.

[0007] UE specific information to slot configuration is needed to help the network adjust DL / UL patterns based on the UE needs. Because this adjacent DL or UL region is defined, there is a certain delay across UEs for each HARQ feedback. HARQ feedback needs to have a certain minimum time, but can be delayed until the correct direction timeslot occurs. This introduces additional delays to some devices, depending on the overall configuration.

[0008] Depending on the desired traffic, a configuration can be chosen that offers more DL or UL opportunities. However, DL and UL form a contiguous region since UL / DL switching in the UE takes a reasonable amount of time. However, this allows to remove the duplex filter used in FDD to separate UL and DL frequencies.

[0009] The following table shows the latency calculations provided:

[0010] [Table 1]

[0011] This shows that TDD latency is longer than the equivalent FDD latency. Therefore, subframe / slot switching increases overhead and given that many 5G bands are TDD, meaning unpaired frequency bands, this is a common drawback that is overcome when UL and DL exist in parallel.

[0012] Therefore, the biggest drawback when looking at the TDD spectrum is the delay caused by subsequent UL / DL usage changes. Thus, the RTT loop DL allocation / UL transmission / DL acknowledgement takes correspondingly longer, even longer considering that HARQ retransmissions may also be required. As a result, an XDD evolution is intended in Release 18.

[0013] Figure 2 shows XDD in a TDD frequency band with frequency F depending on time T. According to XDD, any base station, here gNB1, transmits in the outer range of its frequency band, and uplink UL is performed in the central inner range, as shown in Figure 2A. If different gNB2 have different DL / UL ratios configured in the MNO, crosslink interference IF will occur between two nodes on both sides of the uplink central inner range, as shown in Figure 2B.

[0014] Thus, as shown in Figure 2, XDD, or full duplex in TDD bands, allows equal calculations in terms of delays and results as FDD, since XDD is full duplex based on frequency band chunks, i.e. frequency division duplex within the band. This certainly leaves the UE with a challenge to achieve flexible filtering or avoid self-interference.

[0015] XDD, specifically shown in Figure 2 as the Subband Full-duplex option (SBFD), divides a single frequency band into one inner UL band and two outer DL bands, while at the same time resulting in the use of specific frequency chunks in different directions.

[0016] Such a solution significantly reduces latency even in TDD bands. However, as recalled above, it also brings new challenges and rules for the allocation of XDD use and interference scenarios. In particular, areas where neighboring base stations may operate in different directions on the same frequency chunk, leading to base station to base station interference. Typically, one base station is transmitting with high power in a direction to its served UE, regardless of whether the other base station is trying to receive the frequency chunk signal from that UE with minimum sensitivity, thus leading to the above-mentioned base station to base station interference. The receiving base station, within range, also experiences the emission of a neighboring base station as interference to the desired UE signal.

[0017] The present invention deals with interference scenarios arising at base stations, especially when different gNBs use the available spectrum differently. Operators have already pointed out the fact that UL / DL sharing between different gNodeBs should be supported differently to allow flexibility, as they may have different traffic needs. Some devices are more DL, e.g., software, film data transmission, while other devices are UL-centric, e.g., video surveillance. Other devices may rather have equal requirements for DL ​​and UL, e.g., real-time gaming. Therefore, in 3GPP Release 18, the Sub-Band Full Duplex option (SBFD) for TDD bands is considered. Operators have expressed a clear intention to split individual UL / DL at each base station, leading to interference scenarios including BS cross-link interference.

[0018] As a result, it should be possible to configure the frequency chunks used for UL and DL differently for neighboring base stations, as well as to have a certain flexibility in modifying said allocations on a longer time basis. However, this leads to areas of interference when supporting different traffic directions at different base stations in different directions.

[0019] Figure 3 shows possible interference scenarios when XDD is deployed, which means that UL and DL data are present simultaneously in the frequency band while the DL and UL regions are not synchronized, i.e., they are not the same size among all neighboring cells. Figure 3 therefore illustrates the new effect of cross-link interference, which appears primarily compared to synchronized unidirectional TDD.

[0020] Typically, one base station will try to receive with minimum sensitivity in a particular frequency region, while another base station several kilometers away transmits with maximum power in the same frequency chunk. In many such conditions, the base station will experience a signal loss condition, which means that the second base station signal will arrive at the other receiving base station with greater power, and therefore an interference situation exists for the receiving base station.

[0021] Therefore, a base station supporting a larger RX area (UL) will face the corresponding interference on the UL side used by neighboring cells as DL, which means that in this area the neighboring cell DL will be received together with the desired UE UL traffic.

[0022] The present invention focuses in particular on crosslink interference between base stations. As shown in FIG. 3 and outlined in the technical background, there are several interference scenarios that occur when XDD or especially SDFB are deployed. However, the above-mentioned base station inter-cell interference scenario BS_CL_IF appears due to base station crosslink interference that occurs when a base station transmits in a frequency domain (DL) that other base stations already use as a reception domain (UL) in addition to self-interference S_IF and UE crosslink interference UE_CL_IF. Also, due to the appearance of downlink / downlink and uplink / uplink UE inter-cell interference UE_IC_IF, shown by the crossed arrows in FIG. 3, the reception of the UL, i.e. the UE reception, is disturbed by the DL transmission of a neighboring base station. This effect is known and can be handled as long as the received wanted base station signal is significantly higher than the unwanted received base station signal of the neighboring cell. However, the present invention is intended for inter-gNB interference mitigation, but is not limited thereto. The present invention also relates to base station and UE interference.

[0023] According to the prior art, such interference can be prevented by performing synchronized SXDD to avoid such interference scenarios. Another solution is to operate with less power in the respective frequency chunks. Although alternative solutions are possible, they have clear efficiency drawbacks since all base stations must apply the same UL / DL split regardless of the individual traffic needs in the cell. Also, the affected frequency chunks are restricted in their use to avoid interference to neighbors. These frequency chunks are then used only in certain directions or with less power to minimize interference.

[0024] In parallel, the UE cross-cell interference is previously known and solved by the UE making neighboring cell measurements, and thus having knowledge of the neighboring SS blocks, especially the PSS and SSS sequences, the UE can subtract the SS block signals from its received sequences. This method is UE-centric and solves the interference only at the UE side, and such a receiver is called an interference cancellation receiver, i.e., upon receiving information about neighboring cells while making neighboring cell measurements, it subtracts them to achieve a better signal-to-noise ratio while receiving their desired signals.

[0025] Therefore, further alternative and advantageous solutions would be desirable in the art. Summary of the Invention [Problem to be solved by the invention]

[0026] Summary of the Invention The present invention aims to mitigate cross-base station interference, it being noted here that network-assisted cross-base station interference has never been addressed before, and therefore methods other than synchronization have not been deployed as relevant solutions. [Means for solving the problem]

[0027] The invention is defined in its broadest sense as a method for dynamically processing an uplink frequency domain in a cross division duplex (XDD) context in a base station, said method comprising the following steps: receiving information regarding UL / DL splitting from another base station having a larger downlink frequency range, - sending answer information regarding its UL / DL split; - determining at least an interference frequency region from UL / DL split information; receiving additional information from other base stations regarding downlink content in an interference frequency region, - Processing signals received in interference frequency regions taking into account downlink content provided by other base stations in the interference frequency region.

[0028] The invention therefore provides signalling between cellular entities relating to signals in the downlink that can be subtracted. Thus, the base station causing crosslink interference provides additional information on the use / content of the frequency chunks causing the interference. In contrast to the interference correction known from the prior art, the base station does not make measurements but only subtracts the content according to the additional information provided by the other base station. The base stations exchange information on the applied UL / DL ratio but also on the cell-specific signals used in the interfering frequency region.

[0029] The additional information about the content of the interference frequency region allows the base station to know the content transmitted by other base stations in the interference frequency region and does not have to take it into account between the received signals. Typically, a mathematical signal cancellation can then be performed. The invention provides additional information about the use / content of the frequency chunks causing the interference, which allows such cancellation. The interfered base station can perform XDD interference suppression. The information exchange allows to eliminate the BS crosslink interference.

[0030] Advantageously, the additional information regarding the content of the interference frequency region enables the base station to know the content transmitted by other base stations in the interference frequency region, and the step of processing the signal received in the interference frequency region includes subtracting such content in the interference frequency region.

[0031] This has the advantage that the base station simply subtracts content in the interfering frequency region, ie content that it knows about or has the means to know about.

[0032] In one embodiment, the content transmitted by the neighboring base station in the interference frequency region includes a repetitive constant signal.

[0033] This is advantageous since it places cell-specific information that does not change, which is preferred for simplifying the removal of interference signals in the interference frequency region. Advantageously, such information is not individually encrypted for privacy and security reasons, but refers to cell-specific information. Thus, the information remains constant over time and only needs to be provided once.

[0034] Advantageously, the additional information comprises a repeated constant signal at least once to enable the base station to subtract it from the received signal in the interference frequency region.

[0035] This content is provided directly here in the Additional Information. The nature of the content may also be specified in the additional information, as long as the base station has already received this content once and is able to retrieve it, or as long as the base station is aware of this content.

[0036] It is therefore especially adapted to signals and information that can be provided once to, or are also known by, neighboring cells, and is accordingly subtracted from the received signal to eliminate BS cross interference, leaving only the UE signal from its own UE transmitting in the UL.

[0037] Advantageously, the repetitive constant signal is common between the two base stations. This may typically be a synchronization signal, some of which is common to all base stations and therefore easy to subtract by the base stations. The SS block is in fact the simplest and most straightforward content that can be introduced into an interference frequency signal.

[0038] Thus, according to one embodiment, the repetition constant signal is selected from the following: - SS block including PSS, SSS, and PBCH, -BCH / Broadcast information, -System information.

[0039] The invention is therefore typically based on exchanging information regarding system information and related updates provided via neighbouring cells as required, thus allowing coordination for the deployment of these in specific interference frequency regions.

[0040] In a further embodiment, the interference frequency region content includes a transient signal. In such an embodiment, it is useful for the base station to receive at least once the temporary signal within the additional information exchanged in accordance with the present invention.

[0041] Typically, the temporary signal is on-demand system information. Therefore, the interference frequency region is preferably used by the base station with the largest downlink frequency region to transmit on-demand system information to the UE.

[0042] Advantageously, the additional information includes respective signalling when on-demand system information is activated or deactivated or MBMS broadcast.

[0043] This makes it possible to provide information about the occurrence of temporal signals or their changes.

[0044] The present invention allows flexibility compared to static approaches and also avoids the use of such overlapping bands with reduced power and therefore efficiency.The base station is informed about cell-specific signals that can be cancelled within signals received in the interference frequency region.

[0045] This method allows to largely eliminate cross-BS interference without causing large signaling flows on the N2 interface, i.e. the interface between base stations as defined within 3GPP between base stations. The information exchange may be performed in special standardized containers for intra-base station interference synchronization and notification. The information exchange may also be performed or enhanced by proprietary signaling, which is also important if the base stations are from the same vendor, i.e. to have enhanced measures for intra-vendor interference avoidance between base stations.

[0046] According to one embodiment, the information regarding the UL / DL split from another base station having a larger downlink frequency range includes an indication that the uplink frequency range deviates and an indication of the side to which it deviates.

[0047] The information exchange is regarding a particular pre-configuration indicating in which direction the area / side in the UL / DL deviates from the pre-configuration.

[0048] Advantageously, in addition to information regarding the UL / DL split, the uplink boundary, which is the UL / DL switching frequency, is provided.

[0049] With this information the base station can adjust at least one boundary to match and locate the interference. Thus, a base station implementing the method of the invention knows which region UL, respectively region DL, is used.

[0050] According to an advantageous embodiment, a common uplink boundary, being the UL / DL switching frequency, is signalled by the network entities of all involved base stations in order to apply the same frequency for UL / DL switching of all base stations operating at said frequency.

[0051] Therefore, since it is beneficial to concentrate the frequencies affected by interference in only one frequency region, the invention further considers the alignment of at least one frequency boundary, where the UL / DL switching takes place. In order to localize the interference in one frequency region, said alignment is advantageously performed by a network entity that provides one switching boundary for all base stations. Thus, all the above mentioned information exchanges can refer to said region. It also facilitates the exchange and update of information in case of changes in the UL / DL allocation of the base stations. Indeed, in this embodiment, only one frequency region is affected directly for all base stations. This is clearly advantageous compared to scenarios where the UL is concentrated in the inner frequency range and experiences new interference situations compared to UL / DL switching approaches with two lateral frequency regions fixed on one side.

[0052] According to another advantageous embodiment, the maximum allowed UL / DL ratio, at which the base station can decide on UL or DL ​​allocation of frequency resources, is signalled by a network entity.

[0053] According to the alignment of the first UL / DL switching boundary, the maximum allowable UL / DL ratio or the frequency bandwidth allowed to be used for either UL or DL ​​is also advantageously signaled by the network entity to the base station. This has the advantage that not only is one of the boundaries aligned, but the base station can evaluate which may be the area most affected by the base station interference. Thus, a first precaution can be taken to avoid the impact of cross-base station interference. It is still valuable even if the boundaries are not synchronized, because it is known what can be assigned and what others can assign in the opposite direction, and therefore what are the important areas / areas.

[0054] Advantageously, the method further comprises the steps of receiving, in the medium access control of the base station, respective information regarding UL / DL synchronous switching frequencies and respective maximum allowed UL / DL ratios which can also be used for UL or DL ​​by other base stations, and performing, for the medium access control, resource allocation which avoids said frequency regions for delay-critical and high QoS sessions.

[0055] This means that the centralized UL / DL switch point and information about the maximum allowed UL / DL ratio or frequency domain for allocation in either direction, and therefore the amount of spectrum that can also be used for UL or DL ​​by other base stations, is known to the base station medium access control, and the medium access control (MAC) performs the resource allocation accordingly.

[0056] This can be done without receiving information from its neighboring cells, since the base station can thus evaluate the most affected frequency region. In that frequency region it can place especially non-critical communications in order to avoid any impact on delay-critical information exchange with the user equipment. This results in the placement of UL of delay-critical communications in other frequency regions than those that can be used for DL ​​by the surrounding base stations. Thus, regardless of the autonomous UL / DL allocation of the neighboring cells, base station cross interference can only occur in said frequency region where either UL or DL ​​is allowed depending on the base station traffic needs. Further adjustments for this region are independent of the interest of knowing which are the frequency ranges affected by base station cross interference and have a value of their own.

[0057] Furthermore, based on this information, base station vendors can add internal measures between base stations to minimize or mitigate interference. In fact, the vendor may not specify what needs to be done, but rather only the areas that are affected, and the present invention is advantageous in such situations.

[0058] At the very least, it is possible to schedule delay-critical or delay-sensitive applications with their respective 5G QoS outside this potential base station cross-interference region, preferably allocating this region to low-delay critical services such as background downloads or best-effort services. This means that the availability of such information is particularly suitable for Medium Access Control (MAC) to take such information into account for scheduling purposes.

[0059] The present invention also relates to a base station adapted to dynamically process an uplink frequency domain in a Cross Division Duplex (XDD) context according to a method as claimed in any one of the preceding claims, said base station comprising: A transmitting / receiving module for exchanging information about the UL / DL split and additional information about the downlink content related to the interference frequency region; A processing module for determining at least an interference frequency region from the UL / DL split information and for processing signals received in the interference frequency region, taking into account downlink content provided by another base station in the interference frequency region.

[0060] To the accomplishment of the foregoing and related ends, the one or more embodiments comprise the features hereinafter fully described and particularly pointed out in the claims.

[0061] BRIEF DESCRIPTION OF THE DRAWINGS The following description and the annexed drawings set forth in detail certain illustrative aspects and indicative of but a few of the various ways in which the principles of the embodiments may be employed. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings, and the disclosed embodiments are intended to include all such aspects and their equivalents. [Brief description of the drawings]

[0062] [Figure 1] 1 illustrates a schematic diagram of the function of time division duplex (TDD) in 5G. [Diagram 2] 2A-2B show schematic diagrams of XDD in a TDD frequency band for two base stations with different DL / UL ratios. [Diagram 3] 3 illustrates a schematic representation of the interference caused in an XDD context where base stations have different DL / UL ratios; [Figure 4] 1 shows a time diagram of the method of the present invention. [Diagram 5] 3 shows an XDD scheme obtained when implementing the method according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] Detailed Description of the Invention Embodiments In order to more fully understand the present invention, the present invention will be described in detail with reference to the accompanying drawings. The detailed description illustrates and describes what are considered to be preferred embodiments of the present invention. It should be understood, of course, that various modifications and changes in form or details can be easily made without departing from the scope of the present invention. It is therefore intended that the present invention not be limited to the exact forms and details shown and described herein, but to less than the entirety of the invention disclosed herein and claimed below. The same elements are designated by the same reference numerals in different drawings. For clarity, only those elements and steps that are useful for understanding the present invention are shown and described in the drawings.

[0064] 4 is a time diagram of the method of the invention. In a first step S1, the base station gNB2 receives a message MS1 from a neighbouring base station, here gNB1, with an indication on the used downlink / uplink split UL / DL_S1. The base station gNB2 then itself transmits in step S2 to at least the transmitting base station gNB1 a message MS2 also indicating the used downlink / uplink split UL / DL_S2.

[0065] This information exchange between the base stations allows knowing the UL / DL split used and where deviations from the pre-configuration occur. Such a pre-configuration is shown in Figure 2, where the uplink UL is centered in the frequency domain between the two frequency chunks dedicated to the downlink DL. This makes clear the interferer and the frequency domain affected by the crosslink interference that is affected by the deviation. The frequency domains / chunks where the downlink of gNB1 interferes with the uplink reception at gNB2 are known by both base stations after this first information exchange phase of the invention.

[0066] The base station gNB1 then has the possibility to transmit information regarding the use of the affected region US_IF. The base station gNB2 thus receives such information in step S3. According to a preferred embodiment of the invention, this information includes the periodicity and timing of the SS blocks and SIBs.

[0067] More generally, the information about the use of the affected area US_IF can be provided once to the neighboring cells or advantageously includes signals and information that are also known by the neighboring cells. It is therefore simple to subtract them from the received signal to eliminate the BS cross interference. Then only the UE signals from own UEs transmitting in the UL remain.

[0068] This means that the signals are forwarded once to neighbouring base stations including the respective used RNTIs and then only the relevant maintenance information is forwarded. One of the a priori known signals is the PSS, meaning the Primary Synchronisation Sequence which is identical for all base stations. For other a priori known signals such as the SSS or domain SIB, only the respective coding / X-RNTIs and maintenance information need to be provided.

[0069] Prior knowledge can be assumed if both base stations belong to the same region and a specific region-specific SIB is provided, thus the content of said SIB is the same and known a priori by all base stations of said region. If the respective used encoding / X-RNTI used for said transmission is also made available to neighboring base stations and information on when and with what periodicity said information is provided / activated is provided / activated, the base station can mathematically eliminate it in its time and frequency grid to avoid BS cross interference from said transmission. In the simplest situation, the base stations are synchronized, i.e. have the same timing, and therefore only the applied timing needs to be provided to the neighboring cells for elimination, otherwise the timing difference needs to be further evaluated.

[0070] Then, in step S4, the base station gNB2 mathematically subtracts from the received context the signal related to the information provided by the base station gNB1 at the appropriate time, thus improving the UL reception of its surrounding user equipment (UE). According to this embodiment, the base station gNB2 removes certain interfering signals.

[0071] According to an advantageous embodiment, the base station gNB1 also transmits information AC_IF on the activation, frequency periodicity and timing of the region SIB, advantageously together with the start / stop information. Thus, in step S5, the base station gNB2 receives this activation information AC_IF. It then allows the base station gNB2 to mathematically subtract, at the appropriate time, the relevant signal from the received context, which further improves the UL reception of that UE. This embodiment allows the base station gNB2 to remove the instantaneous interfering signal in step S6.

[0072] Advantageously, then, for maintenance, the base station gNB1 also provides information CH_IF on content modification or scheduling modification of SIBs in the frequency chunks related to interference. Thus, in step S7, the base station gNB2 receives this maintenance information CH_IF. The base station gNB2 is then able to perform maintenance of interference handling.

[0073] Note that the UL / DL imbalance between cells may change, but here the change is rather on a longer time basis and relevant information is also exchanged to adapt the above-mentioned mechanisms. Also, if all base stations are employed with the same UL / DL ratio, no cross interference occurs.

[0074] Figure 5 shows diagrammatically how the crosslink interference of base stations is concentrated in one frequency region / chunk. According to this preferred embodiment, if feasible, the UL / DL arrangement of the base stations is adjusted so that the difference is only on one side. If several base stations are involved, a specific UL / DL raster may also be used. This is not necessarily the subject of a specification but of the internal processing of the network vendor. The regular exchange of UL / DL usage between base stations also allows the base stations to minimize causing interference by not using this region, or by using this region with less power, or by transmitting common cell-specific information.

[0075] As shown in FIG. 5, base station gNB2, which has a smaller DL band, i.e. a larger reception band, further receives information from its neighbouring base station gNB1, which provides a downlink in an interfering frequency chunk.

[0076] This is particularly adapted for cases of only moderate deviations, i.e. of the order of 5 or 10 or 20 MHz related to the SS block width. The smaller UL is no longer positioned by the base station gNB2 in the center of the entire frequency range. It rather fits into one of the UL / DL cross-synchronization boundaries SB of the neighboring cells, i.e. locates the cross-interference region only on one side. This is what is shown in Figure 5. It should be noted here that the synchronization boundary SB can also be defined and transmitted by the network itself. It is then advantageously received by the medium access control of any involved base station to take this into account.

[0077] In this case, one of the corresponding frequencies at which the switching from UL to DL is performed in order to achieve the alignment of the interference to one frequency region is here a fixed switching frequency SB, which is signaled by one network entity to all base stations. Thus, all interference is assigned to one frequency region, indicated by the dotted region. Thus, one of the boundaries is fixedly signaled by one network entity, and therefore all base stations have this one fixed switching frequency SB.

[0078] In the resulting downlink region, the base station gNB1 typically transmits system information SIBs as shown in Figure 5. This is possible as soon as the UL / DL ratio allows sufficient bandwidth for SS-block provisioning, in the case of smaller UL / DL deviations between cells. The base station gNB1 causing crosslink interference is transmitting SS blocks in this region, in particular including PSS, SSS and PBCH (BCH corset 0), and further other system information, i.e. SIB1 or SIBs on demand, may be provided.

[0079] The base station implementing the method of the invention is informed about cell-specific signals, i.e. SS blocks and system information, BCH provisioning of on-demand SIBs or subset 0 provided in the crosslink interference region. When the information is provided, only the activation or deactivation of on-demand SIBs or other modifications need to be indicated. Signaling the entire signal transmitted in said region all the time is not a good way from a traffic point of view, and knowing the information about SIBs, i.e. their content and X-RNTI, leads to a situation where said information needs to be transferred only once and only provided when new content information has changed. If the content remains unchanged, only the activation and deactivation of on-demand SIBs needs to be signaled by the interfering base station to the neighboring base station. Thus, now gNB2 knows the timing and additional information of gNB1's transmitted SS blocks and can exclude it accordingly in its UL time / frequency grid.

[0080] The invention therefore allows for a fully flexible use by XDD intra-MNO / intra-frequency overlapping frequency chunks by preferably allocating common cell information to these regions, so that the signal can be known to neighboring base stations as including the periodicity and the used X-RNTI, i.e. the common identity. Then, if on-demand BCH information is activated in the region, i.e. the timing, related to the current SS block, it is only necessary to provide information continuously in said region, where the subcarriers are respectively used.

[0081] In the above detailed description, reference is made to the accompanying drawings which show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Accordingly, the above detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims, appropriately interpreted.

Claims

1. 1. A method for dynamically processing an uplink frequency domain in a cross division duplex (XDD) context in a base station, comprising: receiving information regarding UL / DL splitting from another base station having a larger downlink frequency range; - sending information about its UL / DL split as a response; - determining at least an interference frequency region from said UL / DL split information; receiving additional information from said other base station regarding said downlink content in an interference frequency domain; - processing a signal received in the interference frequency region taking into account the downlink content provided by the other base station in the interference frequency region; A method comprising:

2. 2. The method of claim 1, wherein the additional information regarding the content of the interference frequency region enables the base station to know the content transmitted by the other base station in the interference frequency region, and the step of processing the signal received in the interference frequency region includes subtracting such content in the interference frequency region.

3. The method of claim 2 , wherein the content of the interference frequency region comprises a repetitive constant signal.

4. 4. The method of claim 3, wherein the additional information includes the repetitive constant signal at least once to enable the base station to subtract the repetitive constant signal from the received signal in the interference frequency region.

5. The method of claim 3 , wherein the repetitive constant signal is common between two of the base stations.

6. A repetitive constant signal is - SS block including PSS, SSS and PBCH, - BCH / Broadcast information, - System information, -MBMS Broadcast The method of claim 3, wherein the compound is selected from the group consisting of

7. The method of claim 2 , wherein the content of the interference frequency region includes a transient signal.

8. The method of claim 7 , wherein the temporary signal is on-demand system information.

9. The method of claim 8 , wherein the additional information includes respective signaling when the on-demand system information is activated or deactivated.

10. 10. A method according to any one of the preceding claims, wherein the information regarding UL / DL splitting from another base station having a larger downlink frequency range includes an indication that the uplink frequency range deviates and an indication of the side from which it deviates.

11. The method of claim 10, wherein in addition to the information on UL / DL split, an uplink boundary is provided which is a UL / DL switching frequency.

12. 10. The method according to any one of the preceding claims, wherein a common frequency, one of the UL / DL switching frequencies, is signalled by a network entity for all involved base stations in order to apply the same frequency for UL / DL switching of all base stations operating at that frequency.

13. 10. The method according to any one of the preceding claims, wherein a maximum allowed UL / DL ratio at which the base station can decide on UL or DL ​​allocation of frequency resources is signalled by a network entity.

14. 14. The method according to claim 12 or 13, further comprising: receiving, in a medium access control of the base station, respective information on UL / DL synchronous switching frequencies and respective maximum allowed UL / DL ratios that can also be used for UL or DL ​​by other base stations; and performing, for the medium access control, resource allocation that avoids the frequency regions for delay-critical and high QoS sessions.

15. A base station adapted for dynamically processing an uplink frequency domain in a Cross Division Duplex (XDD) context according to a method according to any one of the preceding claims, comprising: - a transmission / reception module for exchanging information on the UL / DL split and additional information on downlink content related to the interference frequency region; a processing module for determining at least an interference frequency region from said UL / DL split information and for processing signals received in said interference frequency region taking into account the downlink content provided by another base station in said interference frequency region; A base station comprising:

Images