WO2013033918A1

WO2013033918A1 - A method, an apparatus and a computer program product for flexible tdd configuration

Info

Publication number: WO2013033918A1
Application number: PCT/CN2011/079547
Authority: WO
Inventors: Chunyan Gao; Wei Hong; Erlin Zeng; Jing HAN; Haiming Wang
Original assignee: Renesas Mobile Corporation
Priority date: 2011-09-09
Filing date: 2011-09-09
Publication date: 2013-03-14

Abstract

A method, an apparatus for wireless communication and a computer program product for detecting an interference in a subframe in a first position of a first time division duplex configuration; detecting an uplink subframe in a first position of a second time division duplex configuration; and selecting the second time division duplex configuration.

Description

A METHOD , AN APPARATUS AND A COMPUTER PROGRAM PRODUCT FOR FLEXIBLE TDD CONFIGURATION

FIELD OF THE INVENTION

The invention relates to mobile communication networks. More specifically, the invention relates to the radio interface between an apparatus for wireless communication and a network element, comprising flexible uplink/downlink configuration for time division duplex.

BACKGROUND OF THE INVENTION

Long Term Evolution (LTE) was introduced in release 8 of the 3^rd Generation Partnership Project (3GPP) which is a specification for 3^rd generation mobile communication systems. LTE is a technique for mobile data transmission that aims to increase data transmission rates and decrease delays, among other things. 3GPP release 10 introduced a next version, LTE Advanced, fulfilling 4^th generation system requirements.

Both LTE and LTE Advanced may utilize a technique called time division duplex (TDD) for separating the transmission directions from the user to the base station and back. In TDD mode, the downlink and the uplink are on the same frequency and the separation occurs in the time domain, so that each direction in a connection is assigned to specific timeslots .

Herein, the term "downlink" (DL) is used to refer to the link from the base station to the mobile device or user equipment, and the term "uplink" (UL) is used to refer to the link from the mobile device or user equipment to the base station.

One benefit of the LTE TDD system is an asymmetric uplink-downlink allocation. This is obtained by providing seven different semi-statically configured uplink-downlink configurations. These allocations can provide from 40% to 90% of the DL subframes. The uplink-downlink configurations according to Table 4.2-2 of 3GPP specification TS 36.211 V10.2.0 (2011-06) are illustrated in Figure 1.

The current specification proposal assumes the same TDD configuration in each cell to avoid interference between UL and DL either between two base stations or between two user equipments. However, in a local area (LA) network, due to a small number of active user equipments per cell, the traffic situation may fluctuate frequently. The TDD reconfiguration must adapt to the traffic to improve resource efficiency and provide power saving.

The 3GPP has agreed on a Study Item on LTE

TDD for DL-UL Interference Management and Traffic Adaptation, to further evaluate the gain from traffic adaptation and to study the additional TDD DL-UL interference mitigation method in multi-cell scenarios

In case of flexible TDD configuration in each cell independently without coordination, the DL-UL interference problem will need to be considered. Figure 2 illustrates the interference situation. The interference occurs for example where a femtocell is inside a macrocell and user equipments 100, 101 are located close to each other. Base stations 140, 150 cause interference to each other on the downlink control channel, as well as user equipments 100, 101 on the uplink channel. In the example, the interference occurs between TDD DL-UL configurations 1 and 0, at subframes 4, wherein configuration 1 comprises subframes DSUUD and configuration 0 subframes DSUUU.

The DL-UL interference in flexible subframes may degrade the signal-to-noise ratio significantly. For the data transmission in a flexible subframe, link adaptation and HARQ may help adapting to the interference level. The control signalling to be transmitted in the flexible subframe is more sensitive to the interference due to lack of Hybrid Automatic Repeat Request (HARQ) , and it will further reduce the throughput. The lack of effective solution to this problem leads to inefficient resource utilization, especially in cells with a small number of users, where the traffic situation changes more frequently.

PURPOSE OF THE INVENTION

The purpose of the invention is to propose a new method, an apparatus for wireless communication and a computer program product to avoid interference to or from downlink control channels.

One possible solution to the aforementioned problem is to move the control channels to subframes with less interference. For UL control, i.e, the ACK/NACK feedback, this will require new feedback timing to be specified. For DL control of Physical Downlink Control Channel (PDCCH) , moving it to another subframe would mean that DL transmission and UL transmission had to be scheduled in a subframe earlier than according to the current standard. Moving the subframe in the proposed manner is called pre- scheduling. A further purpose of the invention is to enable the pre-scheduling procedure.

SUMMARY

The invention discloses a method, comprising detecting an interference in a subframe in a first position of a first time division duplex configuration; detecting an uplink subframe in a first position of a second time division duplex configuration; and selecting the second time division duplex configuration .

In one exemplary embodiment the method comprises setting an uplink grant timing according to the second time division duplex configuration. For time division duplex, the HARQ timing such as grant time or feedback time is determined by the time division duplex configuration. This embodiment is suitable for a situation where the subframe in the first position is to be pre-scheduled and the subframe comprises UL grants for scheduling of a second subframe in a second position after the first position The method can be applied to deriving the new timing for uplink grants scheduling the second subframe in the second position.

In one exemplary embodiment the method comprises setting a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration. This embodiment is suitable for a situation where the subframe in the first position is to be pre-scheduled and the DL grant timing shall be determined.

In one exemplary embodiment the method comprises setting a downlink grant timing for the subframe in the first position by scheduling it from the nearest downlink subframe before the first position .

In one exemplary embodiment the method comprises a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position In one exemplary embodiment the method comprises calculating the resource index for the Physical Uplink Control Channel transmitted in the first position subframe and pre-scheduled by the second position subframe by adding: the index of the first Control Channel Element for the pre-scheduling DL grant in the subframe in the second position for the Physical Downlink Shared Channel in the subframe in the first position; the total number of Control Channel Elements in the downlink control region of the subframe in the first position; and an offset. An example of a suitable offset is N_PUCCH(I), signaled to the user equipment by the eNB .

This embodiment is suitable for a situation where the DL subframe is configured to be pre- scheduled in the subframe in the second position, the ACK/NACK feedback timing for Physical Downlink Shared Channel (PDSCH) in the subframe in the first position is unchanged and the ACK/NACK resource can be derived based on the exemplary embodiment if no explicit signaling is available.

The invention discloses also an apparatus for wireless communication, characterized by being configured to: detect an interference in a subframe in a first position of a first time division duplex configuration; detect an uplink subframe in a first position of a second time division duplex configuration; and select the second time division duplex configuration.

In one exemplary embodiment the apparatus is configured to set an uplink grant timing according to the second time division duplex configuration.

In one exemplary embodiment the apparatus is configured to set a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration. In one exemplary embodiment the apparatus is configured to set a downlink grant timing for the subframe in the first position by scheduling it from the nearest downlink subframe before the first position.

In one exemplary embodiment the apparatus is characterized by a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position. In one exemplary embodiment the apparatus is configured to calculate the resource index for Physical Uplink Control Channel transmitted in the first position subframe and pre-scheduled by the second position subframe by adding: the index of the first Control Channel Element for the pre-scheduling DL grant in the subframe in the second position for the Physical Downlink Shared Channel in the subframe in the first position; the total number of Control Channel Elements in the downlink control region of the subframe in the first position; and an offset.

In one exemplary embodiment the apparatus is configured to operate as part of a user equipment. Examples of the user equipment are a mobile phone, a mobile computing device such as PDA, a laptop computer, a USB stick - basically any mobile device with wireless connectivity to a communication network.

In one exemplary embodiment the apparatus is configured to operate as part of a network element. An example of a network element according to the present invention is an evolved Node B (eNB) . The evolved Node B is a base station according to 3GPP LTE . 3GPP, 3rd Generation Partnership Project, develops specifications for third generation mobile phone systems, and also from Release 8 (Rel-8) the next generation specifications often referred to as LTE, Long Term Evolution. The network element may also be a relay node, Donor enhanced Node B (DeNB) or a similar element providing the functionality of a base station.

The invention discloses also a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer, the computer program code comprising: code for detecting an interference in a subframe in a first position of a first time division duplex configuration; code for detecting an uplink subframe in a first position of a second time division duplex configuration; and code for selecting the second time division duplex configuration.

In one exemplary embodiment the computer program product comprises code for setting an uplink grant timing according to the second time division duplex configuration. In one exemplary embodiment the computer program product comprises code for setting a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration. In one exemplary embodiment the computer program product comprises code for a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position. In one exemplary embodiment the computer program product comprises code for calculating the resource index for the Physical Uplink Control Channel transmitted in the first position subframe and pre-scheduled by the second position subframe by adding: the index of the first Control Channel Element for the pre-scheduling DL grant in the subframe in the second position for the Physical Downlink Shared Channel in the subframe in the first position; the total number of Control Channel Elements in the downlink control region of the subframe in the first position; and an offset.

One benefit of the invention is that it does not require coordination between eNBs within the interference area. Another benefit is utilizing currently specified feedback timing configurations and providing a model to select an effective TDD UL/DL configuration. The invention enables the pre- scheduling function with minimum changes to the current specification. Signaling overhead is saved via implicit determination of the subframe in the second position and implicit mapping of the ACK/NACK resource. The solution provides also backward compatibility with legacy user equipments as minimum implementation and standardization efforts are introduced due to reusing most of the current mechanisms .

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:

Fig. 1 is a table illustrating the TDD uplink-downlink configuration,

Fig. 2 is a diagram illustrating an example of interference between different elements, Fig. 3 is a block diagram illustrating the elements according to the invention; and

Fig. 4 illustrates one exemplary embodiment of different feedback timings and pre-scheduling according to one TDD configuration.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Figure 3 is a block diagram illustrating an apparatus for wireless communication 100 according to an embodiment connected to a mobile communication network. The apparatus 100 comprises at least one controller 110, such as a processor, a memory 120 and a communication interface 130. In one embodiment the apparatus is a computer chip. Stored in the memory 120 are computer instructions which are adapted to be executed on the processor 110. The communication interface 130 is adapted to receive and send information to and from the processor 110. The apparatus 100 is commonly referred to as a user equipment UE or it may comprise a part of a user equipment.

The base station 140 comprises at least one controller 141, such as a processor, a memory 142 and a communication interface 143. In one exemplary embodiment the base station 140 comprises a computer chip executing the functionality according to the invention. Stored in the memory 142 are computer instructions which are adapted to be executed on the processor 141. The communication interface 143 is adapted to receive and send information to and from the processor 141. The user equipment 100 is connected to the base station 140, the connection being formed by radio link 151. From the user equipment's 100 perspective the base station 140 offers the functionality required to connect to the wireless network .

The base station 140 is adapted to be part of a cellular radio access network such as E-UTRAN applying WCDMA technology or similar networks suitable for high speed data transmission. Such networks are often also referred to as 4G or LTE . In this example, the cellular radio access network supports carrier aggregation comprising LTE and HSPA. The base station 140 illustrated in Figure 3 symbolizes all relevant network elements required to carry out the functionality of the wireless network. One example of the base station 140 is the evolved Node B, eNB . The downlink direction DL is defined as from the network 140 to the user equipment 100, and the uplink direction UL is defined as from the user equipment 100 to the network 140.

One solution to avoid interference in control signaling is a method similar to Reverse Packet Data Control Channel (R-PDCCH) : sending the Packet Data Control Channel (PDCCH) in the Physical Downlink Control Channel (PDSCH) region and restricting it in limited Physical Resource Blocks (PRB) . However, this solution would require inter-eNB coordination to protect the PDCCH in those PRBs or to avoid interference from the PDCCH to other cells.

Another solution to avoid interference is moving control channels to subframes with less interference. The feedback timing must be specified for the UL control, for example the ACK/NACK feedback. A procedure called pre-scheduling means moving the DL control of the PDCCH to a subframe earlier than in the current specification. As an example, considering the DL transmission in subframe n, the corresponding grant is moved to preceding subframe n-k. One aspect of the invention is to define the new place for the preceding subframe - the value of k.

The following procedure can be used to derive new timing for UL grants scheduling subframe n+p, if the subframe n is configured to be pre-scheduled, and there are UL grants for scheduling of subframe n+p in subframe n: Selecting a TDD configuration where subframe n is set as UL subframe, while link directions of other subframes in the same configuration period are kept unchanged. According to this TDD configuration the UL grant timing is selected for subframe n+p. This solution enables setting the UL grant timing implicitly if the user equipment is configured to be pre-scheduled.

TDD configurations according to the current specification are illustrated in Figure 1. For example, the user equipment UE is configured with TDD configuration 2 (DSUDD) , and subframe 3 is configured to be pre-scheduled due to interference. Subframe 3 comprises a UL grant for subframe 7, then user equipment UE selects TDD configuration 1 (DSUUD) to get the UL grant timing for subframe 7. In other words, subframe 7 is scheduled in subframe 1.

As another example, the DL grant timing for subframe n is determined if one DL subframe n is configured to be pre-scheduled: selecting a TDD configuration where subframe n is set as UL subframe, while link directions of other subframes in the same configuration period are kept unchanged. According to this TDD configuration, the UL grant timing is selected for subframe n and used as the DL grant timing. For example, the user equipment UE is configured with TDD configuration 2 (DSUDD) , and subframe 3 is configured to be pre-scheduled. The user equipment UE selects TDD configuration 1 (DSUUD) to get the UL grant timing for subframe 3, and is able to move the DL grant for subframe 3 to DL subframe 9. The new UL grant may be discovered within the pre-scheduling as in the following example. The user equipment UE is located in a cell with TDD configuration 6 (DSUUUDSUUD) . If subframe 9 is configured to be pre-scheduled to avoid interference to/from the DL control signalling, then the user equipment UE has to determine a new DL grant timing for subframe 9 and a new UL grant timing for subframe 4, which was previously scheduled by subframe 9. To determine the new timing the user equipment UE has to find a TDD configuration where subframe 9 is set as UL, as for example in TDD configuration 0. According to this configuration, UL subframe 4 is scheduled in subframe 0 and UL grants in subframe 9 will be moved to subframe 0. Also according to the UL grant timing of TDD configuration 0, UL subframe 9 is scheduled in subframe 5 and as a result DL grants for subframe 9 will be sent to subframe 5.

According to another solution, if the subframe n is configured to be pre-scheduled, then the DL grant for this subframe is moved to the nearest DL subframe before subframe n. For example, the user equipment UE is configured with TDD configuration 2 (DSUDD) , and subframe 3 is configured to be pre- scheduled, causing the user equipment UE to search DL grant for subframe 3 in subframe 1. Regarding the previous example according to the UL grant timing of TDD configuration 0, UL subframe 9 is scheduled in subframe 5 and as a result DL grants for subframe 9 will be sent to subframe 6.

An optional procedure for the DL grant is moving to DL subframe 1 or 6 which are special subframes and only have 2 OFDM symbols for DL control. This may be suitable for a situation with limited capability to get the DL grant timing. Alternatively, the previous example may be used for causing the user equipment UE to detect the DL grant in subframes enabling a balanced control capacity. Another benefit is the possibility to define the DL grant timing without explicit signalling.

Another problem is encountered in a situation, wherein, for the user equipment UE whose DL grant is moved from subframe n to subframe n-k, the real DL transmission is still in subframe n. The ACK/NACK feedback timing cannot be determined by the DL grant timing, but it may still be determined by the PDSCH transmission time. A new type of the user equipment UE which supports pre-scheduling in subframe n-k has to be fed back in the same subframe m with a legacy UE which is scheduled in subframe n as shown in Figure 4. According to Figure 4, D denotes a downlink subframe, U an uplink subframe, S a special subframe and D' a pre-scheduled downlink subframe. Arrow 41 indicates ACK/NACK feedback timing for the legacy user equipment, arrow 42 indicates ACK/NACK feedback timing for the pre-scheduled user equipment and arrow 43 indicates a downlink grant with pre-scheduling. The following solution enables ACK/NACK resource mapping without colliding with legacy user equipments.

For the DL subframe n which is configured to be pre-scheduled in subframe n-k, the ACK/NACK feedback timing for PDSCH in subframe n is unchanged. Let n_CCE denote the index of the first CCE for the pre-scheduling DL grant in subframe n-k for the PDSCH in subframe n, and let NCCE denote the total number of CCEs in the DL control region of subframe n, then the PUCCH format I resource can be derived as following, where NCCE=0 if there is no DL control region in subframe n for legacy UEs:

111 1 1

Though DL/UL grants of a new user equipment UE in subframe n can be moved to an earlier subframe to avoid interference, the legacy UEs which need to be scheduled in subframe n still have to be scheduled in that subframe. It means, in some case, there can still be some PDCCH region in subframe n, and the interference from that PDCCH for legacy UEs may need to be handled by other methods, e.g, using a short PUCCH/PUSCH format in neighboring cells. In the above example, DL PDSCH in subframe 4 for both legacy UEs and new UEs with pre-scheduling will provide feedback in the same subframe 8 to guarantee the processing time for PDSCH. Then, in case the index for the 1st CCE of a legacy UEs' grant in subframe 4 and the index for the 1st CCE of a new UEs' grant in subframe 1 are same, they will be mapped to the same PUCCH format I resource according to legacy UEs' ACK/ANCK resource mapping rule. To avoid the collision, the invention introduces one offset when deriving the new UEs' PUCCH format I resource. The offset equals to the total number of CCEs in subframe 4.

Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. In an example embodiment, the application logic, software or instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable medium may comprise a computer-readable storage medium that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The exemplary embodiments can store information relating to various processes described herein. This information can be stored in one or more memories, such as a hard disk, optical disk, magneto-optical disk, RAM, and the like. One or more databases can store the information used to implement the exemplary embodiments of the present inventions. The databases can be organized using data structures (e.g., records, tables, arrays, fields, graphs, trees, lists, and the like) included in one or more memories or storage devices listed herein. The processes described with respect to the exemplary embodiments can include appropriate data structures for storing data collected and/or generated by the processes of the devices and subsystems of the exemplary embodiments in one or more databases.

All or a portion of the exemplary embodiments can be conveniently implemented using one or more general purpose processors, microprocessors, digital signal processors, micro-controllers, and the like, programmed according to the teachings of the exemplary embodiments of the present inventions, as will be appreciated by those skilled in the computer and/or software art(s) . Appropriate software can be readily prepared by programmers of ordinary skill based on the teachings of the exemplary embodiments, as will be appreciated by those skilled in the software art. In addition, the exemplary embodiments can be implemented by the preparation of application-specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be appreciated by those skilled in the electrical art(s) . Thus, the exemplary embodiments are not limited to any specific combination of hardware and/or software.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other.

Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims .

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.

Claims

1. A method, c h a r a c t e r i z e d by:

detecting an interference in a subframe in a first position of a first time division duplex configuration;

detecting an uplink subframe in a first position of a second time division duplex configuration; and

selecting the second time division duplex configuration.

2. The method according to claim 1, c h a r a c t e r i z e d by setting an uplink grant timing according to the second time division duplex configuration.

3. The method according to claim 1, c h a r a c t e r i z e d by setting a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration .

4. The method according to claim 1, c h a r a c t e r i z e d by setting a downlink grant timing for the subframe in the first position by scheduling it from the nearest downlink subframe before the first position.

5. The method according to claims 3 or 4, c h a r a c t e r i z e d by a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position.

6. The method according to claim 5, c h a r a c t e r i z e d by calculating the resource index for the Physical Uplink Control Channel transmitted in the first position subframe and pre- scheduled by the second position subframe by adding:

the index of the first Control Channel

Element for the pre-scheduling DL grant in the subframe in the second position for the Physical Downlink Shared Channel in the subframe in the first position;

the total number of Control Channel Elements in the downlink control region of the subframe in the first position; and

an offset.

7. An apparatus for wireless communication, comprising at least one processor and at least one memory comprising program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

detect an interference in a subframe in a first position of a first time division duplex configuration ;

detect an uplink subframe in a first position of a second time division duplex configuration; and select the second time division duplex configuration .

8. The apparatus according to claim 7, c h a r a c t e r i z e d by being configured to set an uplink grant timing according to the second time division duplex configuration.

9. The apparatus according to claim 7, c h a r a c t e r i z e d by being configured to set a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration .

10. The apparatus according to claim 7, c h a r a c t e r i z e d by being configured to set a downlink grant timing for the subframe in the first position by scheduling it from the nearest downlink subframe before the uplink subframe in the first position .

11. The apparatus according to claims 9 or 10, c h a r a c t e r i z e d by a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position.

12. The apparatus according to claim 11, c h a r a c t e r i z e d by being configured to calculate the resource index for Physical Uplink Control Channel transmitted in the first position subframe and pre-scheduled by the second position subframe by adding:

the index of the first Control Channel

Element for the pre-scheduling DL grant in the subframe in the second position for the Physical

Downlink Shared Channel in the subframe in the first position; the total number of Control Channel Elements in the downlink control region of the subframe in the first position; and

an offset.

13. The apparatus according to claim 7, c h a r a c t e r i z e d by being configured to operate as part of a user equipment.

14. The apparatus according to claim 7, c h a r a c t e r i z e d by being configured to operate as part of a network element.

15. A computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer, the computer program code comprising:

code for detecting an interference in a subframe in a first position of a first time division duplex configuration;

code for detecting an uplink subframe in a first position of a second time division duplex configuration; and

code for selecting the second time division duplex configuration.

16. The computer program product according to claim 15, c h a r a c t e r i z e d by comprising code for setting an uplink grant timing according to the second time division duplex configuration.

17. The computer program product according to claim 15, c h a r a c t e r i z e d by comprising code for setting a downlink grant timing for the subframe in the first position according to the uplink grant timing of a first position in the second time division duplex configuration.

18. The computer program product according to claim 15, c h a r a c t e r i z e d by comprising code for setting a downlink grant timing for the subframe in the first position by scheduling it from the nearest downlink subframe before the first position.

19. The computer program product according to claims 17 or 18, c h a r a c t e r i z e d by comprising code for a downlink subframe set to a subframe in the second position before the subframe in the first position and the ACK/NACK feedback timing for Physical Downlink Shared Channel in the first position, scheduled by the downlink subframe in the second position and is the same as in the Physical Downlink Shared Channel in the first position during detecting the interference in the subframe in the first position

20. The computer program product according to claim 19, c h a r a c t e r i z e d by comprising code for calculating the resource index for the Physical Uplink Control Channel transmitted in the first position subframe and pre-scheduled by the second position subframe by adding:

the index of the first Control Channel

an offset.