CN107295685B

CN107295685B - Method and apparatus for transmitting short enhanced physical downlink control channel

Info

Publication number: CN107295685B
Application number: CN201610205701.8A
Authority: CN
Inventors: 骆喆; 武卓; 王钧; 沈钢
Original assignee: Nokia Shanghai Bell Co Ltd
Current assignee: Nokia Shanghai Bell Co Ltd
Priority date: 2016-04-01
Filing date: 2016-04-01
Publication date: 2020-11-10
Anticipated expiration: 2036-04-01
Also published as: CN107295685A

Abstract

Embodiments of the present disclosure disclose a method and apparatus for transmitting a short enhanced physical downlink control channel, epdcch. The method comprises arranging physical resource sets of the epdcch in a same set of PRB-pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length; setting the TTI length represented by each physical resource set to be equal to the TTI length of a corresponding Physical Downlink Shared Channel (PDSCH) and a corresponding Physical Uplink Shared Channel (PUSCH), wherein each physical resource set is used for scheduling the corresponding PDSCH; and transmitting downlink control information, DCI, with at least one set of physical resources of the epdcch.

Description

Method and apparatus for transmitting short enhanced physical downlink control channel

Technical Field

Embodiments of the present disclosure relate to the field of communications, and more particularly, to methods and apparatus for transmitting short enhanced physical downlink control channels.

Background

In the recent 3GPP discussion, reducing latency has been introduced on the 3GPP TSG RAN #67 conference. Packet data delay is not only important for the system-perceived responsiveness, but on the other hand it also serves as a parameter that indirectly affects the quality of workload, buffering requirements, stable transmission, and application experience. Currently, in order to reduce packet data delay, the concept of TTI (transmission time interval) shortening has been introduced and discussed since the 3GPP TSG RAN WG1#83 conference.

Conventional physical downlink control channel PDCCH and enhanced physical downlink control channel EPDCCH support only equal TTI lengths (i.e., conventional 1ms TTI), and thus, control signaling of the downlink DL for the shortened TTI should be improved.

In the following, the DL control signaling existing in the prior art is explained in connection with fig. 1and 2. Wherein fig. 1 shows a schematic diagram of a PDCCH in the prior art, and fig. 2 shows a schematic diagram of an EPDCCH in the prior art.

As shown in fig. 1, the PDCCH occupies some orthogonal frequency division multiplexing symbols OS at the beginning of each subframe (regular TTI). Each connected UE decodes downlink control information DCI in a common search space and a terminal-specific search space in the PDCCH. The principle of PDCCH design is to concentrate DCI in a small number of OSs at the beginning of each subframe and distribute them over the entire system bandwidth. Since there are multiple different short TTIs in a subframe, occupying PDCCH-like control signaling of the OS at the beginning of each short TTI would result in a large amount of signaling overhead. Therefore, it is not suitable for shortening of TTI.

The set of physical resources of EPDCCH as shown in fig. 2 occupies some PRBs in each subframe. Each UE is configured to receive an EPDCCH to decode DCI in a terminal-specific search space of a set of physical resources of the EPDCCH. The principle of EPDCCH design is to distribute the DCIs over the entire subframe and concentrate them in some PRBs. The EPDCCH-like control signaling for short TTIs occupies only a small number of PRBs, meaning less signaling overhead, and thus, EPDCCH is suitable for shortening of the TTI.

Since multiple different TTI lengths co-exist in the same subframe, conventional DL control signaling (PDCCH and EPDCCH) cannot meet the requirements in this case. So far, no new DL control signaling for coexistence of multiple TTI lengths has emerged.

Disclosure of Invention

In view of the above problems in the prior art, embodiments of the present disclosure are directed to providing a method and apparatus for transmitting a short enhanced physical downlink control channel, epdcch, that enables a UE to support multiple different TTI lengths in a subframe.

A first aspect of the present disclosure provides a method for transmitting a short enhanced physical downlink control channel, epdcch, comprising: arranging physical resource sets of the sEPDCCH in the same group of Physical Resource Block (PRB) pairs in a time domain, wherein each physical resource set represents the length of a respective Transmission Time Interval (TTI); setting the TTI length represented by each physical resource set to be equal to the TTI length of a corresponding Physical Downlink Shared Channel (PDSCH) and a corresponding Physical Uplink Shared Channel (PUSCH), wherein each physical resource set is used for scheduling the corresponding PDSCH and PUSCH; and transmitting downlink control information, DCI, with at least one set of physical resources of the epdcch.

According to an exemplary embodiment of the present disclosure, wherein setting the TTI length represented by each set of physical resources equal to the TTI length of the corresponding physical downlink shared channel PDSCH and the corresponding physical uplink shared channel PUSCH comprises: the start OS and the end OS of each set of physical resources are set to align with the start OS and the end OS of the corresponding PDSCH and the corresponding PUSCH, respectively.

According to an exemplary embodiment of the disclosure, the method further comprises predefining a search space carrying DCI in the set of physical resources of the epdcch.

According to an exemplary embodiment of the present disclosure, predefining a search space carrying DCI in the set of physical resources of the epdcch comprises: and limiting the number of candidate positions for carrying the DCI in the physical resource set of the sEPDCCH.

According to an exemplary embodiment of the present disclosure, wherein defining the number of candidate positions for carrying the DCI in the physical resource set of the epdcch comprises: defining a number of candidate locations for each set of physical resources to carry the DCI.

According to an exemplary embodiment of the present disclosure, wherein defining the number of candidate positions for carrying the DCI in the physical resource set of the epdcch comprises: and reserving the number of candidate positions for bearing the DCI for the combination of physical resource sets with different TTI lengths.

According to an exemplary embodiment of the present disclosure, predefining a search space carrying DCI in the set of physical resources of the epdcch comprises: defining a priority of candidate locations carrying the DCI in the set of physical resources.

According to an exemplary embodiment of the present disclosure, predefining a search space carrying DCI in the set of physical resources of the epdcch comprises: only the set of physical resources with the requested TTI length is triggered.

According to an exemplary embodiment of the present disclosure, predefining a search space carrying DCI in the set of physical resources of the epdcch comprises: a starting OS is defined for the set of physical resources.

According to an example embodiment of the disclosure, the method further comprises performing UE-specific configuration of the set of physical resources of the epdcch using radio resource control, RRC, signaling.

According to an exemplary embodiment of the present disclosure, wherein the UE-specific configuration includes: an ID of the set of physical resources, a mode of the assigned PRB pair, a starting OS, information of a reference signal for demodulation, a configuration of a PUCCH, and channel state information CSI of zero power.

A second aspect of the present disclosure provides a method for transmitting a short enhanced physical downlink control channel, epdcch, comprising: receiving downlink control information, DCI, transmitted with at least one set of physical resources of the sEPDCCH; blind decoding the DCI to obtain the TTI lengths of the PDSCH and the PUSCH corresponding to the physical resource set; wherein the physical resource sets of the epdcch are arranged in the same set of PRB-pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length; and the TTI length represented by each set of physical resources used for scheduling the corresponding PDSCH and PUSCH is set to be equal to the TTI length of the corresponding physical downlink shared channel PDSCH and the corresponding physical uplink shared channel PUSCH.

According to an exemplary embodiment of the present disclosure, blind decoding the DCI comprises: blind decoding in a predefined search space carrying DCI in the set of physical resources of the sEPDCCH.

According to an exemplary embodiment of the present disclosure, blind decoding the DCI comprises: blind decoding is performed according to the UE-specific configuration of the received physical resource set of EPDCCH.

A third aspect of the present disclosure provides an apparatus for transmitting a short enhanced physical downlink control channel, epdcch, comprising: a first configuration unit configured to arrange physical resource sets of the epdcch in a same set of physical resource block, PRB, pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length; a second configuration unit configured to set a TTI length represented by each set of physical resources to be equal to a TTI length of a corresponding physical downlink shared channel PDSCH and a corresponding physical uplink shared channel PUSCH, wherein each set of physical resources is used for scheduling the corresponding PDSCH and PUSCH; and a transmitting unit configured to transmit downlink control information, DCI, using at least one set of physical resources of the epdcch.

According to an exemplary embodiment of the present disclosure, wherein the second configuration unit is further configured to: the start OS and the end OS of each set of physical resources are set to align with the start OS and the end OS of the corresponding PDSCH and the corresponding PUSCH, respectively.

According to an exemplary embodiment of the disclosure, the apparatus further includes a predefining unit configured to predefine a search space carrying DCI in the set of physical resources of the epdcch.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: and limiting the number of candidate positions for carrying the DCI in the physical resource set of the sEPDCCH.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: defining a number of candidate locations for each set of physical resources to carry the DCI.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: and reserving the number of candidate positions for bearing the DCI for the combination of physical resource sets with different TTI lengths.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: defining a priority of candidate locations carrying the DCI in the set of physical resources.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: only the set of physical resources with the requested TTI length is triggered.

According to an exemplary embodiment of the disclosure, wherein the predefined unit is further configured to: a starting OS is defined for the set of physical resources.

According to an example embodiment of the disclosure, the apparatus further comprises an execution unit configured to perform UE-specific configuration of the set of physical resources of the epdcch using radio resource control, RRC, signaling.

A fourth aspect of the present disclosure is to provide an apparatus for transmitting a short enhanced physical downlink control channel, epdcch, comprising: a receiving unit configured to receive downlink control information, DCI, transmitted using at least one set of physical resources of the sEPDCCH; and a decoding unit configured to blind decode the DCI to obtain a PDSCH corresponding to the set of physical resources and a TTI length of a corresponding physical uplink shared channel, PUSCH; wherein the physical resource sets of the epdcch are arranged in the same set of PRB-pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length; and the TTI length represented by each set of physical resources used for scheduling the corresponding PDSCH and PUSCH is set to be equal to the TTI length of the corresponding physical downlink shared channel PDSCH and the corresponding physical uplink shared channel PUSCH.

According to an exemplary embodiment of the present disclosure, wherein the decoding unit is further configured to: blind decoding in a predefined search space carrying DCI in the set of physical resources of the sEPDCCH.

According to an exemplary embodiment of the present disclosure, wherein the decoding unit is further configured to: blind decoding is performed according to the UE-specific configuration of the received physical resource set of EPDCCH.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure.

Fig. 1 shows a schematic diagram of a PDCCH in the related art.

Fig. 2 shows a schematic diagram of an EPDCCH in the prior art.

Fig. 3 shows a schematic diagram of a method for transmitting epdcch according to an embodiment of the present disclosure.

Fig. 4 shows a schematic diagram of physical resource sets of epdcch of different TTI lengths corresponding to PDSCH of different TTI lengths according to an embodiment of the present disclosure.

Fig. 5 shows a schematic diagram of a method for transmitting an epdcch according to yet another embodiment of the present disclosure.

Fig. 6 shows a schematic diagram of a state where physical resource sets of EPDCCH overlap according to an embodiment of the present disclosure.

Fig. 7 shows a block diagram of an apparatus for transmitting epdcch according to an embodiment of the present disclosure.

Fig. 8 shows a block diagram of an apparatus for transmitting epdcch according to yet another embodiment of the present disclosure.

Detailed Description

The principles of the present disclosure will be described below with reference to a number of example embodiments shown in the drawings. It should be understood that these embodiments are described only to enable those skilled in the art to better understand and implement the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

Fig. 3 shows a schematic diagram of a method 300 for transmitting epdcch according to an embodiment of the present disclosure.

As shown in fig. 3, in step S310, physical resource sets of the epdcch are arranged in the same set of PRB-pairs in the time domain, where each physical resource set represents a respective transmission time interval, TTI, length. In step S320, the TTI length represented by each set of physical resources for scheduling the corresponding PDSCH and PUSCH is set to be equal to the TTI length of the corresponding PDSCH and the corresponding PUSCH. In step S330, downlink control information, DCI, is transmitted using at least one set of physical resources of the epdcch.

Note that in the embodiments of the present disclosure, the TTI refers to a regular TTI (14 OFDM symbols) and a short TTI (2/3/4/7OFDM symbols).

Fig. 4 shows a schematic diagram of physical resource sets of epdcch of different TTI lengths corresponding to PDSCH of different TTI lengths according to an embodiment of the present disclosure. Here, the physical resource set of each epdcch represents its respective TTI length, and the starting and ending OS of the physical resource set of each epdcch respectively coincide with the starting and ending OS in the PDSCH/PUSCH scheduled correspondingly thereto. In the example shown in fig. 4, a plurality of physical resource sets including one physical resource set of regular (14OS) EPDCCH, 3 physical resource sets of 7OS EPDCCH and two physical resource sets of 3/4OS EPDCCH are arranged in a PRB pair of the same time domain. As can be seen from fig. 4, the TTI length of the physical resource set of each epdcch completely coincides with the TTI length of the PDSCH scheduled correspondingly thereto.

Fig. 5 shows a schematic diagram of a method 500 for transmitting epdcch according to yet another embodiment of the present disclosure.

As shown in fig. 5, downlink control information, DCI, transmitted using at least one set of physical resources of the epdcch is received at step S510. In step S520, the DCI is blind decoded to obtain the TTI length of the PDSCH/PUSCH corresponding to the set of physical resources.

Since the mapping to REs is different for the physical resource sets of epdcch of different TTI lengths, the UE can blindly decode DCI of the physical resource sets of multiple epdcch and obtain the corresponding TTI lengths of PDSCH/PUSCH. Even if the(s) EPDCCH physical resource sets overlap. It is noted that the UE will blindly decode the DCI in the set of physical resources of the epdcch of the corresponding TTI length after the OS of the short TTI is received. The actual location of the DCI is set by the eNB.

Fig. 6 shows a schematic diagram of a state where physical resource sets of EPDCCH overlap according to an embodiment of the present disclosure. As shown in fig. 6, in some PRBs, the physical resource set of EPDCCH and the PRBs of two 7OS EPDCCH are overlapping. The UE can decode DCI for a regular TTI in the physical resource set of EPDCCH after receiving the OS in the entire subframe. Also, the UE can decode DCI for a TTI of 7OS in the physical resource set of epdcch after receiving the OS of one slot.

For the regular TTI, the UE is required to monitor only 1 or 2 EPDCCH physical resource sets in the subframe. However, monitoring the set of physical resources of the plurality of epdcch in the subframe will increase the complexity of blind decoding for the UE. According to an embodiment of the present disclosure, the method 300 may further include predefining a search space carrying DCI in the set of physical resources of the epdcch. The manner in which the search space is predefined to reduce the complexity of blind decoding is discussed further below.

According to one embodiment of the present disclosure, only some candidate positions are available for carrying DCI in the physical resource set of epdcch. The UE only needs to blindly decode each candidate position therein. Thus, the limited number of candidate positions carrying DCI can reduce the complexity of blind decoding. When blindly decoding a candidate with multiple TTI lengths, the UE will start the test with the shortest TTI length.

In particular, a small number of DCI candidates may be predefined for each physical resource set of epdcch. The number of DCI-bearing candidate positions in the set of physical resources of the sPDCCH depends on the TTI length. The total number of candidate positions in a subframe should be approximate for each TTI length. On the other hand, DCI-bearing candidate positions may also be predefined for combinations of physical resource sets of some epdcch of different TTI lengths. The total number of candidate positions in the subframe carrying the DCI should be approximate for each combination.

According to one embodiment of the present disclosure, the priority of candidate locations may be defined in the search space of a combined or set of physical resources of the epdcch. The UE will first test candidate locations with high priority. If DCI is found in a candidate location with a priority, the UE will not test candidate locations with other priorities, e.g., in one subframe. In this way, the UE need not blindly decode all candidate locations. For example, the candidate position of the shortest TTI length is given higher priority. This is particularly useful where the TTI length does not change in one subframe (TTI length may change from one subframe to another).

Not all physical resource sets of epdcch of different TTI lengths need to be monitored. The UE only tries to blind decode DCI in the set of physical resources of the epdcch of the requested TTI length. Thus, according to one embodiment of the disclosure, only the set of physical resources having the requested TTI length may be triggered, such that the one or more requested TTI lengths are transmitted by the eNB to the UE. For example, the UE can monitor only a single TTI length, and the serving base station can switch the TTI length operated by RRC signaling. An example of trigger signaling can be shown, for example, by the following list:

MonitorTTILength-r14::＝SEQUENCE(SIZE(1..4))OF ENUMERATED{OS2,OS3/4,OS7,SF}

according to one embodiment of the present disclosure, a starting OS may also be defined for a set of physical resources of the epdcch. That is, after the start OS is defined, the UE may perform blind decoding starting from the defined start OS, instead of starting the blind decoding with each OS as the start OS. This also reduces the complexity of blind decoding. For example, the starting OS of the set of physical resources for the epdcch for 7OS is OS # startSymbol-r11and OS # 7. And the starting OS of the physical resource set for the epdcch of 3/4OS is OS # startSymbol-r11, OS #3, OS #7, and OS # 10.

According to an embodiment of the disclosure, the method 300 further comprises performing UE-specific configuration of the set of physical resources of the epdcch using radio resource control, RRC, signaling. When the UE receives the configuration, the DCI in the configured and triggered physical resource set (i.e., search space) of the epdcch is blind decoded. Wherein the UE-specific configuration comprises an ID (meaning TTI length) of a physical resource set of the epdcch, a pattern of assigned PRB pairs, a starting OS, information of reference signals for demodulation, a PUCCH configuration, and a channel state information, CSI, configuration of zero power.

It is noted that, as mentioned above, the starting OS of the set of physical resources of the epdcch has been defined on the premise that the search space has been pre-defined as mentioned above, and thus the starting OS will not be configured anymore. As also mentioned above, candidate locations (related to UE IDs) have been defined for the UE and are therefore also no longer configured.

According to one embodiment of the present disclosure, when configuring a physical resource set of an epdcch, the physical resource set of each epdcch may be configured individually. In this case, the same assigned PRB pair pattern, information of reference signals for demodulation, and channel state information CSI configuration of zero power are allowed to be configured in different physical resource sets of epdcch. The columns in table 1 show examples of configurations of physical resource sets for 7OS TTIs and 3/4OS TTIs:

list 1

According to one embodiment of the present disclosure, when configuring a physical resource set of epdcch, the physical resource sets of epdcch of different TTI lengths may be configured as a combination. In this case, the physical resource sets of the plurality of epdcchs in combination share the pattern of assigned PRB pairs, information of reference signals for demodulation and channel state information, CSI, configuration of zero power. The list in table 2 shows an example of the configuration of the above combination:

list 2

Fig. 7 shows a block diagram of an apparatus 700 for transmitting epdcch according to an embodiment of the present disclosure.

As shown in fig. 7, the apparatus 700 comprises a first configuration unit 710 configured to arrange physical resource sets of an epdcch in the same set of PRB-pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length; a second configuration unit 720 configured to set a TTI length represented by each set of physical resources for scheduling a corresponding PDSCH and PUSCH to be equal to a TTI length of a corresponding PDSCH and a corresponding PUSCH; and a transmitting unit 730 configured to transmit downlink control information, DCI, with at least one set of physical resources of the epdcch.

According to an embodiment of the present disclosure, in the apparatus 700, the second configuration unit 720 is further configured to set the start OS and the end OS of each set of physical resources to be aligned with the start OS and the end OS of the corresponding PDSCH and the corresponding PUSCH, respectively.

Although not shown in the figures, according to an embodiment of the present disclosure, the apparatus 700 further includes a predefined unit that predefines a search space carrying DCI in the set of physical resources of the epdcch.

Although not shown in the figures, according to an embodiment of the present disclosure, the apparatus 700 further comprises an execution unit configured to execute a UE-specific configuration of the set of physical resources of the epdcch using radio resource control, RRC, signaling.

As shown in fig. 8, the apparatus 800 comprises a receiving unit 810 configured to receive downlink control information, DCI, transmitted with at least one set of physical resources of an epdcch; and a decoding unit 820 configured to blind decode the DCI to obtain a PDSCH corresponding to the set of physical resources and a TTI length of a corresponding physical uplink shared channel, PUSCH.

In the apparatus 800, according to an embodiment of the present disclosure, the decoding unit 820 is further configured to blind decode in a predefined search space carrying DCI in a set of physical resources of the epdcch.

In the apparatus 800, the decoding unit 820 is further configured to perform blind decoding according to a UE-specific configuration of the received physical resource set of EPDCCH, according to an embodiment of the present disclosure.

Advantages of the method and apparatus for transmitting epdcch according to embodiments of the present disclosure are at least as follows. First, the eNB no longer needs to explicitly inform the UE of the TTI length of PDSCH/PUSCH. Second, carrier aggregation of carrier elements CC in different TTI lengths is supported as well as asymmetric UL/DL lengths. The primary CC can schedule PDSCH/PUSCH of arbitrary TTI length in the secondary CC. The TTI length of DCI for UL can be different from the TTI length of DCI in PDSCH. Further, the eNB can dynamically switch the TTI length of the UE without signaling the TTI length switch and reconfiguring the new TTI length to the UE. Finally, the set of physical resources of multiple epdcchs of different TTI lengths can share the same reference signal for demodulation, which reduces the overhead of transmission.

The above description is intended only as an alternative embodiment of the present disclosure and is not intended to limit the present disclosure, which may be modified and varied by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for transmitting a short enhanced physical downlink control channel, epdcch, comprising:

arranging physical resource sets of the sEPDCCH in the same group of Physical Resource Block (PRB) pairs in a time domain, wherein each physical resource set represents the length of a respective Transmission Time Interval (TTI);

setting the TTI length represented by each physical resource set to be equal to the TTI length of a corresponding Physical Downlink Shared Channel (PDSCH) and a corresponding Physical Uplink Shared Channel (PUSCH), wherein each physical resource set is used for scheduling the corresponding PDSCH and PUSCH; and

transmitting downlink control information, DCI, with at least one set of physical resources to cause a terminal device, UE, to obtain transmission time interval, TTI, lengths of a physical downlink shared channel, PDSCH, and a physical uplink shared channel, PUSCH, corresponding to the set of physical resources.

2. The method of claim 1, wherein setting the TTI length represented by each set of physical resources equal to the TTI length of a corresponding physical downlink shared channel, PDSCH, and a corresponding physical uplink shared channel, PUSCH comprises:

the start and end orthogonal frequency division multiplexing symbols OS and OS of each physical resource set are set to be aligned with the start and end OS of the corresponding PDSCH and the corresponding PUSCH, respectively.

3. The method of claim 1, further comprising:

predefining a search space carrying DCI in the set of physical resources of the sEPDCCH.

4. The method of claim 3, wherein predefining search spaces carrying DCI in the set of physical resources of the sEPDCCH comprises:

and limiting the number of candidate positions for carrying the DCI in the physical resource set of the sEPDCCH.

5. The method of claim 4, wherein defining the number of candidate positions for carrying the DCI in the set of physical resources of the sEPDCCH comprises:

defining a number of candidate locations for each set of physical resources to carry the DCI.

6. The method of claim 4, wherein defining the number of candidate positions for carrying the DCI in the set of physical resources of the sEPDCCH comprises:

and reserving the number of candidate positions for bearing the DCI for the combination of physical resource sets with different TTI lengths.

7. The method of claim 3, wherein predefining search spaces carrying DCI in the set of physical resources of the sEPDCCH comprises:

defining a priority of candidate locations carrying the DCI in the set of physical resources.

8. The method of claim 3, wherein predefining search spaces carrying DCI in the set of physical resources of the sEPDCCH comprises:

only the set of physical resources with the requested TTI length is triggered.

9. The method of claim 3, wherein predefining search spaces carrying DCI in the set of physical resources of the sEPDCCH comprises:

a starting OS is defined for the set of physical resources.

10. The method of claim 1, further comprising:

performing UE-specific configuration of the set of physical resources of the sEPDCCH using radio resource control, RRC, signaling.

11. The method of claim 10, wherein the UE-specific configuration comprises:

an ID of the set of physical resources, a mode of the assigned PRB pair, a starting OS, information of a reference signal for demodulation, a configuration of a PUCCH, and channel state information CSI of zero power.

12. A method for transmitting a short enhanced physical downlink control channel, epdcch, comprising:

receiving downlink control information, DCI, transmitted with at least one set of physical resources of the sEPDCCH; and

blind decoding the DCI to obtain the Transmission Time Interval (TTI) lengths of a Physical Downlink Shared Channel (PDSCH) and a Physical Uplink Shared Channel (PUSCH) corresponding to the physical resource set;

wherein the physical resource sets of the epdcch are arranged in the same set of PRB-pairs in the time domain, wherein each physical resource set represents a respective TTI length; and a TTI length represented by each set of physical resources for scheduling the corresponding PDSCH and PUSCH is set to be equal to a TTI length of the corresponding PDSCH and the corresponding PUSCH.

13. The method of claim 12, wherein blind decoding the DCI comprises:

blind decoding in a predefined search space carrying DCI in the set of physical resources of the sEPDCCH.

14. The method of claim 12, wherein blind decoding the DCI comprises:

blind decoding according to the UE-specific configuration of the received set of physical resources of the epdcch.

15. The method of claim 14, wherein the UE-specific configuration comprises:

16. An apparatus for transmitting a short enhanced physical downlink control channel, epdcch, comprising:

a first configuration unit configured to arrange physical resource sets of the epdcch in a same set of physical resource block, PRB, pairs in the time domain, wherein each physical resource set represents a respective transmission time interval, TTI, length;

a second configuration unit configured to set a TTI length represented by each set of physical resources to be equal to a TTI length of a corresponding physical downlink shared channel PDSCH and a corresponding physical uplink shared channel PUSCH, wherein each set of physical resources is used for scheduling the corresponding PDSCH and PUSCH; and

a transmitting unit configured to transmit downlink control information, DCI, with at least one set of physical resources of the epdcch to cause a terminal device, UE, to obtain transmission time interval, TTI, lengths of a physical downlink shared channel, PDSCH, and a physical uplink shared channel, PUSCH, corresponding to the set of physical resources.

17. The apparatus of claim 16, wherein the second configuration unit is further configured to:

the start OS and the end OS of each set of physical resources are set to align with the start OS and the end OS of the corresponding PDSCH and the corresponding PUSCH, respectively.

18. The apparatus of claim 16, further comprising a predefining unit configured to predefine a search space carrying DCI in the set of physical resources of the epdcch.

19. The apparatus of claim 18, wherein the predefined unit is further configured to:

20. The apparatus of claim 19, wherein the predefined unit is further configured to:

21. The apparatus of claim 19, wherein the predefined unit is further configured to:

22. The apparatus of claim 18, wherein the predefined unit is further configured to:

23. The apparatus of claim 18, wherein the predefined unit is further configured to:

only the set of physical resources with the requested TTI length is triggered.

24. The apparatus of claim 18, wherein the predefined unit is further configured to:

a starting OS is defined for the set of physical resources.

25. The apparatus of claim 16, further comprising an execution unit configured to perform UE-specific configuration of the set of physical resources of the epdcch using radio resource control, RRC, signaling.

26. The apparatus of claim 25, wherein the UE-specific configuration comprises:

27. An apparatus for transmitting a short enhanced physical downlink control channel, epdcch, comprising:

a receiving unit configured to receive downlink control information, DCI, transmitted using at least one set of physical resources of the sEPDCCH; and

a decoding unit configured to blind decode the DCI to obtain a Physical Downlink Shared Channel (PDSCH) corresponding to the set of physical resources and a Transmission Time Interval (TTI) length of a corresponding Physical Uplink Shared Channel (PUSCH);

28. The apparatus of claim 27, wherein the decoding unit is further configured to:

29. The apparatus of claim 27, wherein the decoding unit is further configured to:

blind decoding is performed according to the UE-specific configuration of the received physical resource set of EPDCCH.

30. The apparatus of claim 29, wherein the UE-specific configuration comprises: