CN107046713B

CN107046713B - Method and device for determining downlink control channel, terminal and base station

Info

Publication number: CN107046713B
Application number: CN201610082245.2A
Authority: CN
Inventors: 石靖; 夏树强; 张雯; 韩祥辉; 任敏; 张文峰
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2016-02-05
Filing date: 2016-02-05
Publication date: 2022-12-02
Anticipated expiration: 2036-02-05
Also published as: CN107046713A; WO2017133340A1

Abstract

The invention provides a method and a device for determining a downlink control channel, a terminal and a base station, wherein the method for determining the downlink control channel comprises the following steps: the terminal receives a downlink control channel bearing downlink control information in a short TTI, wherein the downlink control channel is located in a first control region or a second control region, when the downlink control channel is located in the first control region, the number of candidate sets of the downlink control channel in the short TTI is smaller than or equal to the number of candidate sets of a subframe in LTE, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is smaller than or equal to the number of candidate sets of X subframes in LTE, wherein X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1. By adopting the technical scheme provided by the invention, the problem that the existing downlink control channel cannot well support the low-delay requirement is solved.

Description

Method and device for determining downlink control channel, terminal and base station

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for determining a downlink control channel, a terminal, and a base station.

Background

With the increasing improvement of the fourth Generation mobile communication technology (4 g, the 4th Generation mobile communication technology) Long Term Evolution (LTE, long-Term Evolution)/Long Term Evolution advanced (LTE-Advance/LTE-a, long-Term Evolution Advance) system business, the technical index requirements for the next Generation mobile communication technology, i.e., the fifth Generation mobile communication technology (5g, the 5th Generation mobile communication technology), are also increasing. It is widely accepted in the industry that next generation mobile communication systems should have the characteristics of ultra-high speed, ultra-high capacity, ultra-high reliability, and ultra-low delay transmission characteristics. For the index of ultra-low delay in the 5G system, the currently accepted order of magnitude is that the air interface delay is about 1 ms.

In the related art, there is a method for realizing ultra-low latency by reducing a Transmission Time Interval (TTI) of the LTE system, and sufficiently shortening a processing latency unit to support the characteristic requirement of the 1ms air interface latency. At present, there are two methods for reducing TTI, one is to reduce the duration of a single OFDM symbol by expanding the subcarrier spacing of an Orthogonal Frequency Division Multiplexing (OFDM) system, and the method is involved in both a 5G high Frequency communication system and an ultra-dense network; another approach is to reduce the TTI length by reducing the number of OFDM symbols in a single TTI as discussed in the current third Generation Partnership project (3 gpp), which has the advantage of being fully compatible with existing LTE systems.

In the existing LTE system, a Downlink Control Channel (PDCCH) occupies a resource region of first 0-4 OFDM symbols in a system bandwidth, and an Enhanced Downlink Control Channel (EPDCCH) uses a part of a PRB resource region in a Downlink data traffic Channel (PDSCH). Compared with the existing subframe with the TTI length of 1ms, the shortened TTI containing less OFDM symbols is used as the TTI with the new granularity, and the existing downlink control channel cannot well support the TTI with the new granularity.

Aiming at the problem that the existing downlink control channel cannot well support the low-delay requirement in the related technology, an effective solution is not provided yet.

Disclosure of Invention

In order to solve the above technical problem, embodiments of the present invention provide a method and an apparatus for determining a downlink control channel, a terminal, and a base station.

According to an aspect of the present invention, a method for determining a downlink control channel is provided, including:

the method comprises the steps that a terminal receives a downlink control channel which bears downlink control information in a short transmission time interval TTI, wherein the downlink control channel is located in a first control region or a second control region, when the downlink control channel is located in the first control region, the number of candidate sets of the downlink control channel in the short TTI is smaller than or equal to the number of candidate sets of subframes in a long term evolution system LTE, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is smaller than or equal to the number of candidate sets of X subframes in the LTE, wherein X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

Further, before the terminal receives the downlink control channel carrying the downlink control information in the short transmission time interval TTI, the method further includes:

detecting a downlink control channel carrying the downlink control information in a control region in a short TTI, wherein the control region comprises at least one of the following: a first control area containing multiple candidate positions, a second control areaControllingThe region contains only one candidate location.

Further, detecting a downlink control channel carrying downlink control information in a control region in a short TTI includes:

receiving the downlink control channel in the first control region by detecting a plurality of candidate locations; or

Receiving the downlink control channel in the second control region by detecting the determined one candidate position.

Further, detecting a downlink control channel carrying the downlink control information in a control region in a short TTI includes:

detecting in the control region of all short TTIs; or

Detecting in a control region of a partial short TTI, wherein the partial short TTI is determined by: determining the partial short TTI through the configuration of the base station, wherein the configuration signaling configured by the base station comprises at least one of the following: a system message block SIB, a radio resource control RRC and downlink control information DCI; presetting the partial short TTI; and implicitly determining the detected short TTI according to the cell identifier ID or the terminal identifier UE ID or the cell radio network temporary identifier C-RNTI.

Further, the method further comprises:

at the time of detection of the second control region, the detection position of the short TTI and the position of the short PDCCH within the short TTI are determined by at least one of the following methods: determined by UE ID or C-RNTI; the downlink control indication DCI or RRC indicates the downlink control indication.

Further, when indicating by using the DCI, indicating by a first stage of the two stages of the DCI, where the first stage includes: a common or unchanged signaling bit field, and a detection location of a second-level DCI, the first-level DCI being located in a first control region, the second-level DCI being located in a second control region.

Further, the first-level DCI is located in a first short TTI in a group of short TTIs, and the second-level DCI determines, according to the first-level DCI, that the second-level DCI is located in one or more short TTIs in the group of short TTIs.

Further, the control region occupies short TTI resources by at least one of:

the control region and a short Physical Downlink Shared Channel (PDSCH) are subjected to time division multiplexing and occupy independent X Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein the short TTI comprises N OFDM symbols, X and N are positive integers, and X is less than or equal to N;

the control area occupies partial resources of X OFDM symbols, wherein the position of occupying the partial resources of the OFDM symbols is determined by a configuration signaling which is configured in advance or issued by a base station, and the configuration signaling comprises: short control format indication SCFI information in a high-level signaling system message block SIB or physical layer signaling;

the control region and a short Physical Downlink Shared Channel (PDSCH) are subjected to frequency division multiplexing, and partial short Physical Resource Block (PRB) resources are occupied; the position of occupying part of the short PRB resources is determined by a pre-configuration mode or a configuration signaling mode issued by a base station, and the configuration signaling comprises at least one of the following: the cell public signaling SIB and UE special signaling radio resource control RRC.

Further, the control region occupies partial resources of X OFDM symbols, including:

occupying part of the frequency domain resources in a specified order for at least one of the following frequency domain resources: short PRB, XPRB, resource block group RBG, wherein, appointed order includes: occupying to a configured frequency domain resource serial number from the designated serial number of the frequency domain resource, wherein an XPRB is an XPRB formed by M short PRBs in the short TTI, and M is a positive integer;

selecting one of predefined S resource regions by a base station, and configuring the selected resource region as the control region, wherein each resource region in the S resource regions contains a plurality of continuous or discontinuous short PRBs, and the number S of the resource regions comprises: 2 to the power E, wherein E is a positive integer.

Further, the short CFI information is carried by a short physical control format indicator channel PCFICH channel, and a manner of the short PCFICH channel occupying a resource location includes: in the first OFDM symbol in all or the first short TTI in a group of short TTIs, a transmission is punctured and a fixed position control channel element CCE or resource element set REG or resource block RE is used.

Further, the number of the following resources occupied by the control area is a fixed value or is configured by the base station through a designated signaling: XPRB, short PRB, RBG, wherein, appointed signalling includes: SIB, RRC, short CFI.

Further, the short CCE used by the short PDCCH includes: when the short CCE consists of short REGs, selecting short REGs with the same interval to form the short CCE, or the short CCE occupies one or more short PRBs.

Further, the REs occupied by the short REG pairs are numbered 0 to i in the order of frequency domain first and time domain second or time domain first and frequency domain second, and resource blocks with the same number are selected as a short REG, wherein the REs occupied by the short REG pairs are the rest of the REs except the REs occupied by the pilot in the short PRB or XPRB.

Further, when the downlink control channel is located in the first control region, the determination manner of the candidate set number of each short TTI at least includes one of the following:

in a group of short TTIs, the number of candidate sets in each short TTI is the same, and the candidate sets are determined according to the total number of divided X subframes;

distributing the quantity of the candidate sets according to the duration proportion of a group of short TTIs or the OFDM number proportion contained in the group of short TTIs;

within a group of short TTIs, the number of candidate sets in one or more short TTIs is greater than the number of candidate sets in the remaining short TTIs.

Further, when the downlink control channel is located in the second control region, determining a detection position of the short PDCCH in the short TTI according to the UE ID or the C-RNTI, wherein the detection position is determined at least by one of the following ways:

determining a first candidate set as a unique detection position in a search space in a short TTI;

determining a first candidate set as a unique detection position in a search space in a short TTI, and the first candidate set determined in a group of short TTIs is the same in position;

the short PDCCH occupies a fixed size resource as the detection location, wherein the detection location is predefined or determined by RRC signaling.

Further, the short TTIs of different terminals occupy different short PRBs or different OFDM symbols.

Further, the aggregation level corresponding to the downlink control channel includes: a fixed one or more aggregation levels, one or more aggregation levels configured by a base station, wherein the aggregation level is selected from the set L = {1, 2, 4, 8, 16, 24, 32}.

Further, when the downlink control channel is multiplexed and scrambled within a short TTI, the initial value of the scrambling sequence is determined at least by the sequence number of the short TTI, where the sequence number of the short TTI at least includes one of: sequence number in 1ms subframe, sequence number in radio frame.

According to another aspect of the present invention, there is also provided a method for determining a downlink control channel, including:

the method comprises the steps that a base station transmits downlink control information to a terminal through a downlink control channel in a short Transmission Time Interval (TTI), wherein the downlink control channel is located in a first control region or a second control region, when the downlink control channel is located in the first control region, the number of candidate sets of the downlink control channel in the short TTI is smaller than or equal to the number of candidate sets of subframes in a Long Term Evolution (LTE) system, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is smaller than or equal to the number of candidate sets of X subframes in the LTE, wherein X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

According to another aspect of the present invention, there is also provided a device for determining a downlink control channel, which is applied to a terminal, and includes:

a receiving module, configured to receive a downlink control channel carrying downlink control information in a short transmission time interval TTI, where the downlink control channel is located in a first control region or a second control region, and when the downlink control channel is located in the first control region, a number of candidate sets of the downlink control channel in the short TTI is less than or equal to a number of candidate sets of subframes in a long term evolution system LTE, or a sum of a number of candidate sets of each short TTI included in X subframes of the downlink control channel is less than or equal to a number of candidate sets of X subframes in LTE, where X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

According to another aspect of the present invention, there is provided a downlink control channel determining apparatus, applied to a base station, including:

a transmission module, configured to transmit downlink control information to a terminal through a downlink control channel in a short transmission time interval TTI, where the downlink control channel is located in a first control region or a second control region, and when the downlink control channel is located in the first control region, a number of candidate sets of the downlink control channel in the short TTI is less than or equal to a number of candidate sets of subframes in a long term evolution system LTE, or a sum of numbers of candidate sets of short TTIs included in X subframes of the downlink control channel is less than or equal to a number of candidate sets of X subframes in the LTE, where X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

According to another aspect of the present invention, there is also provided a terminal, including the apparatus for determining a downlink control channel described above.

According to another aspect of the present invention, there is also provided a base station, including the above-mentioned downlink control channel determining apparatus.

According to the invention, a first control region or a second control region is determined as a downlink control channel for sending downlink control information, when the downlink control channel is located in the first control region, the number of candidate sets of short TTIs of the downlink control channel is less than or equal to the number of candidate sets of subframes in LTE, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is less than or equal to the number of candidate sets of X subframes in LTE, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in short TTIs is equal to 1.

Drawings

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

fig. 1 is a flowchart of a method for determining a downlink control channel according to an embodiment of the present invention;

fig. 2 is a schematic diagram of short PDCCH occupying OFDM symbols independently with short PDSCH time division multiplexing in short TTI according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating that a short PDCCH occupies part of the resources of an OFDM symbol in a short TTI according to an embodiment of the present invention;

fig. 4 is a schematic diagram illustrating a manner in which a short REG occupies resources in a short TTI according to an embodiment of the present invention;

fig. 5 is a schematic diagram illustrating a manner in which short CCEs occupy resources in a short TTI according to an embodiment of the present invention;

fig. 6 is another flowchart of a method for determining a downlink control channel according to an embodiment of the present invention;

fig. 7 is a block diagram of a device for determining a downlink control channel according to an embodiment of the present invention;

fig. 8 is another block diagram of a downlink control channel determining apparatus according to an embodiment of the present invention;

fig. 9 is a block diagram of another structure of a device for determining a downlink control channel according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating that a short PDCCH occupies part of resources of an OFDM symbol in a short TTI in accordance with a preferred embodiment of the present invention;

fig. 11 is a schematic diagram of the short PDCCH occupying part of the short PRB resources in the short TTI in frequency division multiplexing with the short PDSCH according to the preferred embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the drawings and embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In an embodiment of the present invention, a method for determining a downlink control channel is further provided, and fig. 1 is a flowchart of the method for determining a downlink control channel according to the embodiment of the present invention, as shown in fig. 1, including the following steps:

step S102, a terminal receives downlink control channel transmission for bearing downlink control information in a short TTI, wherein the downlink control channel is located in a first control region or a second control region, when the downlink control channel is located in the first control region, the number of candidate sets of the downlink control channel in the short TTI is less than or equal to the number of candidate sets of subframes in a long term evolution system (LTE), or the sum of the number of candidate sets of each short TTI included in X subframes of the downlink control channel is less than or equal to the number of candidate sets of X subframes in the LTE, wherein X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

Through an interaction process between a terminal and a base station, a first control region or a second control region is determined as a downlink control channel for sending downlink control information, when the downlink control channel is located in the first control region, the number of candidate sets of short TTIs of the downlink control channel is smaller than or equal to the number of candidate sets of subframes in LTE, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is smaller than or equal to the number of candidate sets of X subframes in LTE, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTIs is equal to 1.

Optionally, before receiving downlink control information transmitted by the base station according to the downlink control channel in the short transmission time interval TTI, the following technical scheme may be further performed: detecting a downlink control channel carrying downlink control information in a control region in a short TTI, wherein the control region comprises at least one of the following: the method comprises a first control area and a second control area, wherein the first control area contains a plurality of candidate positions, the second area only contains one candidate position, and the control area in the short TTI detects a downlink control channel carrying downlink control information, wherein the following two conditions mainly exist: receiving the downlink control channel in a first control region by detecting a plurality of candidate locations; or receiving the downlink control channel in the second control area through the determined candidate position; or detecting a downlink control channel carrying downlink control information in a control region in a short TTI, which may further include the following two cases: detecting in the control region of all short TTIs; or in a control region of a partial short TTI, wherein the partial short TTI is determined by: determining the partial short TTI through the configuration of the base station, wherein the configuration signaling configured through the base station comprises at least one of the following: a system message block SIB, a radio resource control RRC and downlink control information DCI; presetting the partial short TTI; specifically, the detected short TTI may be implicitly determined according to the cell identity ID or the terminal identity UE ID or the cell radio network temporary identity C-RNTI, and when the DCI configuration is used, the DCI may be transmitted in a specific TTI, for example, in a first short TTI of a group of short TTIs, and when the second control region is detected, the detection position of the short TTI and the position of the short PDCCH within the short TTI are determined by at least one of the following methods: determined by UE ID or C-RNTI; and indicating DCI or RRC by downlink control indication.

In an alternative example of the embodiment of the present invention, the control region occupies the short TTI resources at least by one of the following ways: the control region and the short PDSCH are subjected to time division multiplexing and occupy independent X orthogonal frequency division multiplexing OFDM symbols, wherein the short TTI comprises N OFDM symbols, X and N are positive integers, and X is smaller than or equal to N; the control region occupies partial resources of X OFDM symbols, wherein the position of occupying partial resources of the OFDM symbols is determined by a pre-configuration or a configuration signaling issued by a base station, and the configuration signaling comprises the following steps: short CFI information in a high-level signaling system message block SIB or physical layer signaling; the control region and the short PDSCH are subjected to frequency division multiplexing, and partial short Physical Resource Block (PRB) resources are occupied; the position of occupying part of the short PRB resources is determined by a pre-configuration mode or a configuration signaling mode issued by a base station, and the configuration signaling comprises at least one of the following: the cell public signaling SIB and UE proprietary signaling RRC.

Further, the control region occupies partial frequency domain resources of X OFDM symbols, which can be implemented by the following technical scheme: occupying part of the frequency domain resources in a specified order for at least one of the following frequency domain resources: short PRB, XPRB, resource block group RBG, wherein, above-mentioned appointed order includes: occupying to a configured frequency domain resource serial number from the specified serial number of the frequency domain resource, wherein the XPRB is an XPRB formed by M short PRBs in the short TTI, and M is a positive integer; selecting one of predefined S resource regions by a base station, and configuring the selected resource region as the control region, wherein each resource region in the S resource regions includes a plurality of continuous or discontinuous short PRBs, and the number S of the resource regions includes: the power E of 2 is positive integer, namely S comprises 2, 4, 8, 16, \ 8230 \ 8230: \ 8230128.

In the following, the above technical solution is described with reference to an example, where a control region in a short TTI detects a downlink control channel carrying downlink control information, and the detection includes at least one of: blindly detecting a downlink control channel in a control area shared by multiple terminals; a downlink control channel is received and detected in a control region used by the terminal alone.

It should be noted that the first letter S of the english abbreviation in the embodiment of the present invention may also be understood as the abbreviation of short, but not limited to the understanding of all the english abbreviations.

The downlink control channel may also be referred to as an SPDCCH (Short PDCCH), the Short TTI is a TTI shorter than 1ms, and for the LTE system, the Short TTI is composed of N OFDM symbols, and the number N of the OFDM symbols included is at least one of {1, 2, 3, 4, 5, 6, and 7 }.

Further, the terminal detects the downlink control channel carrying the downlink control information in the control region in the short TTI, which can be implemented by the following scheme: detection in all short TTIs; the detection in part of the short TTIs specifically comprises: detecting in a short TTI configured by a base station; the configuration of the base station includes using SIB or RRC signaling to configure, and configuring the terminal at a certain period to perform detection in any number or limited set number of short TTIs in the period. (2) detection in a predefined or fixed short TTI. For example, the short TTIs are divided by 2 OFDM symbols, and the base station configures by RRC signaling which TTIs of the 70 short TTIs in the 10ms period need to be detected by a terminal using 70 bits.

The resource usage mode of the SPDCCH in the short TTI includes a Time Division Multiplexing (TDM) mode, a Frequency Division Multiplexing (FDM) mode, wherein the FDM mode configures a part of short PRBs occupied by the eNB, the TDM mode occupies an independent OFDM symbol or occupies a part of resources of the OFDM symbol, and the part of resources occupied by the OFDM symbol is notified of a Frequency band position occupied by the SPDCCH by the CFI.

When TDM is occupied: when the SPDCCH uses resources in a short TTI in a TDM mode, the SPDCCH region occupies the first X OFDM symbols in the system bandwidth or is used for the first X OFDM symbols in the short TTI bandwidth (less than the system bandwidth). Wherein, if the short TTI comprises N OFDM symbols, X is less than or equal to N, and the value of X is preferably 1. The value of X may be fixed or configured by the base station, and fig. 2 is a schematic diagram of the short PDCCH and the short PDSCH time division multiplexing independently occupying OFDM symbols in the short TTI according to the embodiment of the present invention; as shown in fig. 2, in the bandwidth occupied by the short TTI, the SPDCCH region occupies the first OFDM symbol in the short TTI. And when the resources in the short TTI are overlapped with the Legacy PDCCH regions, legacy PDCCH transmission is prioritized (a control channel or a service channel in the short TTI is transmitted by using the resources in part of Legacy PDCCHs in the suboptimal selection).

In this embodiment of the present invention, the short CFI information is carried by a short physical control format indicator channel PCFICH channel, and a manner of the short PCFICH channel occupying a resource location includes: in all of a group of short TTIs or in a first OFDM symbol in a first short TTI, a control channel element CCE or a resource element set REG or a resource block RE of a fixed location is punctured for transmission and used, and the number of resources occupied by the control region is a fixed value or is configured by a base station through a designated signaling: x PRB, short PRB, RBG, wherein, above-mentioned appointed signaling includes: SIB, RRC, short CFI; the short CCE used for the short PDCCH includes: 2 short REGs, 4 short REGs, 8 short REGs, 16 short REGs, or the short CCE occupies a specified number of RE resources, and when the short CCE consists of short REGs, the short REGs at the same interval are selected to constitute the short CCE, or the short CCE occupies one or more short PRBs.

Further, the number of the REs occupied by the short REG pairs is 0 to i in frequency domain first and time domain second or frequency domain first and time domain second, and the resource blocks with the same number are selected as a short REG, wherein the REs occupied by the short REG pairs are the rest REs except the REs occupied by the pilot in the short PRB or XPRB.

A further improvement of the foregoing technical solution in the embodiments of the present invention is that, when the downlink control channel is located in the first control region, the determination manner of the candidate set number of each short TTI at least includes one of the following: in a group of short TTIs, the number of candidate sets in each short TTI is the same, and the candidate sets are determined according to the total number of divided X subframes; distributing the number of the candidate sets according to different time length proportions of a group of short TTIs; within a group of short TTIs, the number of candidate sets in one or more short TTIs is greater than the number of candidate sets in the remaining short TTIs.

When the downlink control channel is located in the second control region, determining a detection position of a short PDCCH in a short TTI according to a UE (user equipment) ID (identity) or a cell radio network temporary identity) C-RNTI (cell-radio network temporary identity), wherein the detection position is determined at least in one of the following ways: determining a first candidate set as a unique detection position in a search space in a short TTI; determining a first candidate set as a unique detection position in a search space in a short TTI, wherein the positions of the first candidate sets determined in a group of short TTIs are the same; the short PDCCH occupies a fixed size resource as the detection location, wherein the detection location is predefined or determined by RRC signaling.

The time domain detection position of the short TTI can be determined by the following technical scheme: all the short TTIs, the monitoring position determined by the base station configuration, and the detection position determined according to the UE ID or the C-RNTI, wherein the configuration signaling configured by the base station at least comprises one of the following: RRC or SIB, when DCI configuration is used, DCI is transmitted in a specific TTI, such as in the first short TTI in a set of short TTIs. When a non-blind detection mode is adopted, the detection position of the short TTI and the position of the short PDCCH in the short TTI are determined by at least one of the following modes: determined by UE ID or C-RNTI; and indicating DCI or RRC by downlink control indication.

In an embodiment of the present invention, when indicating using DCI, the indicating is performed by a first stage of the two stages of DCI, where the first stage includes: the first stage performs blind detection, the second stage does not perform blind detection, in order to adapt to delay requirements of different priorities, short TTIs of different terminals occupy different short PRBs or occupy different OFDM symbols, specifically, when DCI is used, the first stage may be a first stage of two-stage DCI, the first stage includes a common/unchanged signaling bit field and a specific detection position of the second stage DCI, and the second stage DCI includes a PDSCH scheduling parameter of UE-specific.

The first-stage DCI still needs blind detection, and the second-stage DCI does not need blind detection, so that all possible blind detection times/candidate sets can be allocated to the detection of the first-stage DCI. The location of the second level DCI is among the scheduled PDSCH locations. I.e., not exceeding the locations occupied by PDSCH, the first level DCI is located in the first TTI in a group of short TTIs, or in Legacy PDCCH region. The second level DCI is located in a fraction of the short TTIs in the set of short TTIs.

Further, the short PDCCH region occupies part of the frequency domain resources of the first X OFDM symbols, and the specifically occupied position of the frequency domain resources is configured by the base station, which can be understood as independently occupying X OFDM symbols, and preferably occupies the first continuous X OFDM symbols in the short TTI, but does not exclude the occupation of the second continuous X OFDM symbols, which is not limited in the implementation of the present invention.

Specifically, the base station configures partial frequency domain resources of the first X OFDM symbols in the system bandwidth, or configures partial frequency domain resources for the first X OFDM symbols in the short TTI bandwidth (smaller than the system bandwidth), fig. 3 is a schematic diagram of the SPDCCH according to the embodiment of the present invention occupying partial resources of the OFDM symbols in the short TTI, as shown in fig. 3, the configuration signaling used by the base station is carried by the SPCFICH, or is carried by the MIB, SIB, or RRC signaling.

The short PDCCH region occupies partial frequency domain resources of the first X OFDM symbols, and the method comprises at least one of the following modes:

(1) Starting from the lowest or the highest sequence number of sPRB/XPRB/RBG (in the following description, for example, sPRB) to occupy the sPRB sequence number configured to the base station, the configured sPRB sequence number is preferably selected from one of the sets { sPRB i1, sPRB i2, \8230;, sPRB ix }, and the number of elements in the set is preferably 2 or 4 or 8 or 16.

(2) The base station selects one of the predefined x resource regions to be configured as an SPDCCH region, wherein each resource region in the x resource regions comprises continuous (or discontinuous-secondary preferred) sPRB, and the number x of the resource regions is preferably 2 or 4 or 8 or 16. Each resource region contains the same (or different-less preferred) number of sPRBs. The sPRBs contained in each resource region do not overlap (or overlap-less preferred).

Wherein, the short PCFICH channel carries part of frequency domain resources of the first X OFDM symbols informed by the SCFI information, and the mode of occupying resource positions by the channel includes: puncturing transmission in all or the first OFDM symbol in the first short TTI in a group of short TTIs, and using CCE or REG or RE resources with fixed positions. Wherein the first OFDM symbol refers to the entire OFDM symbol in the system bandwidth, or an OFDM symbol configured for use in the short TTI bandwidth (which is less than the system bandwidth) (i.e., a truncated OFDM symbol). Wherein the fixed position is a CCE or REG or RE resource continuously or discretely selected in the frequency domain. The group of short TTIs is divided by X1 ms subframes according to the granularity of the short TTIs. Here, the specific number of the above-mentioned group of short TTIs relates to a specific division of short TTIs into several short TTIs with the same N or different numbers of { N1, N2, \8230; } OFDM symbols in X1 ms subframes, where X is a positive integer, N and { N1, N2, \8230; } are integers from 1 to 7; for example, a set of short TTIs is divided in a 1ms subframe, such as 4, 3, 4, 3 OFDM symbols for a total of 4 short TTIs for 14 OFDM symbols in a Normal Cyclic Prefix (NCP), or 7 short TTIs for 2 OFDM symbols; or a group of short TTIs is divided in a 2ms subframe, such as 7 short TTIs in granularity order of 4 OFDM symbols for 28 OFDM symbols at NCP.

The continuous selection is preferably continuously selected from the lowest or highest CCE or REG or RE number of the frequency domain position in the system bandwidth or the bandwidth used for short TTI. The discrete extraction preferably extracts a fixed number of CCE or REG or RE resources from the system bandwidth or at medium intervals in frequency domain position in the short TTI bandwidth.

The short PDCCH uses CCEs as control channel elements, the used aggregation level includes at least one of AL =1, 2, 4, and 8 CCEs, and in FDM: when the SPDCCH uses resources in a short TTI in an FDM mode, partial sPRB resources in the short TTI are used. The used sPRB resource position determining mode comprises the following steps: (1) configuring, by the eNB, the occupied portion of the srbs; (2) fixed or predefined sPRB positions. Wherein the meaning of sPRB can be interpreted as: and shortening the PRB pair in the LTE system by taking short TTI as a unit to obtain a basic unit. For example, when N =2, the srb includes 12 subcarriers in the frequency domain and 2 OFDM symbols in the time domain.

It should be noted that the aggregation level corresponding to the downlink control channel includes: a fixed one or more aggregation levels, one or more aggregation levels configured by the base station, wherein the aggregation levels are selected from the set L = {1, 2, 4, 8, 16, 24, 32}.

The short PDCCH region uses part of sPRB resources in short TTI, the minimum occupation unit is 1XPRB or sPRB or RBG, and Y XPRB or sPRB or RBG is actually occupied. Wherein, XPRB meaning explains: in short TTI, M sPRBs form XPRBs, the resource occupied by the XPRBs is the same as that of LTE PRB pair, if 168 REs (normal CP) are contained, namely the value of M is inversely proportional to the length of short TTI. For example: n =2, when M =7 srbs constitute 1 XPRB. The RBG is a resource block group, and the values of different system bandwidths are different.

The short TTI position of the SPDCCH is all short TTIs or partial short TTIs, wherein the partial short TTI position is determined through base station configuration, namely the SPDCCH is only available for the partial short TTI of the configuration part. The configuration signaling includes SIB or RRC.

And the frequency domain position of the SPDCCH uses XPRB or sPRB or RBG set as a fixed position or base station configuration, and the specific quantity is fixed or the base station configuration is carried out. The fixed mode comprises that all TTIs use the same frequency domain position or the frequency domain position of the SPDCCH in the short TTI is determined implicitly according to the short TTI index. The base station configuration mode can configure different frequency domain positions according to different short TTIs, or configure the same frequency domain position. The number of XPRB or sRB or RBG contained in the XPRB or sRB or RBG set is fixed or configured by the base station, and the number is preferably at least one of the set {1, 2, 4, 6, 8, 10 }. The configuration signaling comprises RRC or SIB; the SPDCCH described above uses SCCE as a control channel element, which contains 24 or 8 or 16 SREGs, or which directly uses a certain number of RE resources. SREG first takes the frequency domain and then the time domain with the number of 0-i in the pilot frequency occupying RE in the sPRB or XPRB, the SREG with the same number is taken as an SREG, and i takes the value of at least one of the set {1, 3, 7, 15 }. When the SCCE consists of SREGs, the SREGs are preferably selected at equal intervals to form the SCCE, and if the SREGs have 8 SREGs and the SCCE consists of 2 SREGs, the SCCE index 0 consists of SREG index 0 and SREG index 4.

For example, fig. 4 is a schematic diagram of a manner in which SREGs occupy resources in a short TTI according to an embodiment of the present invention, and as shown in fig. 4, a short TTI includes 4 OFDM symbols, where XPRB =3sprb, SREGs are numbered 0-7, and SREGs with the same number are used as one SREG. When there are 4 SCCEs in an XPRB, 2 SREGs constitute one SCCE, for example, SREG0 and SREG4 constitute SCCE0 according to the principle of selecting at equal intervals.

When the SCCE directly uses a certain number of RE resources, it is preferable that the SCCE occupies 1 srb or an integer multiple of the srb. Fig. 5 is a schematic diagram illustrating a manner in which SCCE occupies resources in a short TTI according to an embodiment of the present invention, and as shown in fig. 5, a short TTI includes 4 OFDM symbols, and SCCE occupies the entire sPRB in an XPRB. For another example, when the Short TTI contains 2 OFDM symbols, the SCCE occupies multiple srbs, e.g., 2 srbs.

In the embodiment of the invention, the blind test mode adopts a search space mode, and the total blind test times of a group of short TTI (transmission time interval) divided by X1 ms subframes according to the short TTI granularity are not more than the sum of the maximum blind test times of X1 ms subframes of LTE (long term evolution). For example: the sum of the number of short TTI candidate sets in a 1ms subframe does not exceed the number of candidate sets in an LTE 1ms subframe.

The determination mode of the candidate set quantity in each short TTI in the search space comprises at least one of the following modes:

(1) The number of candidate sets in each short TTI in a group of short TTIs is the same and is determined according to the total number of the divided X subframes of 1 ms. If the total number of candidate sets of X1 ms subframes is S, the number of candidate sets in each short TTI is S

And n represents the number of the divided short TTIs. For example: in NCP, taking UE-specific search space USS as an example, 7 short TTIs are divided by 1ms subframe (X = 1) according to short TTI granularity N =2, and the number of candidate sets in each short TTI is

And (4) respectively. Dividing a 2ms subframe (X = 2) into 7 short TTIs according to the short TTI granularity N =4, wherein the quantity of candidate sets in each short TTI is

And (4) respectively.

(2) The number of candidate sets is allocated according to different time length proportions of a group of short TTIs. If 4 short TTIs are divided in a 1ms subframe according to 4-3-4-3 OFDM symbols, and the number of candidate sets in each short TTI is proportionally distributed according to 4.

(3) The number of candidate sets in one or more short TTIs in a group of short TTIs is greater than the number of candidate sets in the remaining short TTIs. Preferably, the number of first short TTI candidate sets is greater than the number of subsequent short TTI candidate sets. For example: preferably, the search space of the first short TTI supports detection of first-level DCI of two-level DCI, or supports detection of both CSS and USS, and the search space of the subsequent short TTI supports detection of second-level DCI of two-level DCI, or supports detection of only USS. The two-stage DCI is master-slave DCI or fast-slow DCI. That is, the first-level DCI and the second-level DCI together constitute the completed scheduling control information, the first-level DCI includes a common control information part or an infrequently changed part, and the second-level DCI includes different scheduling information or a frequently changed part between UEs.

The aggregation level corresponding to the candidate set may be fixed or configured by the base station. The aggregation level preferably sets L = { at least one of 1, 2, 4, 8, 16, 24, 32} (E) CCEs/SCCEs. The configuration uses SIB or RRC.

Specifically, taking the USS as an example, 7 short TTIs are divided by 2 OFDM symbol granularity in 1ms, and the maximum blind detection times of the existing 1ms subframe is not exceeded. At this time, the maximum blind detection times within 1ms are not increased, the corresponding aggregation levels and the number of candidate sets need to be further limited, and 2 candidate sets exist in each short TTI according to the principle of equally dividing the candidate sets. For example: the aggregation level supports AL =1CCE only and the candidate set supports 2 per short TTI. In this case, the short TTI is considered to be used in a small coverage scenario, the channel quality is good, and a large aggregation level is not required.

K in the search space definition no longer represents the subframe sequence number but a short TTI sequence number, e.g. in a 1ms subframe, or in 1 radio frame, or,

the short TTI sequence number in a group of short TTIs divided by X1 ms subframes. L represents polymerization grade, M =0, \8230M ^(L) Representing a candidate set, N _CCE,k Indicating the number of CCEs in the short TTI index k, i =0, \ 8230;, L-1 indicates the CCE included in the aggregation level:

Y _k ＝(A·Y _k-1 )mod D

Y _-1 ＝n _RNTI ≠0,A＝39827,D＝65537and k＝n _TTI wherein Y is _k Indicates the starting position of the detection CCE in the short TTI # k.

For example, the search space candidate set is shown in table 1, where the aggregation level is exemplified by L =1CCE, and a specific aggregation level may be fixed or configured by the base station.

Table 1 SPDCCH candidate set

And in a non-blind detection mode, the unique SPDCCH detection position is determined according to the UE ID or the C-RNTI in short TTI, and blind detection is not performed any more. The method comprises the following steps: (1) Searching a first candidate set in the space, and iterating the first position of each TTI hash. (2) The first position of each TTI is the same, which is suitable when the whole OFDM symbol is used and the CFI indicates the partial frequency domain position of the OFDM symbol. (3) SPDCCH occupies a fixed size resource and UE-specific is uniquely determined.

Namely a non-blind detection mode, and the detected short TTI is configured by the base station or determined according to the UE ID or the C-RNTI. The configuration signaling is RRC or SIB. For example, for SPDCCH detection in USS, the detected short TTIs are not every short TTI, but which short TTIs are to be detected in a certain duration T ms are configured through RRC signaling, and (T/X) X (L/N) bits are used, where L is the number of OFDM symbols included in X1 ms subframes, and N represents the number of OFDM symbols included in a short TTI. Or the terminal implicitly determines the short TTI according to the UE ID or C-RNTI value and possible base station configuration related parameters. For example, the configured relevant parameters include a duration T and a density factor m, where the short TTI Index n detected in the duration T can be expressed as (taking C-RNTI as an example): n = C-RNTI mod ((T/X) × (L/N)/m). Where m may be a number greater than 0, such as at least one of the set {1/8, 1/6, 1/4, 1/2, 1, 2, 4, 8, 10 }. The duration T is preferably at least one of the set 10, 20, 40, 80.

For the blind detection scheme, in fact, blind detection candidate positions are already few in each short TTI, and are very close to non-blind detection. For the non-blind detection scheme, the terminal performs SPDCCH detection on the determined candidate set. I.e. at a certain candidate set position with a certain aggregation level and a certain candidate set.

The method comprises the following steps: still search space with Rel-8PDCCH and k = n _TTI And under the condition that L is fixed, the calculated CCE starting position is the only position for detecting the SPDCCH by the UE, and other candidate sets are not detected blindly. The aggregation level at this time is configured by RRC signaling using a fixed L =1CCE, or aggregation level L. The detection positions of different UEs are distinguished by C-RNTIs.

The method 2 comprises the following steps: the processing complexity is reduced and the processing time delay is reduced on the basis of the method 1. No more inter-TTI hash iterations, Y _k ＝n _RNTI And k = n _TTI . At this time, for the SPDCCH in the TDM-only manner, the calculated positions in each TTI are the same, and if the SPDCCHs of two UEs collide in a certain TTI, the SPDCCHs collide all the time (RNTI is unchanged and L is unchanged), and for the manner that the SPDCCH occupies a partial frequency domain position of 1 OFDM symbol, because the total CCE quantities of the TTIs are different, the two UEs collide in TTI i +1 without collision.

The method 3 comprises the following steps: SPDCCH occupies fixed size resources and UE-specific is uniquely determined. SPDCCH uses a fixed resource size, e.g., L CCEs, i.e., 9L REGs, in the first OFDM symbol, and considering processing simplicity, short TTI uses a total of N REGs in X MHz bandwidth to

Selecting 9 REGs at equal intervals to form 1CCE (control element sequence), wherein the total number is

And (4) CCEs. I.e. the detection position is

For example: in pure TDM mode, 20MHz bandwidth is used, 200 REGs (when there is CRS), L =1, 22 CCEs are counted, each CCE is formed by selecting 9 REGs at equal intervals according to step length of 22, and the specific position for detecting SPDCCH is n _RNTI modN _CCE,k ，k＝n _TTI . For the mode that the SPDCCH occupies 1 OFDM symbol partial frequency domain position, partial bandwidth is used, and the quantity of REGs and CCEs is determined according to the partial bandwidth.

In order to improve the above technical solution, in an embodiment of the present invention, a method for determining a downlink control channel is further provided, and fig. 6 is another flowchart of the method for determining a downlink control channel according to the embodiment of the present invention, as shown in fig. 6, including the following steps:

step S602: the method comprises the steps that a base station transmits downlink control information to a terminal through a downlink control channel in a short Transmission Time Interval (TTI), wherein the downlink control channel is located in a first control region or a second control region, when the downlink control channel is located in the first control region, the number of candidate sets of the downlink control channel in the short TTI is smaller than or equal to the number of candidate sets of subframes in a Long Term Evolution (LTE) system, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is smaller than or equal to the number of candidate sets of X subframes in the LTE, wherein X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

Through the interaction process of the base station and the terminal, a first control area or a second control area is determined as a downlink control channel for sending downlink control information, when the downlink control channel is located in the first control area, the number of candidate sets of short TTIs of the downlink control channel is less than or equal to the number of candidate sets of subframes in LTE, or the sum of the number of candidate sets of each short TTI contained in X subframes of the downlink control channel is less than or equal to the number of candidate sets of X subframes in LTE, and when the downlink control channel is located in the second control area, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

When the base station side sends the SPDCCH, multiplexing and scrambling of a plurality of short PDCCHs in a short TTI are allowed, and the multiplexing is carried out in a short TTI. When scrambling, short TTI or subframe is used as a unit, where the initial value of the scrambling sequence may specifically consider at least one of the following modes:

it should be noted that the short TTI sequence number includes at least one of the following: a sequence number within a 1ms subframe, a sequence number within a radio frame, e.g., TTI =2 OFDM, divides 7 short TTIs in a 1ms subframe. The sequence number of the short TTI in the 1ms subframe is 0-6, and the scrambling initial value determining mode comprises the following steps:

(1) In the existing mode, the method has the defects that,

-not distinguishing the scrambling sequence of the TTI within a subframe, but still distinguishing the scrambling sequence in units of subframes.

(2) On the basis of the TTI it is preferred that,

-distinguishing scrambling sequences of only 7 different TTIs in 1ms, nTTI =0,1, \8230;, 6.

(3) On the basis of the TTI it is possible to control,

-distinguishing scrambling sequences, n, for a total of 70 TTIs in a radio frame _TTI ＝0,1,…,6。

When TTI =2 OFDM, 7 short TTIs are divided in a 1ms subframe, the serial number of the short TTI in a radio frame is 0-69, and the scrambling initial value determining mode comprises the following steps:

on the basis of the TTI it is preferred that,

-distinguishing scrambling sequences, n, of a total of 70 TTIs in a radio frame _TTI ＝0,1,…,69。

On the basis of the TTI it is possible to control,

-differentiating only the scrambling sequences of 7 different TTIs in 1ms, n _TTI ＝0,1,…,69。

On the basis of the sub-frame,

-not distinguishing the scrambling sequence of the TTI within a subframe, still distinguishing the scrambling sequence in units of subframes.

To illustrate, the above is only 2 OFDM symbolsThe short TTI of number is an example and the method is similar for the remaining length of short TTIs of 1-7 symbols. For example, 2 short TTIs are divided by 7 OFDM symbols, and the 7 short TTIs are converted into 2 short TTIs, n _TTI Indicating 0,1 in a 1ms subframe or 0,1, \ 8230;, 19 in a radio frame.

For (1) - (3), when the short PDCCH occupies part of the SPRB in FDM fashion, for using UE-specific scrambling sequences, it will be

Is changed to

Where the parameter is configured by RRC, where m may always be 0, or m =0 or 1 and configured by the base station, representing a set of search spaces.

It should be noted that for simplicity of description, the above-mentioned method embodiments are shown as a series of combinations of acts, but those skilled in the art will recognize that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that acts and modules are not required to practice the invention.

In this embodiment, a device for determining a downlink control channel is further provided, which is applied to a terminal and is used to implement the foregoing embodiments and preferred embodiments, and details of the modules involved in the device are described below. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated. Fig. 7 is a block diagram of a device for determining a downlink control channel according to an embodiment of the present invention. As shown in fig. 7, the apparatus includes:

a receiving module 70, configured to receive a downlink control channel that carries downlink control information in a TTI, where the downlink control channel is located in a first control region or a second control region, and when the downlink control channel is located in the first control region, a candidate set number of the downlink control channel in a short TTI is less than or equal to a candidate set number of subframes in a long term evolution system LTE, or a sum of candidate set numbers of each short TTI included in X subframes of the downlink control channel is less than or equal to a candidate set number of X subframes in LTE, where X is a positive integer, and when the downlink control channel is located in the second control region, the candidate set number of the downlink control channel in the short TTI is equal to 1.

Through the action of the receiving module 70, a first control region or a second control region is determined as a downlink control channel for sending downlink control information, when the downlink control channel is located in the first control region, the number of candidate sets of short TTIs of the downlink control channel is less than or equal to the number of candidate sets of subframes in LTE, or the sum of the number of candidate sets of each short TTI included in X subframes of the downlink control channel is less than or equal to the number of candidate sets of X subframes in LTE, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in a short TTI is equal to 1.

Fig. 8 is another block diagram of a structure of an apparatus for determining a downlink control channel according to an embodiment of the present invention, where the apparatus further includes: a detecting module 72, configured to detect a downlink control channel carrying the downlink control information in a control region in a short TTI, where the control region includes: a first control area, a second control area, wherein the detecting module 72 includes: a first detecting unit 720, configured to blindly detect the downlink control channel in the first control region; or the second detecting unit 722 is configured to detect the downlink control channel in the second control region in a non-blind manner, in other words, the detecting module 72 includes: a third detecting unit 724 for detecting in the control regions of all short TTIs; or a fourth detecting unit 726, configured to detect in a control region of a partial short TTI, where the partial short TTI is determined by: determining the partial short TTI through the configuration of the base station; the partial short TTI is preset.

The embodiment of the invention also provides a terminal which comprises the device for determining the downlink control channel.

In this embodiment, a device for determining a downlink control channel is further provided, which is applied to a base station and is used to implement the foregoing embodiments and preferred embodiments, which have already been described and are not described again, and a description is provided below for modules involved in the device. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated. Fig. 9 is a block diagram of another structure of a device for determining a downlink control channel according to an embodiment of the present invention. As shown in fig. 9, the apparatus includes:

a transmission module 90, configured to transmit downlink control information to a terminal through a downlink control channel in a short transmission time interval TTI, where the downlink control channel is located in a first control region or a second control region, and when the downlink control channel is located in the first control region, a number of candidate sets of the downlink control channel in the short TTI is less than or equal to a number of candidate sets of subframes in a long term evolution system LTE, or a sum of a number of candidate sets of each short TTI included in X subframes of the downlink control channel is less than or equal to a number of candidate sets of X subframes in LTE, where X is a positive integer, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in the short TTI is equal to 1.

Through the action of the transmission module 90, a first control region or a second control region is determined as a downlink control channel for sending downlink control information, when the downlink control channel is located in the first control region, the number of candidate sets of short TTIs of the downlink control channel is less than or equal to the number of candidate sets of subframes in LTE, or the sum of the number of candidate sets of each short TTI included in X subframes of the downlink control channel is less than or equal to the number of candidate sets of X subframes in LTE, and when the downlink control channel is located in the second control region, the number of candidate sets of the downlink control channel in a short TTI is equal to 1.

The embodiment of the invention also provides a base station which comprises the device for determining the downlink control channel.

For better understanding of the above-mentioned determining procedure of the downlink control channel and the determining procedure of the downlink control channel, the following description is made in conjunction with the preferred embodiments, but is not intended to limit the scope of the present invention.

Preferred embodiment 1

And the base station loads downlink control information through the SPDCCH and sends the downlink control information to the UE, wherein the SPDCCH occupies resources in a short TTI in a TDM mode. In this embodiment, taking NCP network control protocol as an example, the short TTI includes 2 OFDM symbols, and 7 short TTIs are divided by 2 OFDM symbols in a 1ms subframe. Or 4 short TTIs are divided in the 1ms subframe according to the structure of 4-3-4-3 OFDM symbols. Or 7 short TTIs are divided by 4 OFDM symbols in a 2ms subframe.

The SPDCCH region occupies the first X OFDM symbols in the system bandwidth or is used for the first X OFDM symbols in the short TTI bandwidth (less than the system bandwidth). Wherein, if the short TTI comprises N OFDM symbols, X is less than or equal to N, and the value of X is preferably 1. The value of X may be fixed or configured by the base station. SPDCCH occupies the first OFDM symbol in the short TTI. Taking the short TTI containing 2 OFDM symbols as an example, the Bandwidth used by the short TTI is the system Bandwidth (all resources are used by short TTI users) or a part of the system Bandwidth (legacy UE and short TTI users respectively occupy a part of frequency domain resources in the system Bandwidth). Wherein, the resource overlapped with the Legacy PDCCH is preferentially used by the Legacy PDCCH.

At this time, when the SPDCCH and the PDCCH occupy 1 OFDM symbol, the resource granularity, the aggregation level, and the search space use the same structure. That is, CCEs composed of REGs are used as basic aggregation levels AL, a plurality of AL =1, 2, 4, 8 are available, and the specifically used aggregation levels are fixed or configured by the base station.

And when the base station side sends the SPDCCHs, multiplexing and scrambling a plurality of SPDCCHs in short TTI, wherein the multiplexing is carried out in the short TTI. The scrambling is performed in short TTI or sub-frame units, wherein the initial value of the scrambling sequence may specifically be considered to be determined based on TTI,

i.e. to distinguish scrambling sequences, n, of a total of 70 TTIs in a radio frame _TTI ＝0,1,…,6。

And carrying out layer mapping and precoding on the scrambled sequence by using QPSK modulation and using an SFBC transmission diversity transmission mode. And finally, when mapping to the resource unit, mapping to only the first OFDM symbol used by the SPDCCH in the short TTI.

And blind-detecting a possible candidate set in the USS in each short TTI when the terminal demodulates, or directly detecting the SPDCCH at the determined resource position by adopting a non-blind detection mode. The aggregation level in each short TTI supports AL =1CCE only and the candidate set supports 2 at blind detection. And at the moment, the UE determines the detection starting position in each short TTI according to the value of the C-RNTI of the UE. If the first position is not the own SPDCCH, the detection continues at the next candidate set position.

Y _k ＝(A·Y _k-1 )mod D

Y _-1 ＝n _RNTI ≠0,A＝39827,D＝65537and k＝n _TTI 。

For the non-blind detection mode, the terminal detects the SPDCCH in the short TTIs configured by the base station, for example, 10 short TTIs determined in 70 short TTIs configured by the base station in 10ms are detected. And the determined position is detected in a certain short TTI, for example, only the first candidate set position of the search space is detected, at this time, L is fixed to 1, and the SPDCCH of the terminal is determined according to the UE ID or the C-RNTI.

By the scheme of the embodiment, the SPDCCH is used in the short TTI in the TDM manner, so that each short TTI can use the downlink control channel and is simple to implement, and the cost is high. And the maximum blind detection times are reduced or a non-blind detection mode is adopted to reduce the complexity of the terminal while the time delay is reduced.

Preferred embodiment 2

And the base station carries downlink control information through the SPDCCH and sends the downlink control information to the UE, wherein the SPDCCH carries partial frequency domain resources of the first X OFDM symbols in the short TTI. In this embodiment, taking NCP as an example, the short TTI includes 2 OFDM symbols, and 7 short TTIs are divided by 2 OFDM symbols in a 1ms subframe. Or 4 short TTIs are divided in the 1ms subframe according to 4-3-4-3 OFDM symbol structures. Or 7 short TTIs are divided by 4 OFDM symbols in a 2ms subframe.

The SPDCCH region occupies the first X OFDM symbols in the system bandwidth or is used for the first X OFDM symbols in the short TTI bandwidth (less than the system bandwidth). If the short TTI comprises N OFDM symbols, X is less than or equal to N, and X preferably takes a value of 1. The value of X may be fixed or configured by the base station. SPDCCH occupies the first OFDM symbol in the short TTI. Taking an example that a short TTI includes 2 OFDM symbols, fig. 10 is a schematic diagram that an SPDCCH according to the preferred embodiment of the present invention occupies part of resources of OFDM symbols in the short TTI, as shown in fig. 10, at this time, a Bandwidth used by the short TTI is a system Bandwidth (all resources are used by short TTI users) or a part of the system Bandwidth (legacy UE and short TTI users respectively occupy a part of frequency domain resources in the system Bandwidth). The base station configures partial frequency domain resources of the first X OFDM symbols in the system bandwidth, or configures partial frequency domain resources of the first X OFDM symbols used in the short TTI bandwidth (smaller than the system bandwidth). Wherein, the configuration signaling used by the base station is carried through the SPCFICH. The SPCFICH channel carries SCFI information to inform partial frequency domain resources of the first X OFDM symbols, the mode of the channel occupying the resource position is to punch transmission in the first OFDM symbol in short TTI, and CCE or REG or RE resources with fixed positions are used. Wherein the fixed position is a CCE or REG or RE resource continuously or discretely selected in the frequency domain. For example, the 3 lowest-numbered REGs occupy the frequency domain location. The frequency domain resource of the first X OFDM symbols occupied by the SPDCCH region indicates a specifically occupied sPRB range by SCFI using 2 bits, the sPRB sequence number configured to the base station is occupied from the sPRB 0 with the lowest sPRB sequence number, and the configured sPRB sequence number is preferably selected from a set { sPRB 19, sPRB 39, sPRB 79 and sPRB 99} (system bandwidth 20 MHz) to configure the frequency domain range in the first OFDM symbol occupied by the SPDCCH in different short TTIs.

Wherein, the resource overlapped with the Legacy PDCCH is preferentially used by the Legacy PDCCH.

And when the base station side sends the SPDCCHs, multiplexing and scrambling a plurality of SPDCCHs in short TTI, wherein the multiplexing is carried out in the short TTI. Scrambling is performed in short TTI or sub-frame units, wherein the initial value of the scrambling sequence is determined based on TTI,

i.e. only distinguish the scrambling sequences of 7 different TTIs in 1ms, n _TTI ＝0,1,…,6。

And blind-detecting a possible candidate set in the USS in each short TTI when the terminal demodulates, or directly detecting the SPDCCH at the determined resource position by adopting a non-blind detection mode. The aggregation level in each short TTI supports only AL =1CCE and the candidate set supports 2 in blind detection. And at the moment, the UE determines the detection starting position in each short TTI according to the value of the C-RNTI of the UE. If the first position is not the own SPDCCH, the detection continues at the next candidate set position. In this case, the number of CCEs in the short TTI is different according to different SCFI configurations.

Y _k ＝(A·Y _k-1 )mod D

Y _-1 ＝n _RNTI ≠0,A＝39827,D＝65537and k＝n _TTI 。

For the non-blind detection mode, the terminal detects the SPDCCH in all short TTIs. And detects the determined position in the short TTI, e.g., only the first candidate set position of the search space, where L is fixed to 1, and determines that the SPDCCH for the terminal is based on the UE ID or C-RNTI. And no more inter-TTI hash iterations, Y _k ＝n _RNTI And k = n _TTI . For the mode that the SPDCCH occupies 1 OFDM symbol partial frequency domain position, because the total number of CCEs in each TTI is different, two UEs collide in TTI i +1 without collision.

By the scheme of the embodiment, the SPDCCH is used in the short TTI in the TDM optimization manner, so that each short TTI can use a downlink control channel and the control overhead is controllable, and the eNB configures the size of the SPDCCH region. And the maximum blind detection times are reduced or a non-blind detection mode is adopted to reduce the complexity of the terminal while the time delay is reduced.

Preferred embodiment 3

And the base station carries downlink control information through the SPDCCH and sends the downlink control information to the UE, and the SPDCCH occupies part of the sPRB in the short TTI. In this embodiment, taking NCP as an example, a short TTI includes 2 OFDM symbols, and a 1ms subframe is divided into 7 short TTIs by 2 OFDM symbols. Or 4 short TTIs are divided in the 1ms subframe according to the structure of 4-3-4-3 OFDM symbols. Or 7 short TTIs are divided by 4 OFDM symbols in a 2ms subframe.

The SPDCCH region occupies a part of the srbs. Taking the short TTI containing 2 OFDM symbols as an example, the minimum occupancy unit of SPDCCH is 1XPRB, and the search space is configured with XPRB set by the base station. ( XPRB meaning interpretation: in a short TTI, several sPRBs form an XPRB, and the resource occupied by the XPRB is preferably the same as that of an LTE PRB pair resource, for example: 1XPRB =7sPRB, N = 2. Or define XPRB size uniformly, such as 1xprb =10prb. )

The terminal detects SPDCCH in each short TTI. The detected frequency domain position is the frequency domain position configured by the base station, for example, the configured XPRB set contains 2 XPRBs and is located in

XPRB index

0 and 1. And within a certain duration (e.g. 40 ms), using the same configured XPRB set frequency domain location, fig. 11 is a schematic diagram of the SPDCCH occupying part of the srb resources in the short TTI in frequency division multiplexing with the SPDSCH.

At this time, the resource granularity, the aggregation level and the search space when the ECCE resources in the PRB set are occupied by the SPDCCH and the EPDCCH use the same structure. That is, ECCE formed by EREG is used as a basic aggregation level AL, a plurality of AL =1, 2, 4, 8, 16, 24, 32 are available, and a specific aggregation level used is fixed or configured by a base station.

And when the base station side sends the SPDCCHs, multiplexing and scrambling a plurality of SPDCCHs in short TTI, wherein the multiplexing is carried out in the short TTI. Scrambling is performed in short TTI or sub-frame units, where the scrambling sequence initial value is determined based on TTI,

And carrying out layer mapping and precoding on the scrambled sequence by using QPSK modulation, open-loop/closed-loop precoding or a space diversity transmission mode. And finally, mapping to the SCCE(s) used by the SPDCCH in the XPRB set when mapping to the resource element.

And blind detecting a possible candidate set in the USS in each short TTI when the terminal demodulates, or directly detecting the SPDCCH at the determined resource position by adopting a non-blind detection mode. The aggregation level in each short TTI supports only AL =1CCE and the candidate set supports 2 in blind detection. And at the moment, the UE determines the detection starting position in each short TTI according to the value of the C-RNTI of the UE. If the first position is not the own SPDCCH, the detection continues at the next candidate set position. In this case, the number of CCEs in the short TTI is different according to different SCFI configurations.

For the non-blind detection mode, the terminal detects the SPDCCH in all short TTIs. And detects the determined location in the short TTI, e.g. only the first candidate set location of the search space, when L is fixed to 1, which is determined to be the terminal based on the UE ID or C-RNTISPDCCH of the end. And no more inter-TTI hash iterations, Y _k ＝n _RNTI And k = n _TTI 。

By the scheme of the embodiment, the SPDCCH is used in the short TTI in the FDM manner, so that each short TTI can flexibly use the downlink control channel and the control overhead is controllable, and the eNB configures the size of the SPDCCH region. And the maximum blind detection times are reduced or a non-blind detection mode is adopted to reduce the complexity of the terminal while the time delay is reduced.

In summary, the technical solution of the embodiment of the present invention can achieve the following technical effects: the method solves the problem of using the downlink control channel in the new-granularity short TTI containing fewer OFDM symbols, can reduce the detection complexity, can correspondingly obtain shorter RTT time delay under the condition of the new-granularity short TTI, and meets the requirement of low-time-delay communication.

In another embodiment, a software is provided, which is used to execute the technical solutions described in the above embodiments and preferred embodiments.

In another embodiment, a storage medium is provided, in which the software is stored, and the storage medium includes but is not limited to: optical disks, floppy disks, hard disks, erasable memories, etc.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the objects so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized in a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a memory device and executed by a computing device, and in some cases, the steps shown or described may be executed out of order, or separately as individual integrated circuit modules, or multiple modules or steps thereof may be implemented as a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining a downlink control channel, comprising:

2. The method of claim 1, wherein before the terminal receives a downlink control channel carrying downlink control information in a short Transmission Time Interval (TTI), the method further comprises:

detecting a downlink control channel carrying the downlink control information in a control region in a short TTI, wherein the control region comprises at least one of the following: the device comprises a first control area and a second control area, wherein the first control area contains a plurality of candidate positions, and the second control area only contains one candidate position.

3. The method of claim 2, wherein detecting a downlink control channel carrying downlink control information in a control region in a short TTI comprises:

4. The method of claim 2, wherein detecting the downlink control channel carrying the downlink control information in a control region in a short TTI comprises:

detecting in the control region of all short TTIs; or

Detecting in a control region of a partial short TTI, wherein the partial short TTI is determined by: determining the partial short TTI through the configuration of the base station, wherein the configuration signaling configured by the base station comprises at least one of the following: a system message block SIB, a radio resource control RRC and downlink control information DCI; presetting the partial short TTI; and implicitly determining the detected short TTI according to the cell identification ID or the terminal identification UE ID or the cell radio network temporary identification C-RNTI.

5. The method of claim 4, further comprising:

at the time of detection of the second control region, the detection position of the short TTI and the position of the short PDCCH within the short TTI are determined by at least one of: determined by UE ID or C-RNTI; and indicating DCI or RRC by downlink control indication.

6. The method of claim 5, wherein when indicating using DCI, indicating is performed by a first of two levels of the DCI, wherein the first level comprises: a common or unchanged signaling bit field, and a detection location of a second-level DCI, the first-level DCI being located in a first control region, the second-level DCI being located in a second control region.

7. The method of claim 6, wherein the first stage of DCI is located in a first short TTI of a set of short TTIs, and wherein the second stage of DCI determines from the first stage of DCI that the second stage is located in one or more short TTIs of the set of short TTIs.

8. The method of any of claims 2 to 7, wherein the control region occupies short TTI resources by at least one of:

the control region occupies partial resources of X OFDM symbols, wherein the position of occupying the partial resources of the OFDM symbols is determined by a pre-configuration or a configuration signaling issued by a base station, and the configuration signaling comprises: short control format indication CFI information in a high-level signaling system message block SIB or physical layer signaling;

the control region and a short Physical Downlink Shared Channel (PDSCH) are subjected to frequency division multiplexing, and partial PRB resources of the short physical resource block are occupied; the position of occupying part of short PRB resources is determined by a pre-configuration mode or a configuration signaling sent by a base station, and the configuration signaling comprises at least one of the following: the cell public signaling SIB and UE special signaling radio resource control RRC.

9. The method of claim 8, wherein the control region occupies a portion of resources of X OFDM symbols, comprising:

10. The method of claim 8, wherein the short CFI information is carried by a short Physical Control Format Indicator Channel (PCFICH) channel, and wherein the short PCFICH channel occupies the resource location by: in the first OFDM symbol in all or the first short TTI in a group of short TTIs, a transmission is punctured and a fixed position control channel element CCE or resource element set REG or resource block RE is used.

11. The method of claim 8, wherein the amount of the following resources occupied by the control region is a fixed value or is configured by a base station through a specific signaling: XPRB, short PRB, RBG, wherein, appointed signalling includes: SIB, RRC, short CFI.

12. The method of claim 1, wherein the short CCEs used by the short PDCCH include: when the short CCE consists of short REGs, selecting short REGs with the same interval to form the short CCE, or the short CCE occupies one or more short PRBs.

13. The method of claim 12, wherein the REs occupied by the short REG pairs are numbered from 0 to i in a sequence from frequency domain first to time domain second or from time domain first to frequency domain second, and a resource block with the same number is selected as a short REG, wherein the REs occupied by the short REG pairs are the rest of the REs except the REs occupied by the pilot in the short PRB or XPRB.

14. The method of claim 1, wherein when the downlink control channel is in the first control region, the determination of the number of candidate sets for each short TTI at least comprises one of:

the number of candidate sets in one or more short TTIs in a group of short TTIs is greater than the number of candidate sets in the remaining short TTIs.

15. The method of claim 1, wherein when the downlink control channel is in the second control region, a detection position of a short PDCCH is determined in a short TTI according to a UE ID or a C-RNTI, wherein the detection position is determined at least by one of:

16. The method of claim 1, wherein short TTIs of different terminals occupy different short PRBs or different OFDM symbols.

17. The method of claim 1, wherein the aggregation level corresponding to the downlink control channel comprises: a fixed one or more aggregation levels, one or more aggregation levels configured by a base station, wherein the aggregation level is selected from the set L = {1, 2, 4, 8, 16, 24, 32}.

18. The method of claim 1,

when the downlink control channel is multiplexed and scrambled in a short TTI, the initial value of the scrambling sequence is determined at least through the sequence number of the short TTI, wherein the sequence number of the short TTI at least comprises one of the following: sequence number in 1ms sub-frame, sequence number in radio frame.

19. A method for determining a downlink control channel includes:

20. A device for determining a downlink control channel, applied to a terminal, includes:

21. A device for determining a downlink control channel is applied to a base station, and is characterized by comprising:

22. A terminal, comprising: the apparatus of claim 20.

23. A base station, comprising: the apparatus of claim 21.