Method and equipment for controlling downlink control channel transmission of short TTI (transmission time interval)
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and a device for transmitting a short TTI (transmission Time Interval) downlink control channel in a conventional control region.
Background
The mobile internet is subverting the traditional mobile communication business mode, providing unprecedented use experience for users, and profoundly influencing the aspects of work and life of people. The mobile internet can promote further upgrading of human social information interaction modes, and provide richer business experiences such as augmented reality, virtual reality, ultra-high definition (3D) video and mobile cloud for users. The further development of the mobile internet will bring the mobile traffic to thousands of times increase in the future, and promote a new revolution of mobile communication technology and industry. The internet of things expands the service range of mobile communication, and extends from person-to-person communication to intelligent interconnection of people and objects, so that the mobile communication technology permeates into wider industries and fields. In the future, mobile medical treatment, internet of vehicles, smart home, industrial control, environmental monitoring and the like will promote the explosive growth of internet of things application, and hundreds of millions of devices will access the network to realize real 'everything interconnection'. Meanwhile, a large amount of equipment connection and diversified internet of things services can bring new technical challenges to mobile communication.
With the continuous emergence and enrichment of new service demands, higher performance demands are put on future mobile communication systems, such as higher peak rate, better user experience rate, smaller delay, higher reliability, higher spectrum efficiency and higher energy consumption efficiency, and the like, and more users need to be supported to access and use various service types. In order to support various terminal connections with huge number and different service types, flexible configuration of uplink and downlink resources becomes a great trend of technical development. Future system resources can be divided into different sub-bands according to different services, and TTI with different lengths is divided on the sub-bands to meet various service requirements.
The conventional LTE (Long Term Evolution ) FDD (Frequency Division duplex) system uses a frame structure (FS 1 for short) whose structure is shown in fig. 1. In an FDD system, uplink and downlink transmissions use different carrier frequencies, and both uplink and downlink transmissions use the same frame structure. On each carrier, a 10ms (millisecond) long radio frame consists of 10 1ms subframes, each of which is divided into two 0.5ms slots. The TTI duration for uplink and downlink data transmission is 1 ms.
The existing LTE TDD (time division duplex) system uses a frame structure (FS 2) as shown in fig. 2. In a TDD system, uplink and downlink transmissions use different subframes or different time slots on the same frequency. Each 10ms radio frame in FS2 consists of two 5ms fields, each field containing 5 subframes of 1ms length. Subframes in FS2 are divided into three categories: the subframe comprises a Downlink subframe, an Uplink subframe and special subframes, wherein each special subframe comprises three parts of a Downlink transmission Time Slot (DwPTS, Downlink Pilot Time Slot), a Guard interval (GP, Guard Period) and an Uplink transmission Time Slot (UpPTS, Uplink Pilot Time Slot). The DwPTS can transmit downlink pilot frequency, downlink service data and downlink control signaling; the GP does not transmit any signal; the UpPTS transmits only a random access and Sounding Reference Signal (SRS), and cannot transmit uplink traffic or uplink control information. Each half frame comprises at least 1 downlink subframe, at least 1 uplink subframe and at most 1 special subframe. Table 1 shows 7 uplink and downlink subframe configurations supported in FS 2.
Table 1: uplink-downlink configurations
Existing LTE downlink resource granularity
In the existing LTE, the minimum resource granularity is one OFDM (orthogonal frequency division multiplexing) symbol in the time domain, and one subcarrier in the frequency domain. As shown in fig. 3, (k, l) is a number of a basic resource element re (resource element). WhereinPRBs (physical resource elements) are resource elements of a larger dimension, consisting ofAnd RE. One subframe has one PRB pair, which is a basic unit for data resource allocation.
Existing LTE downlink control channel
A PDCCH (physical downlink control channel) of the LTE system is used for carrying scheduling information and other control information. A plurality of PDCCHs can be arranged in a control region of each downlink subframe, the size of the control region is determined by a PCFICH (physical control format indicator channel), and the control region occupies 1-4 OFDM symbols. The transmission of one control channel occupies one CCE (control channel element) or a plurality of consecutive CCEs, each CCE is composed of 9 REGs (resource element groups), and REGs included in the CCEs of PDCCH are REGs that are not used for carrying PCFICH and PHICH (physical hybrid automatic repeat indicator channel).
In order to expand the capacity of the PDCCH, an EPDCCH (enhanced physical downlink control channel) is introduced in Rel-11. The EPDCCH is transmitted in a data region in a subframe and cannot occupy a transmission space of the PDCCH. Similar to PDCCH, the concept of EREG (enhanced resource element group) and ECCE (enhanced control channel element) is introduced.
In existing LTE systems, the TTI length is fixed to 1 ms. Each TTI of the LTE system needs to include a control region, which occupies the first few OFDM symbols of the TTI or a set of pre-configured PRB pair. For short TTIs, it is desirable to minimize the resource overhead of the control region for short TTIs. If the condition allows, for example, the legacy control region has enough resources, if the control channel of the short TTI in the subframe is in the legacy control region, the resource overhead of the short TTI control channel can be reduced.
However, in the existing standard of the LTE system, there is no explicit scheme for determining whether the short TTI is transmitted in the legacy control region (legacy control region).
Disclosure of Invention
In view of the foregoing technical problems, embodiments of the present invention provide a method and an apparatus for controlling transmission of a downlink control channel of a short TTI, so as to solve the technical problem of determining transmission positions of downlink control channels of one or more short TTIs.
In a first aspect of the embodiments of the present invention, a method for controlling downlink control channel transmission of a short TTI is provided, including:
the base station determines the transmission positions of one or more downlink control channels of short TTI, wherein the transmission positions are as follows: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
Optionally, the method further comprises:
and the base station informs the terminal of the transmission positions of the downlink control channels of the one or more short TTIs through a high-level signaling.
Optionally, after determining the transmission positions of the downlink control channels of the one or more short TTIs, the base station does not explicitly signal the terminal of the transmission positions of the downlink control channels of the one or more short TTIs.
Optionally, the determining, by the base station, the transmission position of the downlink control channel of one or more short TTIs includes:
the base station determines that the downlink control channel of the short TTI is demodulated based on CRS or demodulated based on DMRS according to a transmission mode configured to the terminal;
determining that the downlink control channels of one or more short TTIs cannot be transmitted in a legacy control region of the LTE system if the downlink control channels of the short TTIs are demodulated based on the DMRS;
and if the downlink control channel of the short TTI is demodulated based on the CRS, the base station places zero or one or more downlink control channels of the short TTI in a traditional control region of the LTE system according to the requirement for transmission.
Optionally, the plurality of short TTIs are in the same subframe.
Optionally, when the control channels of the multiple short TTIs are transmitted in a legacy control region of an LTE system, the DCI carried on the control channel of each short TTI needs to include location information of the short TTI;
when the control channel of the short TTI is transmitted in the conventional control region of the LTE system and the position of the short TTI in the LTE subframe is determined, the position information of the short TTI does not need to be contained in the DCI carried on the control channel of the short TTI.
Optionally, the size of the DCI format of the corresponding short TTI transmitted in the legacy control region of the LTE system is different from the format size of the legacy DCI; or the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system reuses the size of the legacy DCI format, and the specific bit field indicates that the DCI is the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system, or the DCI is distinguished as the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system by the RNTI.
Optionally, the method further comprises:
when the downlink control channel of the short TTI is transmitted in a traditional control area of an LTE system, the base station allocates resources for the downlink control channel in the USS of a terminal, and the terminal is a terminal scheduled by control information on the downlink control channel.
Optionally, the downlink control channel is transmitted based on CRS.
Optionally, the method further comprises:
and when the downlink control channel of the short TTI is not transmitted in the traditional control region of the LTE system, the base station allocates resources for the downlink control channel in the control region of the short TTI.
Optionally, the downlink control channel is based on CRS and/or DMRS transmission.
According to a second aspect of the embodiments of the present invention, there is provided a method for controlling downlink control channel transmission of a short TTI, including:
the terminal determines the transmission positions of one or more downlink control channels of short TTI, wherein the transmission positions are as follows: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
Optionally, the determining, by the terminal, the transmission position of the downlink control channel of one or more short TTIs includes:
the terminal receives configuration information;
and the terminal determines the transmission positions of the downlink control channels of one or more short TTIs according to the configuration information.
Optionally, the method further comprises:
if the downlink control channel of the short TTI is determined to be transmitted in a conventional control region of the LTE system, the terminal detects the downlink control channel in the USS of the terminal in the conventional control region;
and if the downlink control channel of the short TTI is determined to be transmitted in the control region of the short TTI, the terminal detects the downlink control channel in the control region of the short TTI.
Optionally, the determining, by the terminal, the transmission position of the downlink control channel of one or more short TTIs includes:
and the terminal determines the transmission positions of the downlink control channels of one or more short TTIs through blind detection.
Optionally, the blind detection is:
the terminal attempts to detect the control channel for the short TTI within the USS of the terminal in the legacy control region of the LTE system.
Optionally, the method further comprises:
if the terminal detects the downlink control channel of the short TTI in the USS of the terminal in the traditional control region of the LTE system, the terminal completes data transmission in the short TTI according to the downlink control information carried by the downlink control channel, and the downlink control channel is not detected in the short TTI;
and if the terminal does not detect the downlink control channel of the short TTI in the USS of the terminal in the traditional control region of the LTE system, the terminal detects the downlink control channel related to the terminal in the control region of the short TTI.
Optionally, the determining, by the terminal, the transmission position of the downlink control channel of one or more short TTIs includes:
the terminal determines that the downlink control channel of the short TTI is demodulated based on CRS or based on DMRS according to the transmission mode of the terminal;
if the downlink control channel of the short TTI is demodulated based on the DMRS, the terminal cannot detect the downlink control channel of the short TTI in a traditional control region of an LTE system;
and if the downlink control channel of the short TTI is demodulated based on the CRS, the terminal detects the downlink control channel of the short TTI in a traditional control region of an LTE system.
Optionally, the plurality of short TTIs are in the same subframe.
Optionally, if the downlink control channel is transmitted in a legacy control region of an LTE system, the method further includes:
and the terminal demodulates the downlink control channel based on the CRS.
Optionally, if the downlink control channel is transmitted in a legacy control region of an LTE system, the method further includes:
the terminal distinguishes the traditional DCI of the LTE system and the DCI applicable to the short TTI according to different DCI format sizes, or determines that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to a specific indication domain in the DCI, or determines that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to the RNTI.
Optionally, if the downlink control channel is transmitted in the control region of the short TTI, the method further includes:
and the terminal demodulates the downlink control channel based on the CRS and/or the DMRS.
According to a third aspect of the embodiments of the present invention, there is also provided a base station, including:
a first determining module, configured to determine a transmission location of a downlink control channel of one or more short TTIs, where the transmission location is: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
Optionally, the base station further includes:
and the first notification module is used for notifying the terminal of the transmission positions of the downlink control channels of the one or more short TTIs through a high-level signaling.
Optionally, the base station further includes:
and the second notification module is used for determining the transmission positions of the downlink control channels of one or more short TTIs and not notifying the terminal of the transmission positions of the downlink control channels of the one or more short TTIs through explicit signaling.
Optionally, the determining module is further configured to:
determining that the downlink control channel of the short TTI is demodulated based on CRS or based on DMRS according to a transmission mode configured to a terminal;
determining that the downlink control channels of one or more short TTIs cannot be transmitted in a legacy control region of the LTE system if the downlink control channels of the short TTIs are demodulated based on the DMRS;
and if the downlink control channel of the short TTI is demodulated based on the CRS, placing zero or one or more downlink control channels of the short TTI in a traditional control region of the LTE system for transmission according to the requirement.
Optionally, the plurality of short TTIs are in the same subframe.
Optionally, when the control channels of the multiple short TTIs are transmitted in a legacy control region of an LTE system, the DCI carried on the control channel of each short TTI needs to include location information of the short TTI;
when the control channel of the short TTI is transmitted in the conventional control region of the LTE system and the position of the short TTI in the LTE subframe is determined, the position information of the short TTI does not need to be contained in the DCI carried on the control channel of the short TTI.
Optionally, the size of the DCI format of the corresponding short TTI transmitted in the legacy control region of the LTE system is different from the format size of the legacy DCI; or the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system reuses the size of the legacy DCI format, and a specific bit field is used to indicate whether the DCI is the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system, or the DCI is distinguished as the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system by the RNTI.
Optionally, the base station further includes:
the first resource allocation module is used for allocating resources for a downlink control channel of a short TTI in a conventional control region of an LTE system when the downlink control channel is transmitted, wherein the terminal is a terminal scheduled by control information on the downlink control channel.
Optionally, the downlink control channel is transmitted based on CRS.
Optionally, the base station further includes:
and the second resource allocation module is used for allocating resources for the downlink control channel in the control region of the short TTI when the downlink control channel of the short TTI is not transmitted in the traditional control region of the LTE system.
Optionally, the downlink control channel is based on CRS and/or DMRS transmission.
According to a fourth aspect of the embodiments of the present invention, there is also provided a terminal, including:
a second determining module, configured to determine a transmission position of a downlink control channel of one or more short TTIs, where the transmission position is: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
Optionally, the second determining module is further configured to: receiving configuration information; and determining the transmission positions of the downlink control channels of one or more short TTIs according to the configuration information.
Optionally, the terminal further includes:
a first detection module, configured to detect a downlink control channel of the short TTI in a USS of the terminal in a legacy control region if it is determined that the downlink control channel is transmitted in the legacy control region of the LTE system;
and if the downlink control channel of the short TTI is determined to be transmitted in the control region of the short TTI, detecting the downlink control channel in the control region of the short TTI.
Optionally, the second determining module is further configured to: and determining the transmission positions of the downlink control channels of one or more short TTIs by blind detection.
Optionally, the second determining module is further configured to: attempting to detect the control channel for the short TTI within the USS of the terminal in the legacy control region of the LTE system.
Optionally, the terminal further includes:
a second detection module, configured to complete data transmission in the short TTI according to downlink control information carried by the downlink control channel if the terminal detects the downlink control channel of the short TTI in the USS of the terminal in a legacy control area of the LTE system, and no longer detect the downlink control channel in the short TTI;
and if the terminal does not detect the downlink control channel of the short TTI in the USS of the terminal in the traditional control region of the LTE system, detecting the downlink control channel related to the terminal in the control region of the short TTI.
Optionally, the second determining module is further configured to: determining the demodulation of the downlink control channel of the short TTI based on the CRS or the DMRS according to the transmission mode of the terminal;
if the downlink control channel of the short TTI is demodulated based on the DMRS, the terminal cannot detect the downlink control channel of the short TTI in a traditional control region of an LTE system;
and if the downlink control channel of the short TTI is demodulated based on the CRS, the terminal detects the downlink control channel of the short TTI in a traditional control region of an LTE system.
Optionally, the plurality of short TTIs are in the same subframe.
Optionally, the terminal further includes:
a first demodulation module, configured to demodulate the downlink control channel based on a CRS if the downlink control channel is transmitted in a legacy control region of an LTE system.
Optionally, the terminal further includes:
and the distinguishing module is used for distinguishing the traditional DCI of the LTE system and the DCI applicable to the short TTI according to different DCI format sizes, or determining that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to a specific indication domain in the DCI, or determining that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to the RNTI.
Optionally, the terminal further includes:
and the first demodulation module is used for demodulating the downlink control channel based on the CRS and/or the DMRS if the downlink control channel is transmitted in the control region of the short TTI.
One of the above technical solutions has the following advantages or beneficial effects: the base station can determine whether the downlink control channel of one or more short TTIs is transmitted in the traditional control region of the LTE system or the control region of the short TTI, then the base station informs (explicitly or implicitly) the terminal of the transmission position of the downlink control channel of the short TTI, and the terminal detects the downlink control channel at the transmission position of the corresponding control channel, or the terminal can also blindly detect whether the downlink control channel of one or more short TTIs is transmitted in the traditional control region of the LTE system or the control region of the short TTI.
Drawings
Fig. 1 is a schematic diagram of a frame structure used in a conventional LTE FDD system;
fig. 2 is a diagram illustrating a frame structure used by a conventional LTE TDD system;
fig. 3 is a schematic diagram of a conventional downlink resource grid;
fig. 4 is a flowchart of a method for controlling downlink control channel transmission of a short TTI according to a first embodiment of the present invention;
fig. 5 is a flowchart of a method for controlling downlink control channel transmission of a short TTI according to a second embodiment of the present invention;
fig. 6 is a block diagram of a base station according to a third embodiment of the present invention;
fig. 7 is a block diagram of a terminal according to a fourth embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are explicitly shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
As will be appreciated by one skilled in the art, embodiments of the present invention may be embodied as a system, apparatus, device, method, or computer program product. Thus, embodiments of the invention may be embodied in the form of: entirely hardware, entirely software (including firmware, resident software, micro-code, etc.), or a combination of hardware and software.
In the embodiment of the invention, the related equipment comprises a base station and a terminal, and downlink transmission and uplink reception can be carried out between the base station and the terminal accessed to the base station.
The base station may include only Radio frequency (e.g., Remote Radio Unit (RRU)), or include both baseband and Radio frequency (e.g., Active antenna). A base station may include only a Baseband (e.g., a Baseband Unit (BBU)); or the antenna does not include any digital/radio frequency function of an air interface layer at all, is only responsible for high-level signal processing, and puts baseband processing of the air interface layer into the intelligent antenna. Other various network implementation possibilities also exist.
A Terminal may also be referred to as User Equipment (UE), or may be referred to as Terminal, Mobile Station (MS), Mobile Terminal (RAN), and the like, and the Terminal may communicate with one or more core networks via a Radio Access Network (RAN), for example, the Terminal may be a Mobile phone (or may be referred to as a "cellular" phone), a computer with a Mobile Terminal, and the like, and for example, the Terminal may also be a portable, pocket, handheld, computer-embedded, or vehicle-mounted Mobile device, and they exchange voice and/or data with the RAN. The terminal in the embodiment of the present invention may also be a Device to Device (D2D) terminal or a Machine to Machine (M2M) terminal.
Example one
Referring to fig. 4, a method for controlling downlink control channel transmission of a short TTI is shown, which includes the following steps:
step 401, the base station determines the transmission positions of the downlink control channels of one or more short TTIs, where the transmission positions are: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
In this embodiment, optionally, multiple short TTIs are in the same subframe, and it should be noted that a specific position of the multiple short TTIs is not limited in this embodiment.
The length of the short TTI is less than 1 ms.
The legacy control region (legacy control region) of the LTE system is a control region for transmitting a PDCCH (physical downlink control channel) in the LTE system.
The control region of the short TTI is a region for transmitting a control channel of the short TTI.
In this embodiment, after the base station determines the transmission positions of the downlink control channels of one or more short TTIs, the base station may notify the terminal in an explicit notification or an implicit notification manner.
The first alternative is as follows:
and the base station informs the terminal of the transmission position of the downlink control channel of one or more short TTIs through a high-level signaling.
For example, the higher layer signaling includes indication information, and when the indication information is "1", the indication information indicates that the downlink control channel of the short TTI is transmitted in the legacy control region of the LTE system.
The second option is:
the base station determines the transmission positions of the downlink control channels of one or more short TTIs and does not inform the terminal of the transmission positions of the downlink control channels of the one or more short TTIs by explicit signaling.
For example, the base station autonomously selects (e.g., according to scheduling resources or requirements) to transmit the downlink control channel in one or more short TTIs in the legacy control region of the LTE system or in the control region of the short TTI, and the base station does not inform the terminal of the transmission position of the downlink control channel of the short TTI by explicit signaling.
The above-mentioned method not notified by explicit signaling may be, compared to the method notified by explicit signaling, the method notified by explicit signaling may be: the notification is explicitly made by higher layer signaling, although it is not limited thereto.
In the second alternative, the base station may determine, according to the transmission mode configured for the terminal, that the downlink control channel of the short TTI is demodulated based on a CRS (cell-specific pilot) or based on a DMRS (demodulation reference signal); if the downlink control channel of the short TTI is demodulated based on the DMRS, the base station determines that the downlink control channel of one or more short TTIs can not be transmitted in the traditional control region of the LTE system, namely the base station places the downlink control channel of one or more short TTIs in the control region of the short TTI for transmission; if the downlink control channel of the short TTI is demodulated based on the CRS, the base station places zero or one or more downlink control channels of the short TTI in a traditional control region of the LTE system according to the requirement for transmission.
In this embodiment, optionally, when the control channels of multiple short TTIs are transmitted in the legacy control region of the LTE system, DCI (downlink control information) carried on the control channel of each short TTI needs to include location information of the short TTI;
when a control channel of a short TTI is transmitted in a legacy control region of an LTE system and the position of the short TTI in an LTE subframe is determined, it is not necessary for DCI carried on the control channel of the short TTI to include the position information of the short TTI. For example, the position of the short TTI in the LTE subframe is fixed to the nth short TTI in the subframe, where N is a positive integer greater than or equal to 1 and less than the number of short TTIs included in the frame.
In this embodiment, optionally, the base station may implicitly indicate whether the downlink control channel of each short TTI is transmitted in the legacy control region of the LTE system through DCI carried on the control channel of the short TTI.
For example: the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system is different from the format size of the legacy DCI; or the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system reuses the size of the legacy DCI format, and indicates that the DCI is the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system using a specific bit field, or distinguishes the DCI as the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system using an RNTI (radio network temporary identity).
In this embodiment, optionally, after the step 401, the method may further include:
and the base station transmits the downlink control channel of the short TTI according to the determined transmission position of the downlink control channel of the short TTI.
In this embodiment, optionally, when the downlink control channel of the short TTI is transmitted in the legacy control region of the LTE system, the method further includes:
a base station allocates resources for a downlink control channel in a USS (user equipment private search space) of a terminal, and the terminal is a terminal scheduled by control information on the downlink control channel; further, optionally, the downlink control channel is transmitted based on the CRS.
In this embodiment, optionally, when the downlink control channel of the short TTI is not transmitted in the legacy control region of the LTE system, the method further includes:
and the base station allocates resources for the downlink control channel in the control region of the short TTI. Further, optionally, the downlink control channel is based on CRS and/or DMRS transmission.
In this embodiment, the base station can determine whether the downlink control channel of one or more short TTIs is transmitted in the conventional control region of the LTE system or the control region of the short TTI, and then the base station notifies (explicitly or implicitly) the terminal of the transmission position of the downlink control channel of the short TTI, and the terminal detects the downlink control channel at the transmission position of the corresponding control channel.
Example two
Referring to fig. 5, a method for controlling downlink control channel transmission of a short TTI is shown, which includes the following steps:
step 501, the terminal determines the transmission positions of the downlink control channels of one or more short TTIs, where the transmission positions are: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
In this embodiment, optionally, multiple short TTIs are in the same subframe, and it should be noted that, in this embodiment, specific positions of the multiple short TTIs are not limited, for example, the multiple short TTIs may also be in different subframes.
The legacy control region (legacy control region) of the LTE system is a control region for transmitting a PDCCH (physical downlink control channel) in the LTE system.
The control region of the short TTI is a region for transmitting a control channel of the short TTI.
In this embodiment, optionally, the terminal may determine the transmission position of the downlink control channel of one or more short TTIs in the following manner.
Alternatively, the terminal may determine the transmission position of the downlink control channel of one or more short TTIs through the configuration information.
Specifically, the terminal receives configuration information; and the terminal determines the transmission positions of the downlink control channels of one or more short TTIs according to the configuration information.
If the downlink control channel of the short TTI is determined to be transmitted in the traditional control area of the LTE system, the terminal detects the downlink control channel in the USS of the terminal in the traditional control area;
and if the downlink control channel of the short TTI is determined to be transmitted in the control region of the short TTI, the terminal detects the downlink control channel in the control region of the short TTI.
And in an optional mode II, the terminal determines the transmission positions of the downlink control channels of one or more short TTIs through blind detection.
One way of the above-mentioned blind test may be: the terminal attempts to detect the control channel for the short TTI within the USS of the terminal in the legacy control region of the LTE system.
If the terminal detects the downlink control channel of the TTI in the USS of the terminal in the traditional control region of the LTE system, the terminal completes data transmission in the short TTI according to the downlink control information carried by the downlink control channel, and the downlink control channel is not detected in the short TTI;
if the terminal does not detect the downlink control channel of the short TTI in the USS of the terminal in the traditional control region of the LTE system, the terminal detects the downlink control channel related to the terminal in the control region of the short TTI.
The Downlink Control Information (DCI) may carry location information of the short TTI, and when the terminal receives the downlink control information, the DCI includes short TTI indication information indicating which short TTI in the subframe the short TTI control channel corresponds to.
In this embodiment, the manner for the terminal to implicitly determine the transmission position of the downlink control channel of one or more short TTIs may also be:
the terminal determines that the downlink control channel of the short TTI is demodulated based on the CRS or demodulated based on the DMRS according to the transmission mode of the terminal;
if the downlink control channel of the short TTI is demodulated based on the DMRS, the terminal cannot detect the downlink control channel of the short TTI in the traditional control region of the LTE system, and only detects the downlink control channel of the short TTI in the control region of the short TTI;
and if the downlink control channel of the short TTI is demodulated based on the CRS, the terminal detects the downlink control channel of the short TTI in the traditional control region of the LTE system.
In this embodiment, optionally, if the downlink control channel is transmitted in a legacy control region of the LTE system, the method further includes: and the terminal demodulates the downlink control channel based on the CRS.
In this embodiment, optionally, if the downlink control channel is transmitted in a legacy control region of the LTE system, the method further includes:
the terminal distinguishes the traditional DCI of the LTE system and the DCI applicable to the short TTI according to different DCI format sizes, or determines that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to a specific indication domain in the DCI, or determines that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to the RNTI.
In this embodiment, optionally, if the downlink control channel is transmitted in the control region of the short TTI, the method further includes: and the terminal demodulates the downlink control channel based on the CRS and/or the DMRS.
In this embodiment, the terminal determines the transmission position of the downlink control channel of the short TTI, and then the terminal may detect the downlink control channel at the transmission position of the corresponding control channel, or the terminal may also blindly detect whether the downlink control channel of one or more short TTIs is transmitted in the conventional control region of the LTE system or in the control region of the short TTI.
The transmission position of the downlink control channel of one or more short TTIs can be controlled, so that the overhead of the downlink control channel of the short TTI in the subframe is reduced, and the resource utilization rate is improved.
EXAMPLE III
The base station informs the terminal through 1bit high-level signaling whether the downlink control channel of the first short TTI in a subframe is transmitted in legacy control region in LTE system. For example, the higher layer signaling includes indication information, and when the indication information is 1, the legacy control region of the LTE system transmits the downlink control channel indicating the short TTI. Assuming that the UE1 (first terminal) needs to transmit data in the short TTI, its downlink control information is DCI1 (first downlink control information). Since the higher layer signaling informs the terminal that the downlink control channel of the first short TTI in the subframe needs to be transmitted in the legacy control region in the LTE system, the UE1 needs to blindly detect the DCI1 in its USS. The format of DCI1 is different in size from the currently defined DCI format in the LTE system (the currently defined DCI format may also be referred to as a legacy DCI format), and UE1 may distinguish legacy DCI format from DCI format for a short TTI by blind detection; or, the DCI size of the short TTI is the same as that of the legacy DCI, and the received DCI is determined to be used for the short TTI or the legacy TTI according to the specific indication bit in the DCI of the short TTI; or, the control channel of the short TTI is scrambled by using a specific RNTI, and the terminal can distinguish whether the received channel is a legacy control channel or a control channel of the short TTI by blind detection. The UE1 transmits data in the short TTI according to the DCI1 if its DCI1 is received in legacy control region of the LTE system.
And when the indication information is 0, indicating that the downlink control channel of the short TTI is transmitted in the control region of the short TTI. For example, if the UE1 knows that the downlink control channel of the short TTI is transmitted in the control region of the short TTI after receiving the higher layer signaling, the UE1 will only detect its own downlink control channel in the control region of the short TTI.
The control channel of the short TTI transmitted in the legacy control region of the LTE system may be a control channel of another short TTI in the subframe.
Example four
The terminal determines whether the control channel of the first short TTI in the subframe is transmitted in a legacy control region of the LTE system in a blind detection mode. For example, UE1 (first terminal) needs to transmit data in the first short TTI in the subframe, and its downlink control information is DCI 1. The UE1 needs to detect the downlink control channel of the short TTI in its own USS in legacy control region of the LTE system, and attempt to receive the DCI1 (first DCI) transmitted on the downlink control channel. The DCI1 size is different from the DCI size of the scheduling normal TTI (normal TTI) data, UE1 may distinguish different DCI formats; or, the DCI size of the short TTI is the same as that of legacy DCI (legacy DCI), and the received DCI is determined to be used for the short TTI or legacy TTI according to a specific indication bit in the DCI of the short TTI; or, the control channel of the short TTI is scrambled by using a specific RNTI, and the terminal can distinguish whether the received channel is a legacy control channel or a control channel of the short TTI by blind detection. When the UE1 receives the DCI1, data is transmitted in the short TTI according to the scheduling information of the DCI1, and the downlink control channel is not detected in the downlink control region of the short TTI. If the UE1 does not receive the downlink control information of the short TTI in its own USS in the legacy control region, it is necessary to continue detecting the downlink control channel of the short TTI in the downlink control region of the short TTI.
The control channel of the short TTI transmitted in the legacy control region of the LTE system may be a control channel of another short TTI in the subframe.
EXAMPLE five
Assuming that the UL grant (uplink grant) of UE1 (first terminal) needs to be transmitted in the first short TTI in the subframe, and that UE1 has received a higher layer signaling, a legacy control region transmission in LTE systems. The UE1 detects the downlink control channel for the short TTI within its own USS in the legacy control region and attempts to accept the UL grant. The DCI carrying the downlink control information of the short TTI is different from the legacy DCI in size, and the terminal can distinguish the DCI carrying the downlink control information of the short TTI through blind detection; or the DCI size of the short TTI is the same as that of the legacy DCI, and the received DCI is determined to be used for the short TTI or the legacy TTI according to the specific indication bit in the DCI of the short TTI; or, the control channel of the short TTI is scrambled by using a specific RNTI, and the terminal can distinguish whether the received channel is a legacy control channel or a control channel of the short TTI by blind detection. If the UE1 receives the UL grant, the UL grant is not received in the control region of the short TTI.
The control channel of the short TTI transmitted in the legacy control region of the LTE system may be a control channel of another short TTI in the subframe.
Example six:
assume that a subframe contains 7 short TTIs. The base station informs the terminal through a 3bit (bit) high-level signaling whether a downlink control channel of a certain short TTI in the subframe is transmitted in a legacy control region in the LTE system. For example, the higher layer signaling includes indication information, and when the indication information is 011, the downlink control channel indicating the 3 rd short TTI in the subframe is transmitted in legacy control region of the LTE system, which can be specifically seen in table 1.
Assuming that the UE1 (first terminal) needs to transmit data in the short TTI, its downlink control information is DCI1 (first DCI). Since the higher layer signaling informs the downlink control channel of the 3 rd short TTI in the terminal subframe that legacy control region transmission in the LTE system is required, the UE1 needs to blindly detect the DCI1 in its USS. The size of the DCI1 is different from the currently defined DCI size in the LTE system, and the UE can distinguish legacy dciformate from DCI format for a short TTI by blind detection; or the DCI size of the short TTI is the same as that of the legacy DCI, and the received DCI is determined to be used for the short TTI or the legacy TTI according to the specific indication bit in the DCI of the short TTI; or, the control channel of the short TTI is scrambled by using a specific RNTI, and the terminal can distinguish whether the received channel is a legacy control channel or a control channel of the short TTI by blind detection. The UE1 transmits data in the short TTI according to the DCI1 if its DCI1 is received in legacy control region of the LTE system.
And when the indication information is 000, indicating that the downlink control channel of the short TTI is transmitted in the control region of the short TTI. For example, if the UE1 knows that the downlink control channel of the short TTI is transmitted in the control region of the short TTI after receiving the higher layer signaling, the UE1 will only detect its own downlink control channel in the control region of the short TTI.
Based on this embodiment, the higher layer signaling may also indicate that the control channels of multiple short TTIs are transmitted in legacy control region of the LTE system.
Or, the base station only informs the terminal whether to transmit the downlink control channel of the short TTI in the legacy control region of the LTE system through 1-bit high-level signaling. And the downlink control information of each short TTI transmitted in the legacy control region in a subframe of the LTE system carries the position information of the short TTI.
Table 1: high-layer indication information transmitted by control channel of short TTI in legacy control region
EXAMPLE seven
The terminal determines whether a control channel of a certain short TTI in the subframe is transmitted in a legacy control region of the LTE system in a blind detection mode. Assume that a subframe contains 7 short TTIs. For example, UE1 (first terminal) needs to transmit data in the 3 rd short TTI in the subframe, and its downlink control information is DCI1 (first DCI). The UE1 needs to detect the downlink control channel of the short TTI in its own USS in legacy control region of the LTE system, and attempt to receive the DCI1 transmitted on the downlink control channel. The size of the DCI1 is different from that of the DCI for scheduling normal TTI data, and the UE can distinguish different DCI sizes; or the DCI size of the short TTI is the same as that of the legacy DCI, and the received DCI is determined to be used for the short TTI or the legacy TTI according to the specific indication bit in the DCI of the short TTI; or, the control channel of the short TTI is scrambled by using a specific RNTI, and the terminal can distinguish whether the received channel is a legacy control channel or a control channel of the short TTI by blind detection. When the UE1 receives the DCI1, the DCI1 includes short TTI indication information indicating which short TTI in the subframe the short TTI control channel corresponds to, for example, the indication information is 011, which indicates that the control channel of the short TTI corresponds to the 4 th short TTI in the subframe. See table 2 for specific indication information. And then the terminal transmits data in the short TTI according to the scheduling information of the DCI1, and does not continue to detect the downlink control channel in the downlink control region of the short TTI. If the UE1 does not receive the downlink control information of the short TTI in its own USS in the legacy control region, it is necessary to continue detecting the downlink control channel of the short TTI in the downlink control region of the short TTI.
Table 2: indication information transmitted in legacy control region in control information of short TTI
Example eight:
with reference to the third to seventh embodiments, this embodiment provides an optional implementation manner, where when the downlink control channel of the short TTI is demodulated based on the DMRS, the downlink control channel of the short TTI cannot be transmitted in legacy control region of the LTE system. The base station may configure the downlink control channel of the short TTI not to be transmitted in the legacy control region of the LTE system through high-level signaling. Or the terminal implicitly determines that the downlink control channel of the short TTI is demodulated based on the CRS or based on the DMRS according to the transmission mode of the terminal. And if the downlink control channel of the short TTI is demodulated based on the DMRS, the terminal does not try to receive the downlink control channel of the short TTI in a legacy control region of the LTE system. And if the downlink control channel of the short TTI is demodulated based on the CRS, the terminal tries to receive the downlink control channel of the short TTI in a legacy control region of the LTE system.
Example nine
The present embodiment is based on the third embodiment and the sixth embodiment, and provides an alternative implementation manner. Based on the third embodiment and the sixth embodiment, when the higher layer signaling indicates that the control channel of one or more short TTIs of the terminal is transmitted in the legacy control region, but the terminal does not detect the control channel of the relevant short TTI in the legacy control region, the terminal continues to detect and receive the downlink control channel in the control region of the corresponding short TTI.
Example ten
Referring to fig. 6, a base station is shown, the base station 600 comprising:
a first determining module 601, configured to determine transmission positions of downlink control channels of one or more short TTIs, where the transmission positions are: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
In this embodiment, optionally, the base station further includes:
a first notifying module, configured to notify the terminal of the transmission positions of the downlink control channels of the one or more short TTIs through a high-level signaling.
In this embodiment, optionally, the base station further includes:
and the second notification module is used for determining the transmission positions of the downlink control channels of one or more short TTIs and not notifying the terminal of the transmission positions of the downlink control channels of the one or more short TTIs through explicit signaling.
In this embodiment, optionally, the determining module is further configured to:
determining that the downlink control channel of the short TTI is demodulated based on CRS or based on DMRS according to a transmission mode configured to a terminal;
determining that the downlink control channels of one or more short TTIs cannot be transmitted in a legacy control region of the LTE system if the downlink control channels of the short TTIs are demodulated based on the DMRS;
and if the downlink control channel of the short TTI is demodulated based on the CRS, placing zero or one or more downlink control channels of the short TTI in a traditional control region of the LTE system for transmission according to the requirement.
In this embodiment, optionally, the multiple short TTIs are in the same subframe.
In this embodiment, optionally, when the control channels of the multiple short TTIs are transmitted in the legacy control region of the LTE system, the DCI carried on the control channel of each short TTI needs to include the location information of the short TTI;
when the control channel of the short TTI is transmitted in the conventional control region of the LTE system and the position of the short TTI in the LTE subframe is determined, the position information of the short TTI does not need to be contained in the DCI carried on the control channel of the short TTI.
In this embodiment, optionally, the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system is different from the format size of the legacy DCI; or the size of the DCI format corresponding to the short TTI transmitted in the legacy control region of the LTE system reuses the size of the legacy DCI format, and the specific bit field indicates that the DCI is the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system, or the DCI is distinguished as the legacy DCI or the DCI corresponding to the short TTI transmitted in the legacy control region of the LTE system by the RNTI.
In this embodiment, optionally, the base station further includes:
a first resource allocation module, configured to allocate resources to a downlink control channel of the one or more short TTIs in a USS of a terminal when the downlink control channel is transmitted in a legacy control region of an LTE system, where the terminal is a terminal scheduled by control information on the downlink control channel;
in this embodiment, optionally, the downlink control channel is transmitted based on CRS.
In this embodiment, optionally, the base station further includes:
and a second resource allocation module, configured to allocate resources for the downlink control channel in the control region of the short TTI when the downlink control channel of the one or more short TTIs is not transmitted in the legacy control region of the LTE system.
In this embodiment, optionally, the downlink control channel is transmitted based on CRS and/or DMRS.
In this embodiment, the base station can determine whether the downlink control channel of one or more short TTIs is transmitted in the conventional control region of the LTE system or the control region of the short TTI, and then the base station notifies (explicitly or implicitly) the terminal of the transmission position of the downlink control channel of the short TTI, and the terminal detects the downlink control channel at the transmission position of the corresponding control channel.
EXAMPLE eleven
Referring to fig. 7, a terminal is shown, the terminal 700 comprising:
a second determining module 701, configured to determine transmission positions of downlink control channels of one or more short TTIs, where the transmission positions are: the transmission is in a legacy control region of an LTE system, or in a control region of a short TTI.
In this embodiment, optionally, the second determining module is further configured to: receiving configuration information; and determining the transmission positions of the downlink control channels of one or more short TTIs according to the configuration information.
In this embodiment, optionally, the terminal further includes:
a first detection module, configured to detect a downlink control channel of the short TTI in a USS of the terminal in a legacy control region if it is determined that the downlink control channel is transmitted in the legacy control region of the LTE system;
and if the downlink control channel of the short TTI is determined to be transmitted in the control region of the short TTI, detecting the downlink control channel in the control region of the short TTI.
In this embodiment, optionally, the second determining module is further configured to: and determining the transmission positions of the downlink control channels of one or more short TTIs by blind detection.
In this embodiment, optionally, the second determining module is further configured to: attempting to detect the control channel for the short TTI within the USS of the terminal in the legacy control region of the LTE system.
In this embodiment, optionally, the terminal further includes:
a second detection module, configured to complete data transmission in the short TTI according to downlink control information carried by the downlink control channel if the terminal detects the downlink control channel of the short TTI in the USS of the terminal in a legacy control area of the LTE system, and no longer detect the downlink control channel in the short TTI;
and if the terminal does not detect the downlink control channel of the short TTI in the USS of the terminal in the traditional control region of the LTE system, detecting the downlink control channel related to the terminal in the control region of the short TTI.
In this embodiment, optionally, the second determining module is further configured to: determining the demodulation of the downlink control channel of the short TTI based on the CRS or the DMRS according to the transmission mode of the terminal;
if the downlink control channel of the short TTI is demodulated based on the DMRS, the terminal cannot detect the downlink control channel of the short TTI in a traditional control region of an LTE system;
and if the downlink control channel of the short TTI is demodulated based on the CRS, the terminal detects the downlink control channel of the short TTI in a traditional control region of an LTE system.
In this embodiment, optionally, the multiple short TTIs are in the same subframe.
In this embodiment, optionally, the terminal further includes:
a first demodulation module, configured to demodulate the downlink control channel based on a CRS if the downlink control channel is transmitted in a legacy control region of an LTE system.
In this embodiment, optionally, the terminal further includes:
and the distinguishing module is used for distinguishing the traditional DCI of the LTE system and the DCI applicable to the short TTI according to different DCI format sizes, or determining that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to a specific indication domain in the DCI, or determining that the DCI is the traditional DCI of the LTE system and the DCI applicable to the short TTI according to the RNTI.
In this embodiment, optionally, the terminal further includes:
and the first demodulation module is used for demodulating the downlink control channel based on the CRS and/or the DMRS if the downlink control channel is transmitted in the control region of the short TTI.
In this embodiment, the terminal determines the transmission position of the downlink control channel of the short TTI, and then the terminal can detect the downlink control channel at the transmission position of the corresponding control channel.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In various embodiments of the present invention, it should be understood that the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.
In addition, the terms "system" and "network" are often used interchangeably herein.
It should be understood that the term "and/or" herein is merely one type of association relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
In the embodiments provided herein, it should be understood that "B corresponding to a" means that B is associated with a from which B can be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may be determined from a and/or other information.
In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be physically included alone, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network-side device) to perform some steps of the transceiving method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
While the preferred embodiments of the present invention have been described, it should be understood that modifications and embellishments could be made by those skilled in the art without departing from the principles of the present invention, and such modifications and embellishments are also within the scope of the present invention.