CN102271016B - A kind of collocation method of novel TDD HARQ UL Un subframe - Google Patents

Abstract

The present invention discloses a novel TDD HARQ UL Un subframe configuration method. The method includes the following steps: Step 1: Select a DL subframe at the eNB side according to the minimum feedback delay principle, and place the selected DL subframe Configure it as a UL Un subframe; step 2, at the RN end, configure the DL subframe corresponding to the selected DL subframe as a UL Un subframe, which is used to replace the UL subframe to complete Un communication. In the present invention, the DL subframe is designed as a new type of UL Un subframe to replace the traditional TDD HARQ UL subframe, thereby solving the problem of lack of UL subframes in the Un interface in the LTE-A system, and avoiding the need to modify the original LTE user protocol at the Uu interface. The modification made the original LTE users get good compatibility in the LTE-A relay system.

Description

A new TDD HARQ UL Un subframe configuration method

technical field

The invention belongs to the technical field of mobile communication, and relates to a configuration method of a novel TDD HARQ UL Un subframe.

Background technique

The mobile communication technology with the greatest development potential and the broadest market prospect in today's communication field has ushered in the 3G era. However, in order to solve the problems of insufficient spectrum resources, limited system capacity, and increasing user (User Equipment, UE) demand, the International Telecommunication Union (ITU) launched a technical solicitation for the fourth-generation mobile communication system IMT-Advanced in February 2008. Work. In response to the ITU-R IMT-Advanced technical solicitation, 3GPP, which once formulated the most influential 3G UMTS technical standard in the industry, was unwilling to be lonely, and launched the Long Term Evolution-Advanced (LTE) in March 2008. LTE-A) standard process.

A feature of the LTE-A system is the introduction of a relay station (Relay Station, RS) into the system. The introduction of RS improves the coverage of the signal and the capacity of the system to a certain extent. However, due to the introduction of the relay station, the time division duplex (Time Division Duplex, TDD) system Hybrid Automatic Repeat-reQuest (HARQ) timing and the allocation of Un interface subframes will be affected. In 3GPP WG1 RAN 60 times Two principles for subframe allocation of the Un interface of the TDD system were adopted at the meeting:

(1) For the TDD system, it supports both symmetric and asymmetric DL/UL Un subframe allocation methods;

(2) For the TDD system, it supports the explicit allocation of Un UL subframes.

However, how to determine the allocation of TDD Un interface subframes and backhaul HARQ timing is still a problem that needs to be explored. For example, if the UL (Up Link) subframe is used on the Un interface to feed back ACK/NACK signaling for a group of related DL (Down Link) subframes, according to the original LTE protocol and the particularity of the Un interface, this group Some subframes in the DL subframe will be allocated to the Uu interface (the interface between the relay and the users under the jurisdiction of the relay station), so that the ACK/NACK feedback signaling of the DL subframe allocated to the Uu interface will have no corresponding UL subframe for feedback. In order to solve this problem, some companies propose to modify the HARQ timing of the original LTE protocol, and use the UL subframe allocated to the Uu interface to feed back, so as to solve this problem. However, modifying the original LTE protocol will make the original LTE users incompatible with the system, so this should be avoided in the LTE-A standardization work.

Taking TDD HARQ configuration 2 as an example, as shown in Figure 1, since the four subframes 0, 1, 5, and 6 need to transmit some special signaling, they cannot be applied to the Un interface, so they can only be used on the Uu interface. However, there are only two UL subframes 2, 7 in this configuration. It can be seen from Figure 1 that UL subframe 2 feeds back ACK/NACK signaling of DL subframes 4, 5, 6, and 8, and is scheduled by DL subframe 8; UL subframe 7 feeds back DL subframes 9, 0, 1, 3 ACK/NACK signaling, and is scheduled by DL subframe 3. In order to maintain the original LTE protocol on the Uu interface, UL subframe 2 and UL subframe 7 must be applied to the Uu interface, so that there will be no UL subframe available on the Un interface. If UL subframe 2 or 7 is applied to the Un interface, then DL subframes 0, 1, 5, and 6 will lack the UL subframes for feedback of their signaling. If the original LTE protocol is modified to replace subframe 7 with subframe 2 Feedback ACK/NACK signaling of DL subframes 5 and 6, or make subframe 7 replace subframe 2 to feed back ACK/NACK signaling of DL subframes 0 and 1, which will lead to modification of the original LTE protocol on the Uu interface, This makes the original LTE users unable to be compatible with the existing system, so the existing technology cannot solve the above-mentioned problem of missing UL subframes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a novel TDD HARQ UL Un subframe configuration method, which can solve the problem of missing UL subframes without changing the original LTE protocol at the Uu interface.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A configuration method of a novel TDD HARQ UL Un subframe comprises the following steps:

Step 1: Select a DL subframe at the eNB side according to the minimum feedback delay principle, and configure the selected DL subframe as a UL Un subframe;

Step 2, at the RN end, configure the DL subframe corresponding to the selected DL subframe as a UL Un subframe, which is used to replace the UL subframe to complete Un communication.

As a preferred solution of the present invention, in step 1, the reconfiguration method of the selected DL subframe at the eNB side is: the first n OFDM symbols of the selected DL subframe are used to transmit the physical downlink link control channel, and inform the macro user that the selected DL subframe is an MBSFN subframe; the n+1th OFDM symbol of the selected DL subframe is used for conversion from downlink transmission to uplink reception, from The n+2th OFDM symbol starts to receive uplink data from the RN.

As another preferred solution of the present invention, in step 2, the configuration method of the corresponding DL subframe at the RN end is: the first n+1 OFDM symbols of the corresponding DL subframe are used to transmit the physical downlink Link control channel, and inform the user under the jurisdiction of the RN that the corresponding DL subframe is an MBSFN subframe; the corresponding DL subframe sends the ACK/ NACK feeds back signaling and scheduled UL data information to the eNB.

As another preferred solution of the present invention, the ratio of the number of DL subframes configured as UL Un subframes to the number of ULUn subframes is 1:1, 2:1 or 3:1.

The beneficial effects of the present invention are: the present invention designs the DL subframe as a new type of UL Un subframe to replace the traditional TDD HARQ UL subframe, thereby solving the problem of missing UL subframes on the Un interface in the LTE-A system, and avoiding The Uu interface modifies the original LTE user protocol, so that the original LTE users are well compatible in the LTE-A relay system.

Description of drawings

Figure 1 is a TDD HARQ LTE configuration diagram;

Figure 2 is a schematic diagram of UL Un subframe configuration;

FIG. 3 is a schematic diagram of DL subframe 3 configured as a UL Un subframe in Embodiment 2;

FIG. 4 is a schematic diagram of configuring DL subframe 3 as a UL Un subframe in Embodiment 3;

FIG. 5 is a schematic diagram of configuring DL subframe 3 as a UL Un subframe in Embodiment 4.

Detailed ways

In LTE-A system Un interface TDD HARQ subframe configuration, due to the introduction of RN, it is necessary to allocate uplink and downlink subframes to the Un interface. However, due to the particularity of the TDD frame structure, when designing the HARQ timing, in some configurations, each UL subframe needs to carry ACK/NACK feedback signaling of multiple DL subframes. If the DL subframe associated with the feedback signaling is allocated to the Uu interface, and the UL subframe that should carry the ACK/NACK feedback signaling of multiple DL subframes is allocated to the Un interface, this will cause the DL subframe The ACK/NACK feedback signaling of the DL subframe is lost, that is, the Un interface cannot receive the ACK/NACK feedback signaling of the DL subframe. In order to ensure that the ACK/NACK feedback signaling of the DL subframe is fed back, more UL subframes are needed. However, in actual subframe allocation, UL subframe resources that can be allocated to the Un interface are often scarce. In order to solve this problem, the present invention designs the DL subframe as a new type of UL Un subframe to replace the traditional TDD HARQ UL subframe, thereby solving the problem that the Un interface in the LTE-A system lacks the UL subframe, and avoids the original LTE The revision of the user protocol enables the original LTE users to be well compatible in the LTE-A relay system.

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Embodiment one

This embodiment provides a new TDD HARQ UL Un subframe configuration method, taking TDD HARQ configuration 2 shown in FIG. 1 as an example. In Figure 1, subframes 0, 1, 5, and 6 need to transmit some special signaling, so they can only be used on the Uu interface. However, there are only two UL subframes 2 and 7 in this configuration. It can be seen from Figure 1 that UL subframe 2 feeds back ACK/NACK signaling of DL subframes 4, 5, 6, and 8 in the original LTE protocol, and is scheduled by DL subframe 8; UL subframe 7 feeds back in the original LTE protocol ACK/NACK signaling of DL subframes 9, 0, 1, and 3, and is scheduled by DL subframe 3. If UL subframe 2 and 7 are applied to Uu interface, then Un interface will have no UL subframe available; if UL subframe 2 or 7 is applied to Un interface, then DL subframe 0, 1 or 5, 6 will lack feedback UL subframe for its ACK/NACK signaling. Therefore, in the present invention, the DL subframe is configured as a new UL Un subframe to replace the UL subframe to complete Un communication.

Next, consider selecting an appropriate DL subframe to be configured as a new UL Un subframe. Excluding DL subframes 0, 1, 5, and 6, there are still four DL subframes of subframes 3, 4, 8, and 9. It can be seen from Table 1 that the transmission delay after each subframe is configured as a ULUn subframe. Taking subframe 3 as an example, when subframe 3 is selected as the UL Un subframe, the feedback/scheduling delay of subframe 4 is 9ms, the feedback/scheduling delay of subframe 8 is 5ms, and the feedback/scheduling delay of subframe 9 The delay is 4ms.

Table 1: Feedback/scheduling delay table after each subframe is configured as UL Un subframe

It can be seen from Table 1 that the feedback/scheduling delay of subframes 3 and 8 is small, and subframe 3 or 8 can be selected as the new UL Un subframe according to the DL subframe allocation of the Un interface.

According to the principle of minimum feedback delay, taking subframe 3 as an example, the process of configuring a new UL Un subframe is shown in Figure 2.

1. Select DL subframe 3 on the eNB side and configure it as a new UL Un subframe:

First, the first n OFDM symbols are used to transmit the physical downlink control channel (PDCCH), and inform the macro user (macro UE) that it is a multicast single frequency network subframe (MBSFN);

Secondly, the n+1th OFDM symbol is used for conversion from downlink transmission to uplink reception, then the uplink data from the RN starts to be received from the n+2th OFDM symbol.

2. Configure the corresponding subframe 3 as a UL Un subframe at the RN side:

First, the first n+1 OFDM symbols are used to transmit the PDCCH, and inform the users under the jurisdiction of the RN that this subframe is an MBSFN subframe;

Secondly, the n+2th OFDM symbol starts to send the ACK/NACK feedback signaling of each DL subframe at the Un interface and the scheduled UL data information to the eNB.

In the present invention, the DL subframe is designed as a new type of UL Un subframe to replace the traditional TDD HARQ UL subframe, thereby solving the problem of missing UL subframes in the Un interface in the LTE-A system, and avoiding the modification of the original LTE user protocol. So that the original LTE users can get good compatibility in the LTE-A relay system.

Embodiment two

In this embodiment, the DL subframe 3 is configured as a new UL Un subframe according to the configuration method described in Embodiment 1. The schematic diagram of the new UL Un subframe is shown in FIG. 3 , where DL:UL=1:1.

Embodiment three

The difference between this embodiment and the second embodiment is: DL:UL=2:1.

Embodiment Four

The difference between this embodiment and the second embodiment is: DL:UL=3:1.

The method described in the present invention can be applied to other configurations of TDD HARQ, and different ratios related to TDD subframe DL:UL configuration, and can also be applied to other systems that need to use UL subframe configuration.

The description and application of the invention herein is illustrative and is not intended to limit the scope of the invention to the above-described embodiments. Variations and changes to the embodiments disclosed herein are possible, and substitutions and equivalents for various components of the embodiments are known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be realized in other forms, structures, arrangements, proportions, and with other elements, materials and components without departing from the spirit or essential characteristics of the present invention.

Claims (4)

1. A method for configuring a novel TDD HARQ UL Un subframe, characterized in that the method comprises the following steps: Step 1: Select a DL subframe at the eNB side according to the minimum feedback delay principle, and configure the selected DL subframe as a UL Un subframe; Step 2, at the RN end, configure the DL subframe corresponding to the selected DL subframe as a UL Un subframe, which is used to replace the UL subframe to complete Un communication. 2. The method for configuring the new TDD HARQ UL Un subframe according to claim 1, wherein in step 1, the method for reconfiguring the selected DL subframe at the eNB side is: The first n OFDM symbols of the selected DL subframe are used to transmit a physical downlink control channel, and inform the macro user that the selected DL subframe is an MBSFN subframe; The n+1th OFDM symbol of the selected DL subframe is used for switching from downlink transmission to uplink reception, and the uplink data from the RN is received from the n+2th OFDM symbol. 3. The configuration method of the novel TDD HARQ UL Un subframe according to claim 1, characterized in that, in step 2, the configuration method of the corresponding DL subframe at the RN end is: The first n+1 OFDM symbols of the corresponding DL subframe are used to transmit a physical downlink control channel, and inform the user under the jurisdiction of the RN that the corresponding DL subframe is an MBSFN subframe; The corresponding DL subframe sends the ACK/NACK feedback signaling of each DL subframe at the Un interface side and the scheduled UL data information to the eNB side from the n+2th OFDM symbol. 4. According to the configuration method of the novel TDD HARQ UL Un subframe according to any one of claims 1 to 3, it is characterized in that: the number of DL subframes configured as UL Un subframes is equal to the number of UL Un subframes The ratio is 1:1, 2:1 or 3:1.