JP7733628B2 - Method for communication between a terminal, a repeater and a base station - Google Patents

Description

This invention relates to repeater technology deployed in a Radio Access Network (RAN). In particular, it relates to a Network Control Repeater (NCR) used in the 5G standard.

Figure 1 is a system configuration diagram of a RAN including a repeater.

The mobile communication system is composed of a mobile terminal 3 , a plurality of base stations 2 , and a core system 4 .
1, a repeater 1 is interposed in a RAN that is configured between a base station 2 and a terminal 3. The repeater 1 amplifies and relays radio signals, thereby expanding the coverage (radio wave range) between the base station 2 and the terminal 3.

The terminal 3 is called "UE (User Equipment)" and communicates with the core system 4 via the base station 2. At this time, the terminal 3 generally communicates radio signals with the base station 2 without being aware of the presence of the repeater 1. Of course, the terminal 3 does not exchange control information with the repeater 1.

Base station 2 is referred to as a "gNB" and communicates with multiple terminals 3 directly or via repeater 1. Note that base station 2 may exist as a separate physical location, or may be logically divided within the RAN using, for example, virtualization or slicing technology.

The core system 4 is composed of control plane equipment and user plane equipment.
The control plane facility devices are a group of network devices that transmit and receive control signals for establishing communication and the like, and include a group of network devices such as an Access and Mobility Management Function (AMF) and a Session Management Function (SMF).
The user plane facility equipment includes a group of UPF (User Plane Function) devices for transmitting and receiving user data.

Figure 2 is an explanatory diagram showing the direct communication method between a terminal and a base station.

FIG. 2( a ) shows a direct communication method between a terminal 3 and a base station 2 .
Link (base station - terminal): 28GHz band, 400MHz width, spatial multiplexing 1
The terminal 3 configures one physical packet with one component carrier and transmits the one component carrier to the base station 2 .

FIG. 2B shows a direct communication method using a frequency multiplexing section method between the terminal 3 and the base station 2.
Link (base station - terminal): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
Access link (repeater terminal): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
Backhaul link (base station - repeater): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1

Here, Repeater 1 is an RF (Radio Frequency) repeater that simply amplifies and forwards wireless signals. Because Repeater 1 has a physical layer amplification function, the communication method for the backhaul link and access link is the same. Of course, Base Station 2 and Terminal 3 do not need to be aware of the presence of Repeater 1 at all.

For the uplink, terminal 3 transmits physical packets using frequency multiplexing carrier aggregation (see, for example, non-patent document 7). Terminal 3 configures one physical packet with one component carrier and transmits four component carriers simultaneously using carrier aggregation. Base station 2 receives four physical packets simultaneously.

Figure 3 shows the protocol configuration between a base station and a terminal via a repeater.

The repeater 1 of the NCR based on the 5G RAN standard has a control plane function and accepts control from the base station (see, for example, non-patent document 3).
3, the repeater 1 has a control plane function 11 and a user plane function 12. The control plane function 11 is NCR-MT (Mobile Termination), and the user plane function 12 is NCR-Fwd (Forwarding).

<Control Plane Function 11>
The control plane function 11 establishes a control link with the base station 2. According to Fig. 3, the control plane function 11 has the following protocol configuration.
RRC (Radio Resource Control)
PDCP (Packet Domain Convergence Protocol)
RLC (Radio Link Control)
MAC (Media Access Control)
Physical Layer

<User Plane Function 12>
The user plane function 12 establishes a backhaul link with the base station 2 and an access link with the terminal 3. According to Fig. 3, the following protocol configuration is provided.
SDAP (Service Data Adaptation Protocol)
PDCP (Packet Domain Convergence Protocol)
RLC (Radio Link Control)
MAC (Media Access Control)
Physical Layer

When the control plane function 11 receives a paging message from the base station 2, it transitions to a connected state and establishes a control link with the base station 2. The control plane function 11 then transitions the forwarding unit of the user plane function 12 to an on state. The repeater 1 then begins amplifying and forwarding the radio signal to relay it between the base station 2 and the terminal 3.

3GPP, TS 36.211, “Evolved Universal Terrestrial Radio Access (E UTRA );Physical channels and modulation”, v17.2.0 3GPP, TS 36.213, “Evolved Universal Terrestrial Radio Access (E UTRA );Physical layer procedures”, v17.2.0 3GPP, TR 38.867, “Study on NR network controlled repeaters”, v0.1.0 3GPP, TS 38.213, “Physical layer procedures for control”, v17.2.0 3GPP, TS 38.331, “Radio Resource Control (RRC) protocol specification”, v17.1.0 3GPP, TS 38.211, “Physical channels and modulation”, v17.2.0, 6.3.1.3 Layer mapping, Table 7.3.1.3 1: Codeword to layer mapping for spatial multiplexing "5G/NR - Carrier Aggregation", [online], [Retrieved September 15, 2022], Internet <URL: https://www.sharetechnote.com/html/5G/5G_CarrrierAggregation.html> "5G/NR - MIMO UL", [online], [searched September 15, 2022], Internet <URL: https://www.sharetechnote.com/html/5G/5G_MIMO_UL.html>

Figure 4 is an explanatory diagram showing a RAN using conventional technology with a multi-axis conversion repeater.

According to the multiple axis conversion method shown in Figure 4, repeater 1 applies frequency multiplexing carrier aggregation to the access link and spatial multiplexing MIMO (Multi-Input Multi-Output) to the backhaul link (see, for example, Non-Patent Document 8).

According to FIG. 4, when viewed from the repeater 1, the communication method of the access link and the communication method of the backhaul link are different.
Access link (repeater terminal): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
Backhaul link (base station - repeater): 28GHz band, 400MHz width, spatial multiplexing 4

When relaying, repeater 1 converts between signals on the frequency axis and signals on the spatial axis. By relaying using the multi-axis conversion method, repeater 1 can achieve high-capacity, low-latency communication from terminal 3 to base station 2.

For the access link, the terminal 3 transmits a physical packet to the repeater 1 by frequency multiplexing carrier aggregation. The terminal 3 configures one physical packet with one component carrier and transmits four component carriers simultaneously by carrier aggregation.
The repeater 1 simultaneously receives four component carriers from the terminal 3 via carrier aggregation for the access link.

For the backhaul link, repeater 1 transmits component carriers to base station 2 using spatial multiplexing MIMO. Typically, in MIMO, one physical packet (here, a component carrier) is composed of, for example, four layer blocks. Repeater 1 amplifies each of the four component carriers received simultaneously, and then simultaneously transmits them to base station 2 in four layer blocks.

Here, base station 2 simultaneously receives four component carriers in four layer blocks. At this time, a problem arises in that base station 2 attempts to demodulate one physical packet from the four simultaneously received layer blocks due to MIMO reception processing, but fails. To be precise, four physical packets must be demodulated from the four simultaneously received layer blocks.

In response to this, terminal 3 can also transmit in advance with a physical packet configuration that corresponds to the presence of repeater 1. However, terminal 3 is not aware of the presence of repeater 1 in the RAN. Furthermore, repeater 1 cannot send a control signal to terminal 3 to notify it of the relay method. In other words, terminal 3 cannot control the communication method depending on the presence of repeater 1 in the RAN.

The present invention therefore aims to provide a base station, terminal, program, system, and communication method that allows a terminal to control the communication method depending on the presence of a repeater in the RAN.

According to the communication method of the present invention,
a first step in which a terminal configures one physical packet with one component carrier and frequency-multiplexes and transmits the packet in an uplink using a first communication scheme;
a second step of transmitting control information instructing the terminal to use the second communication method via the repeater in a downlink from the base station;
a third step in which, after receiving the control information, the terminal divides one physical packet into a plurality of child physical packets, configures each child physical packet with one component carrier, and frequency-multiplexes the plurality of component carriers and transmits the child physical packets in uplink as a second communication method;
a fourth step in which, when the repeater simultaneously receives a plurality of frequency-multiplexed component carriers from the terminal, the repeater configures each component carrier into a layer block, spatially multiplexes the plurality of layer blocks, and transmits the layer blocks to the base station in the uplink;
The present invention is characterized by having the following.

According to another embodiment of the communication method of the present invention,
In the second step, the base station establishes a control link with the repeater, and after establishing a random access channel with the terminal via the repeater, transmits control information instructing the second communication method in the downlink.
It is also preferable.

The base station, terminal, program, system, and communication method of the present invention allow the terminal to control the communication method depending on the presence of a repeater in the RAN.

FIG. 1 is a system configuration diagram of a RAN including a repeater. FIG. 1 is an explanatory diagram illustrating a direct communication method between a terminal and a base station. FIG. 10 is a diagram illustrating a protocol configuration between a base station and a terminal via a repeater. FIG. 1 is an explanatory diagram showing a conventional RAN using a multiple axis conversion repeater. FIG. 1 is an explanatory diagram showing a RAN in the present invention in which a repeater of a multiple axis conversion method is interposed. FIG. 10 is a sequence diagram of a RAN in the present invention with a repeater interposed therebetween.

The following describes in detail an embodiment of the present invention using the drawings.

According to the present invention, communication is performed between the base station and the terminal directly or by relaying via a repeater.
Here, it is assumed that the terminal can apply the following two communication methods depending on whether or not a repeater of the multiple axis conversion method is interposed.
"First communication method": No intervention of a repeater using a multiple axis conversion method "Second communication method": Intervention of a repeater using a multiple axis conversion method In other words, when a "direct communication method" in which a repeater relays by simply amplifying and forwarding a wireless signal is applied, the terminal applies the "first communication method." On the other hand, when a repeater applies the "multiple axis conversion method" between an access link and a backhaul link, the terminal applies the "second communication method."

According to the present invention, the terminal applies a first communication method in which the radio signal is simply amplified and transferred in exactly the same manner as in FIG. 2(b) described above.
Link (base station - terminal): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
Access link (repeater terminal): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
Backhaul link (base station - repeater): 39 GHz band, 1.6 GHz width (4CC), spatial multiplexing 1
According to the above-mentioned FIG. 2( b ), frequency multiplexed carrier aggregation is applied to the uplink from terminal 3 .
In the first communication method, one physical packet is composed of one component carrier, and then, for example, four component carriers are transmitted simultaneously by carrier aggregation.
The base station 2 receives four component carriers simultaneously, regardless of whether the repeater 1 is present or not.

Figure 5 is an explanatory diagram showing the RAN of the present invention, which incorporates a multi-axis conversion repeater.

According to the present invention, the terminal applies the second communication method as shown in FIG.
Access link (Repeater 1 - Terminal 3): 39GHz band, 1.6GHz width, 4CC
Backhaul link (base station 2 - repeater 1): 28GHz band, 400MHz width, spatial multiplexing 4

In FIG. 5 as well, frequency multiplexed carrier aggregation is applied to the uplink from terminal 3 .
In the second communication method, one physical packet is divided into, for example, four child physical packets, and each child physical packet is configured with one component carrier.The four component carriers are then transmitted simultaneously by carrier aggregation.
Repeater 1 will receive four component carriers simultaneously.

Also, according to FIG. 5, MIMO spatial multiplexing is applied to the uplink from repeater 1.
The repeater 1 simultaneously receives four component carriers (four child physical packets) for the access link using frequency multiplexing carrier aggregation. In contrast, the MIMO using spatial multiplexing configures each component carrier received from the terminal 3 as a layer block. That is, the repeater 1 multiplexes and transmits the four layer blocks from multiple antenna elements.
By using MIMO, base station 2 can simultaneously receive four layer blocks from repeater 1 and demodulate them into one physical packet.

5, it should be noted that, in the second communication method, the terminal 3 transmits, for example, four child physical packets to the repeater 1 using four component carriers (= one physical packet), and the repeater 1 transfers the four component carriers in four layer blocks to the base station 2. In other words, the repeater 1 only amplifies in component carrier units (= child physical packets).
In response to this, the base station 2 simultaneously receives four component carriers in four layer blocks, and can demodulate one physical packet from the four simultaneously received layer blocks.

Figure 6 is a sequence diagram of the RAN in the present invention with a repeater interposed.

According to FIG. 6, it is assumed that the terminal 3 is capable of applying the first communication method and the second communication method, as in the above-described FIG.
(S1) First, the base station 2 establishes a control link with the repeater 1 over the backhaul link.
(S2) Next, the base station 2 establishes a random access channel with the terminal 3 via the repeater 1.
(S3) Next, the base station 2 establishes an RRC (Radio Resource Control) connection with the terminal 3 via the repeater 1.
At this time, the terminal 3 attempts to apply the default "first communication method" for frequency multiplexing carrier aggregation. According to the first communication method, the terminal 3 configures one physical packet with one component carrier and transmits, for example, four component carriers simultaneously.

(S4) Assume that base station 2 applies spatial multiplexing MIMO transmission to uplink via a control link with repeater 1. At this time, base station 2 includes "control information (second communication method)" in RRC Reconfiguration and transmits it to terminal 3 via repeater 1 so that terminal 3 applies the "second communication method."

(S5) Terminal 3 applies the second communication method to frequency multiplexing carrier aggregation. According to the second communication method, terminal 3 divides one physical packet into, for example, four child physical packets. Each child physical packet is then configured with one component carrier. In other words, one physical packet is divided into, for example, four component carriers, and the four component carriers are transmitted simultaneously using carrier aggregation.

As described above in detail, according to the base station, terminal, program, system and communication method of the present invention, the terminal can control the communication method depending on the presence of a repeater in the RAN.
Specifically, even if the access link uses a frequency multiplexing method and the backhaul link uses a repeater that uses a multiple axis conversion method such as a spatial multiplexing method, the repeater only amplifies on a component carrier basis, and base station 2 will not fail to reconstruct a single physical packet.

Furthermore, this will enable, for example, "high-capacity, low-latency communications to be achieved for the RAN between base stations and terminals by using repeaters as an intermediary," which will contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization and foster innovation."

With regard to the various embodiments of the present invention described above, those skilled in the art will be able to easily make various changes, modifications, and omissions that fall within the scope of the technical spirit and principles of the present invention. The foregoing description is merely illustrative and is not intended to be limiting in any way. The present invention is limited only by the claims and their equivalents.

1 Repeater 11 Control plane function 12 User plane function 2 Base station 3 Terminal 4 Core system

Claims (2)

a first step in which a terminal configures one physical packet with one component carrier and frequency-multiplexes and transmits the packet in an uplink using a first communication scheme;
a second step of transmitting control information instructing the terminal to use the second communication method via the repeater in a downlink from the base station;
a third step in which, after receiving the control information, the terminal divides one physical packet into a plurality of child physical packets, configures each child physical packet with one component carrier, and frequency-multiplexes the plurality of component carriers and transmits the child physical packets in uplink as a second communication method;
a fourth step in which, when the repeater simultaneously receives a plurality of frequency-multiplexed component carriers from the terminal, the repeater configures each component carrier into a layer block, spatially multiplexes the plurality of layer blocks, and transmits the layer blocks to the base station in the uplink;
A communication method comprising: In the second step, the base station establishes a control link with the repeater, and after establishing a random access channel with the terminal via the repeater, transmits control information instructing the second communication method in the downlink.
2. The communication method according to claim 1.