WO-2026094192-A1 - WIRELESS COMMUNICATION SYSTEM AND WIRELESS COMMUNICATION METHOD

WO2026094192A1WO 2026094192 A1WO2026094192 A1WO 2026094192A1WO-2026094192-A1

Abstract

This wireless communication system has a Point-to-MultiPoint (P2MP) configuration. The wireless communication system includes: an RoF slave unit for transmitting a pseudo random number sequence code predetermined for the own unit to an RoF master unit when receiving an uplink signal; and an RoF master unit control unit for executing autocorrelation acquisition processing for taking autocorrelation of the pseudo random number sequence code that has passed through a multiplexer/demultiplexer included in the RoF master unit.

Inventors

TAKAHASHI YUUTA
FUJITA TAKAFUMI
SUGA MIZUKI
TSUBOI HIDEYUKI
YORIOKA Hiroto
YAMAMOTO YASUYOSHI

Assignees

ＮＴＴ株式会社

Dates

Publication Date: 20260507
Application Date: 20241031

Claims (4)

A wireless communication system with a P2MP (Point-to-MultiPoint) configuration, A RoF slave unit transmits a predetermined pseudo-random number sequence code to the RoF master unit at the timing of receiving the uplink signal, The RoF master control unit performs an autocorrelation acquisition process to obtain the autocorrelation of the pseudo-random number sequence code that has passed through the multiplexer/demultiplexer provided in the RoF master unit, A wireless communication system equipped with [the necessary components].
The aforementioned pseudo-random number sequence code is the same for RoF slave devices that are predetermined to belong to the same group according to a set of rules. The wireless communication system according to claim 1.
The RoF master control unit changes the connection relationship between the RoF slave unit and the RoF master unit when predetermined conditions are met. The wireless communication system according to claim 1.
A wireless communication method performed by a wireless communication system in a P2MP (Point-to-MultiPoint) configuration, comprising: an RoF slave unit that transmits a predetermined pseudo-random number sequence code to an RoF master unit at the timing of receiving an uplink signal; and an RoF master unit control unit that performs an autocorrelation acquisition process to obtain the autocorrelation of the pseudo-random number sequence code that has passed through a multiplexer/demultiplexer provided by the RoF master unit; The RoF slave unit transmits a predetermined pseudo-random number sequence code to the RoF master unit at the aforementioned timing in a transmission step, The RoF master control unit performs the autocorrelation acquisition step, which involves the autocorrelation acquisition process, A wireless communication method having

Description

Wireless communication systems and wireless communication methods This invention relates to a wireless communication system and a wireless communication method. Analog-RoF (A-RoF), which transmits analog signals over optical cables, is being studied to achieve flexible and economical wireless area deployment by dividing wireless base station functions into aggregation stations and extension stations, and by deploying simple extension stations. A Single Frequency Network (SFN) using a Point-to-Multi-Point (P2MP) architecture, where multiple antennas (i.e., multiple Radio Over Fiber (RoF) devices) extend from a single Radio Frequency (RF) point, is a necessary network topology for expanding wireless coverage areas, particularly in areas where high-frequency wireless propagation is difficult due to high propagation loss and high directivity. As a D-RoF (Digital-RoF) system, a standardized device for replicating data has been established by installing a Fronthaul Multiplexer (FHM) in the fronthaul section between the O-DU and O-RU in an Open RAN (see Non-Patent Document 1). P2MP needs to eliminate the ingress noise effect, which is added in proportion to the number of RoF slaves (i.e., the number of extended antennas), especially in uplink (UL) communication (for example, when there are 2 RoF slaves, the noise increases by 3 dB compared to when there is 1 RoF slave). One method for removing ingress noise in A-RoF is to use resource mapping information to turn on the path receiving the uplink signal at the appropriate time, and turn off other paths. This method requires knowing which RoF slave unit the communicating UE (User Equipment) is located on. An explanatory diagram illustrating a wireless communication system according to an embodiment.A flowchart illustrating an example of the processing flow performed by the wireless communication system in the embodiment.A diagram showing an example of the configuration of an RoF slave unit and a RoF master unit in an embodiment.A diagram showing a more specific example of the hardware configuration of the RoF slave unit in the embodiment.A diagram showing a more specific example of the hardware configuration of the RoF master unit in the embodiment. (Embodiment) Figure 1 is an explanatory diagram illustrating an embodiment of the wireless communication system 100. The wireless communication system 100 is a P2MP (Point-to-MultiPoint) wireless communication system. Therefore, the wireless communication system 100 comprises at least a Radio Over Fiber (RoF) slave unit, an RoF master unit equipped with a multiplexer/demultiplexer, and a aggregation station. The connection between the RoF master unit and the RoF slave unit may be analog RoF, digital RoF, or coaxial cable. The wireless communication system 100 will be explained more specifically using the example in Figure 1. The wireless communication system 100 comprises multiple RoF slave units 1. In Figure 1, RoF slave unit 1-n to RoF slave unit 1-(n+k) are examples of RoF slave units 1. Note that n is an integer greater than or equal to 1, and k is an integer greater than or equal to 1. Each RoF slave unit 1 is equipped with an overhanging antenna 10. In the example in Figure 1, RoF slave unit 1-n receives the uplink signal transmitted by UE (User Equipment) 9-m (hereinafter referred to as the "uplink signal") and the uplink signal transmitted by UE (User Equipment) 9-(m+1). In the example in Figure 1, RoF slave unit 1-(n+k) receives the uplink signal transmitted by UE (User Equipment) 9-(m+1) and the uplink signal transmitted by UE (User Equipment) 9-(m+l). Note that l is an integer greater than or equal to 1. The RoF slave unit 1 transmits a predetermined pseudo-random number sequence code to the RoF master unit 2 at the timing of receiving the uplink signal. The wireless communication system 100 includes a RoF master unit 2. The RoF master unit 2 includes a signal combiner/demultiplexer 20. In the example shown in Figure 1, the signal combiner/demultiplexer 20 is connected to at least RoF slave units 1-n and 1-(n+k). Therefore, the signal combiner/demultiplexer 20 receives at least the signal transmitted by RoF slave unit 1-n and the signal transmitted by RoF slave unit 1-(n+k). That is, the signal combiner/demultiplexer 20 receives at least the pseudo-random number sequence code transmitted by RoF slave unit 1-n and the pseudo-random number sequence code transmitted by RoF slave unit 1-(n+k). The RoF master unit 2 performs autocorrelation acquisition processing. This autocorrelation acquisition processing involves obtaining the autocorrelation of the PN (Pseudo Random Noise) code that has passed through the multiplexer/demultiplexer 20. The autocorrelation of the pseudo-random number sequence code reveals information indicating the RoF slave unit 1 that transmitted the pseudo-random number sequence code (hereinafter referred to as "source identification information") and information indicating the timing at which