KR20200066961A - Central Server Architecture for Cousing Frequency and Method for Accessing Frequency - Google Patents

Abstract

Disclosed is a central server architecture and a frequency access method for shared frequency use. The disclosed method includes the steps of: registering the location, frequency of use, and transmission power of each layer in license database; determining a channel allocation state for each layer; and setting the channel of layer 2 and the channel of layer 3 by receiving the number of nodes and the interference boundary value of each layer. According to the disclosed method, the CBRS framework can be extended in a shared frequency use model to support a high priority URLLC service in addition to mMTC.

Description

Central Server Architecture for Cousing Frequency and Method for Accessing Frequency

The present invention relates to a central server architecture and frequency access method for co-frequency use.

In the case of past mobile communication, 2G and 3G mainly provided voice and some data services, and 4G provided data-oriented services in earnest. A key element of 5G is that mobile networks will evolve to support various communication requirements. will be. According to [ITU-2020], in addition to having a higher data rate in 5G/B5G, mMTC and URLLC were adopted as target core performance items. In this aspect (coverage, latency and reliability), 4G is converged with LTE-based technology, while 5G technology is expected to meet the needs of various markets such as IoT, V2X, and PPDR.

There may be some problems with the carriers supporting mMTC and URLLC to meet 5G requirements. MMTC, such as IoT, has a significantly lower spectral efficiency compared to eMBB because the data rate per device is low and the overhead can be increased due to numerous connections. For example, smart metering periodically transmits for a short period of time and is idle for a considerable amount of time between transmissions. In addition, IoT devices have low capability, so they must have low power due to battery problems, but have technical difficulties to provide wide coverage. Therefore, providing mMTC service in the licensed band is not cost efficient. As a result, carriers must secure frequencies at low prices from the government to provide mMTC services.

Unlike mMTC, which takes a spatiotemporally stable form of traffic, URLLC may have a significantly different form of traffic depending on the type of application. Some services, such as V2X, generate traffic evenly in time, while services such as public welfare and disaster relief (PPDR) occur in areas where traffic is very limited in time and space (local and temporal). This means that the traditional PPDR (PS-LTE) in operation is not spectral efficiency. Nevertheless, considering that the URLLC service, which has the same characteristics as PPDR, must be operated with high priority, the government needs to use frequency resources more flexibly.

Moreover, in the future disaster situation, it aims not only to support real-time video and tele-operation through an unmanned mobile vehicle such as a drone, but also to improve the disaster response capability by acting as a base station in case the base station in the disaster area is paralyzed. [512kbps, 100Mbps, 20Mbps, and 20Mbps are required for high-quality real-time voice and video, haptic, and sensor traffic of URLLC-based drones, respectively. Therefore, considering the use of drones in future disaster scenarios, a bandwidth of hundreds of MHz is required in addition to the 20 MHz calculated in traditional PPDR (PS-LTE).

The previously introduced spectrum sharing can be a solution to trade off the interests between the government and telecommunications operators about mMTC and URLLC in the 5G market. The concept of joint use of frequencies is to allow services of different personalities to be used simultaneously, under the conditions that do not interfere with existing users of the low utilization frequency allocated for public use. The most promising existing frequency co-use models are the LSA targeting 2.2-2.4 GHz in Europe and the CBRS targeting 3.55-3.7 GHz in the United States. Currently, studies on mMTC in LSA and CBRS have been actively conducted for the purpose of simply increasing spectral efficiency, while URLLC services such as PPDR are not considered. These services are not only fatal to interference from other classes, but also require enormous bandwidths of hundreds of MHz when considering future large-scale disaster situations. (major challenge in using shared bands for URLLC)

The present invention proposes a new frequency co-use model that can support a URLLC service having a high priority in addition to mMTC by extending the current CBRS framework.

In order to achieve the above object, the step of registering the location, frequency of use, transmission power of each layer in the license database; Determining a channel allocation state for each layer; receiving a node number of each layer, an interference boundary value, and setting a channel of layer 2 and a channel of layer 3, a frequency access method for joint use of frequencies. Is provided.

According to the present invention, the CBRS framework is extended in the frequency co-use model to support URLLC service having high priority in addition to mMTC.

1 is a diagram showing a system model for frequency joint use of the present invention.
2 is a diagram showing the architecture of a frequency co-use model according to an embodiment of the present invention.
3 shows a SAS framework.
4 shows a channel plan of each node.

When it is said to be "connected" with other parts, this includes not only "directly connected" but also "indirectly connected" with another member in between.

Also, when a part “includes” a certain component, this means that other components may be further provided, not excluding other components, unless otherwise specified.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The frequency co-use model proposed in the present invention is a four-layer model in which a special tier having high priority is added between tier 1 and tier 2 of CBRS. We present the frequency-sharing architecture that accommodates the special tier and the functional and operational guidelines of the spectrum access system (SAS) for highly dynamic spectrum access. Also, DSIC method for full-duplex is proposed for mobility support and latency gain of special tier and applied to special tier. The license example and use case for the proposed frequency co-use model are discussed, and finally, the simulation shows the feasibility of the proposed frequency co-use model in a large-scale disaster scenario.

1 is a diagram showing a system model for frequency joint use of the present invention.

Each layer (Tier) registers the location, frequency of use (pictured to the right), and transmit power to the License Database module. The Sensing system senses the location and frequency usage information of each layer to be changed in real time. Based on this, the Spectrum Access System (SAS) manages and operates the frequencies of each layer.

2 is a diagram showing the architecture of a frequency co-use model according to an embodiment of the present invention.

SAS oversees multiple frequency bands and manages the frequency operation of each access layer. In order to protect from interference signals from other layers, it is periodically sensed, and information sensed by space-time is processed into an OP-Map to provide an opportunistic access strategy. CBRS, a three-tier model, created a new business model by expanding the license form in the two-tier model LSA, making frequency sharing more flexible. In response to this, the proposed frequency co-use model is a four-tier model based on the new license type. The added layer (Tier2 or Layer2) is a layer for emergency communication (PPDR), and the lower layers (Tier3,4 or Layer3,4) are licensed with limited frequency usage to ensure high QoS at any time in Tier2.

3 is a view showing a SAS framework.

1) SAS engine consists of Manager and SAS DB of each layer. The sensed information is processed in the OP-Map and provides inter-space-time interference values to Tier 1. Tier2 Manager receives information such as interference and location of Tier1, 2) frequency use database, 3) and registration information from SAS Database module and performs channel assignment algorithm based on this. The Interference management module manages interference information from other layers and the Spectrum usage monitor module monitors available frequency bands in real time to perform highly dynamic channel assignment. Manger of the next layer receives 4) channel assignment results and 5) registration information (ex. Location, transmit power, and antenna gain). And, likewise, the channel assignment algorithm is performed. 6 and 7 are performed similarly. At this time, in Tier 3 and 4, channel probability is performed using access probability (alpha) information.

8) When Tier2 needs emergency communication, Tier2 Manager sends alert message to Multiple frequency bands manager, and Multiple Frequency bands manager sends available frequency information to lower tier. Based on this, the managers of the lower tier adjust the access probability (alpha) value and reflect it in the channel assignment algorithm.

4 is a diagram showing a channel plan of each node.

로 정의하며, 각 node의 coverage는 r이며 any node에서 타 node의 coverage edge까지의 거리는

로 정의한다. 이 밖의 symbolic definition은 아래 표 1에 정리한다.The distance between the i-th node and the j-th node

Defined as, the coverage of each node is r and the distance from any node to the coverage edge of another node is

Is defined as Other symbolic definitions are summarized in Table 1 below.

The channel allocation status of each layer node is defined as a binary variable.

5.1 Tier1 Protection

The formula for the protection condition of layer 1 is expressed as follows.

는

에 따른 간섭량이고,

는 tier1의 interference threshold이다. 수식4에 따르면 해당 조건일 때만 계층1과 계층2가 같은 채널(=1)을 사용하여 공간적으로 공유를 하며, 수식5에 따르면 마찬가지로 해당 조건일 때만 계층1과 계층3은 같은 채널을 사용한다. 다른 채널(=0)인 경우 조건없이 사용한다.

The

The amount of interference according to,

Is the interference threshold of tier1. According to Equation 4, Layer 1 and Layer 2 use the same channel (=1) only when the condition is satisfied, and according to Equation 5, Layer 1 and Layer 3 use the same channel only when the condition is similar. In case of other channel (=0), it is used without condition.

5.2 Interference regulation

The formula for interference regulation when assigning channels is as follows.

는 SAS에 의해 통제되며

값이 크면 lower tier의 영향을 크게 고려한다는 의미이고,

값이 작으면 lower tier의 영향을 적게 고려한다는 의미이다. 수식7은 타 계층 간 다른 채널을 쓰도록 하는 조건이다.If the condition of Equation 6 is satisfied, the same channel can be used. That is, it is possible if the sum of the interference of the same tier and the interference of the lower tier is below a corresponding threshold.

Is controlled by SAS

If the value is large, it means that the influence of the lower tier is largely considered.

If the value is small, it means that the effect of lower tier is considered less. Equation 7 is a condition to use different channels between different layers.

5.3 Co-channel access regulation

)는 노드 간 공간적으로 멀리 떨어뜨려 놓아 간섭을 최소화한다. 이에 관한 수식은 아래와 같다.When Tier 3 uses the same channel (

) Minimizes interference by placing them far apart between nodes. The formula for this is as follows.

5.4 The number of channels

The number of available channels for Tier 2 and Tier 3 is defined as follows.

5.5 Channel allocation algorithm

The channel allocation algorithm is as follows. 1) The number of nodes in each tier, interference threshold, etc. are input. 2) Set the channel of Tier2 according to the constraints. 3) Set the channel of Tier 3 that satisfies the constraints.

The above description of the present invention is for illustration only, and a person having ordinary knowledge in the technical field to which the present invention pertains can understand that it can be easily modified to other specific forms without changing the technical spirit or essential features of the present invention. will be.

Therefore, it should be understood that the above-described embodiments are illustrative in all respects and not restrictive.

For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted to be included in the scope of the present invention.

Claims (1)

Registering the location, frequency of use, and transmission power of each layer in the license database;
Determining a channel allocation state for each layer; receiving a node number of each layer, an interference boundary value, and setting a channel of layer 2 and a channel of layer 3, a frequency access method for joint use of frequencies. .

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