KR20160052980A - Method and apparatus for determining path for SHF/EHF band communication in cellular overlay network - Google Patents

Abstract

A method to set up a path and an apparatus thereof are provided. In a wireless network forming a multi-level cell, candidate links capable of being connected to to a terminal among links between a terminal and base stations based on channel quality information received from the terminal accessing the wireless network are selected. Optimal links including at least one link to connect with the terminal based on the order of priority of the selected candidate links and path information related with the selected optimal link is transmitted to the terminal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a path setting method and apparatus for SHF / EHF band communication in a cellular overlay network,

The present invention relates to a method and apparatus for routing in a cellular overlay network, and to a method and apparatus for routing in a cellular overlay network for SHF / EHF (Super High Frequency to Extremely High Frequency) communication.

As the mobile traffic increases, the miniaturization of the cell becomes more serious, and as the cell radius decreases, the inter-cell interference phenomenon and the handover operation frequently become frequent, so that the system load increase problem and, in some cases, This can lead to serious conditions that can happen.

Therefore, there is a limitation in using only the cellular frequency band, and it is necessary to utilize the SHF / EHF (High Frequency to Extremely High Frequency) band from the viewpoint of finding a new frequency resource.

In the case of the SHF / EHF band, it is possible to realize a narrow beam based on the mmWave band, thereby greatly reducing interference and handover problems, and at the same time, miniaturization of the cell is possible. Strong linearity in the SHF / EHF band, which is a millimeter-wave propagation characteristic, should ensure the line-of-sight for communication.

Also, when using the millimeter band of SHF / EHF as a mobile communication means, when constructing a multi-level cell topology for securing the visible distance between the base station and the terminal, the terminal moves to the beam- When entering, there is a sudden quality deterioration in the communicating channel. Accordingly, if rapid handover is not provided, a large amount of traffic data may be lost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for setting an optimal path for a fast handover when a multi-level cell topology is configured in a cellular overlay network.

A path setting method according to an aspect of the present invention is a method of setting a path for SHF / EHF (Super High Frequency to Extremely High Frequency) communication in a wireless network constituting a multilevel cell, Receiving channel quality information based on a pilot signal of the SHF / EHF band from the base stations from the base stations; Selecting a candidate link connectable to the terminal based on channel quality information for each link between the terminal and each base station; Selecting an optimal link including at least one link for connection with the terminal based on the ranking of the selected candidate links; And transmitting the optimal link related path information to the terminal.

According to an embodiment of the present invention, when constructing a multi-level cell topology in a cellular overlay network, it is possible to optimize the channel quality between the UE and multiple base station beam links periodically or when necessary using the cellular band and the SHF / The link information can be secured for each rank. Therefore, even when the terminal enters a sudden non-visible range or enters a beam-edge, a seamless handover is possible. Therefore, performance of system performance and user service quality can be improved.

1 is a conceptual diagram of a wireless communication system using a cellular frequency band and an SHF / EHF band simultaneously according to an embodiment.
2 is a diagram illustrating a multi-stage cell configuration in which a central base station and a relay base station are physically overlapped in a central network wireless communication environment according to an exemplary embodiment of the present invention.
3 is a flowchart illustrating a process of receiving downlink data of a terminal according to the routing of the embodiment of the present invention.
FIG. 4 is a flowchart of a process of transmitting uplink data of a UE according to the routing of the embodiment of the present invention.
5 is an illustration of a resource management table for managing the quality status of wireless links according to an embodiment of the present invention.
6 is a flowchart of a path setting method according to an embodiment of the present invention.
7 is a structural diagram of a route setting apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification and claims, when a section is referred to as including an element, it is understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Throughout the specification, a terminal is referred to as a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR- A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE) , HR-MS, SS, PSS, AT, UE, and the like.

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station (HR) A femto BS, a home Node B, a HNB, a pico BS, a metro BS, a micro BS, ), Etc., and may be all or part of an ABS, a Node B, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, an RS, an RN, an ARS, It may include a negative feature.

Hereinafter, a path setting method and apparatus according to an embodiment of the present invention will be described.

1 is a diagram illustrating a network environment according to an embodiment of the present invention. 1 shows a wireless communication system using the cellular frequency band and the SHF / EHF band at the same time.

1, a central network is formed in the embodiment of the present invention, and the central network includes a central base station 1, a terminal 2, and relay base stations 31 to 33. The central network is a mobile communication network that simultaneously supports the cellular band and the SHF / EHF (Super High Frequency to Extremely High Frequency) band while managing the network from the center.

The central base station 1 corresponds to a general parent base station, and the relay base stations 31 to 33 perform a relay role by using a wireless link between a terminal and a central base station. Different frequency bands are used at different cell levels on the topology to minimize cell-to-cell interference in multi-level overlay configurations.

1, the terminal 2 is placed at a non-visible distance by a building located between the terminal 2 and the central base station 1, and direct beam transmission / reception between the terminal 2 and the central base station 1 It is impossible to set the route. In this case, the terminal 2 and the central base station 1 can be connected through the relay base station 33, which is the next lower step on the topology.

In this manner, a multi-stage relay base station topology is configured so that one or more beam paths can be secured in most terminal positions by utilizing the overlapping topology characteristic using a multi-stage relaying method between the terminal and the base station through the multi-level cell configuration. A communication environment between the terminal and the base station can be established.

2 is a diagram illustrating a multi-stage cell configuration in which a central base station and a relay base station are physically overlapped in a central network wireless communication environment according to an embodiment of the present invention.

Beamforming in the base station 1 covers the cell represented by the cell layer 1 (S1), beamforming in the relay base station 31 covers the cell represented by the cell layer 2 (S2) ) May cover the cell represented by the cell layer 3 (S3).

Accordingly, the terminal 2 can form multi-beam with the central base station 1, the relay base station 1 31, and the relay base station 2 32 according to the respective positions. Although FIG. 2 shows that the terminal 2 can be concurrently connected to the base station through a maximum of three beams, the present invention is not limited thereto.

Each of the cell layers in FIG. 2 can dynamically reduce or enlarge the coverage according to the communication environment such as the terminal status in the cell, or may be set to operate limitedly as needed to reduce the power consumption.

In the network environment according to the embodiment of the present invention, the cellular frequency band and the SHF / EHF band can be used simultaneously. The SHF / EHF frequency band, which is basically required for the control channel, is allocated for the stable cellular frequency band in which the visibility is not required to be secured, and for the high-speed traffic channel, It is possible to provide the transmission rate and the service quality desired by the subscriber.

Table 1 shows a resource allocation scheme for a control channel and a traffic channel used between a UE and a BS in a wireless network environment using the cellular band and the SHF / EHF band in common.

Since the terminal operates in multi-band / mode, the cellular band or the SHF / EHF band can be set to the use mode as shown in Table 1 according to the radio environment (including LoS) and QoS at the initial stage of communication attempt.

Referring to Table 1, there are two types of methods, that is, an initial mode and a mature mode, in which frequency bands used for initial call setup and subsequent traffic assignment are different.

First, in the initial mode, the initial call setup uses the cellular band, and then the traffic allocation allocates the SHF / EHF band, or the initial call setup and the low light traffic allocate the cellular band and then the high- The SHF / EHF band is additionally allocated. This initial mode may be a method in which a common resource manager of a base station existing in a backbone network is determined based on a multi-path finder with the help of a terminal. In the case of the mature mode, the SHF / EHF band can be allocated to all kinds of traffic after initial call setup.

Next, a path setting method for SHF / EHF band communication in a cellular overlay network according to an embodiment of the present invention will be described.

3 is a flowchart illustrating a process of receiving downlink data of a terminal according to the routing of the embodiment of the present invention. In particular, in FIG. 3, an optimal link-beam is selected between a terminal in a SHF / EHF band and a plurality of multi-level base stations through control of a cellular band for a downlink, and traffic transmission through an optimal link is performed.

The terminal 2 receives the paging channel from the central base station 1 through the cellular band (S100 and S110), and receives a plurality of pilot signals transmitted through the SHF / EHF band from the adjacent central base station and the relay base stations (S120 , S130). Then, based on the received pilot signals, the channel quality of each wireless link between each base station and the terminal is measured (S140). The channel quality information measured here includes Received Signal Strength Indicator (RSSI), signal to noise ratio (SNR), and signal to interference ratio (SIR).

The terminal 2 reports the measurement results for each radio link, and reports the channel quality information measured for each radio link to the central base station 1 through the cellular band (S150). For example, the terminal 2 receives all of the pilot signals in the SHF / EHF band transmitted from the base stations, measures the received signals, and outputs measurement results including channel quality information based on the received pilots together with its identification information And report it to the base station 1.

Based on the channel quality information, the central base station 1 manages the quality state of the radio links measured by each terminal (S160). Specifically, the central base station 1 registers or updates the quality status of the radio links in an information table, for example, a resource management table, which manages the quality of the radio links, and sets the link cost according to the channel quality, the surplus radio resource, (For example, in the embodiment of the present invention, the grade can be divided into 16 grades, the grade 0 indicates the least cost, and the grade 15 indicates that the largest cost is required) (S170 ).

In step S180, the central base station 1 selects the optimal multi-path between the terminal and the base station according to the selection algorithm in step S180, and transmits the selection result to the terminal 2 through the cellular band. The selection result includes the terminal-to-base station communication link information according to the optimal multi-path. The selection of the optimum multipath will be described later in more detail.

The terminal 2 receives the information on the optimal multi-path and performs setting to the selected optimal multi-path (S200). And receives traffic channel data from the corresponding base station through the SHF / EHF band (S210, S220). Thereafter, the terminal 2 cancels the link setting (S230).

FIG. 4 is a flowchart of a process of transmitting uplink data of a UE according to the routing of the embodiment of the present invention. In particular, in FIG. 4, an optimal link-beam is selected between a terminal in the SHF / EHF band and a plurality of multi-level base stations through the control of the cellular band for the uplink, and traffic transmission through the optimal link is performed.

4, the terminal 2 receives a plurality of pilot signals transmitted through the SHF / EHF bands (S400 and S410), and transmits the pilot signals to the wireless base stations (E.g., RSSI, SNR, SIR, etc.) (S420) and report the measured result information to the base station 1 through the cellular band (S430).

The central base station 1 registers or updates the quality status of each radio link measured by each mobile station in the resource management table as described above, and then transmits the link cost according to the channel quality, the surplus radio resource, And classified into a predetermined grade and recorded (S440, S450). The central base station 1 selects the optimal multi-path between the terminal and the base station according to the selection algorithm in step S460 and transmits the selection result to the terminal 2 through the cellular band in step S470.

The terminal 2 transmits the random access channel to the selected base station based on the received selection result (S480, S490). The base station, which has received the random access channel from the terminal, transmits an ACK for establishing the communication link to the terminal through the cellular band (S510, S520). The terminal 2 transmits the traffic channel data in the SHF / EHF band (S530). The base station receives the traffic channel data transmitted from the terminal through the uplink (S540). Thereafter, the terminal 2 cancels the link setting (S550).

In the procedure as described above, the process of setting the optimal path based on the channel quality information by the base station will be described in more detail.

The central base station 1 manages the quality state of the wireless links based on the channel quality information provided from the terminal, and registers and manages the quality state of the wireless links in the resource management table.

5 is an illustration of a resource management table for managing the quality status of wireless links according to an embodiment of the present invention. In particular, FIG. 5 illustrates the channel quality and link cost management table for each available radio link used for resource management of the base station based on the channel-to-base station channel measurement information.

5, the channel quality and link cost management table for each available radio link includes a cell layer ID (T1), a base station ID (T2), a terminal ID (T3), a beam vector ID (T4) (T5), and link cost (T6).

The cell layer ID (T1) is an identifier for identifying the cell layer. The central base station can assign a cell layer ID to each cell layer in a direction in which an arbitrary value is set to an initial value and is incremented by 1 in the downward direction of the cell layer.

The base station ID (T2) is an identifier for identifying base stations included in the same cell layer. The terminal ID T3 indicates a terminal identifier mapped to a base station tuple of the corresponding management table.

The beam vector ID T4 indicates the beam number at the base station connecting the base station ID and the terminal ID. The channel quality T5 indicates the values of the channel quality information and specifically indicates the received signal strength (RSSI) and the attribute values of the signal-to-noise ratio (SNR) and the signal-to-interference ratio (SIR) in the corresponding link channel.

The link cost T6 is an attribute value used for determining the optimal link rank. Specifically, the link cost (T6) is used to set an optimal link rank with a certain level rank value in an area exceeding a threshold value per channel quality target and a virtual relative link usage cost determined by an available bandwidth (resource) of the link ≪ / RTI >

Based on the channel quality and link cost management table for each available radio link including such data, the central base station can establish an optimal link.

6 is a flowchart of a path setting method according to an embodiment of the present invention. In particular, FIG. 6 shows a procedure for updating the optimal link according to the priority based on the link information between the terminal and the base station from each terminal collected by the central base station.

In order to select an optimal path among the links included in the link forming table including information on the links between the terminal and the base station collected on the basis of the terminal, the central base station 1 sets the channel quality of an arbitrary link to a predetermined threshold value (S600, S610). For example, a line is patched on a tuple-by-tuple basis from the link formation table, and it is determined whether the channel quality of the link recorded in the patched line is greater than a preset threshold value Q. Here, the channel quality compared with the threshold may be at least one of received signal strength (RSSI), signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR) in the link channel.

If the channel quality of the link satisfies the minimum condition that can be set to the path because the channel quality is greater than the predetermined threshold value Q, the link cost of the link is compared with a preset threshold value C in step S620. If the link cost is greater than a preset threshold C and satisfies the minimum condition that can be set in the path, the link is set as the candidate link of the optimum path. Then, the ID of the cell layer to which the BS of the previously set candidate links belongs is compared with the ID of the cell layer to which the BS of the link set as the candidate link belongs, and a high priority is given to the link corresponding to the cell layer having the high ID value . That is, the higher the value of the ID of the cell layer to which the link belongs, the higher the priority is given (S630). This is because the links (or beams) preset and connected in advance between the central base station and the relay base station or the relay base station are in a fixed state and the link responsible for the other links can be connected to the central base station It is the door.

In step S640, the priority for each link managed in the path management table is updated in accordance with the determined priority for each link. The route management table is matched in priority order with respect to the links between the terminal and the base station.

Through the above process, priority is given to all links included in the link forming table through channel quality, link cost, and ID comparison of the cell layer (S650).

After completing the prioritization and update of all the links included in the link formation table, the central base station can select the links having the highest rank among the links described in the path management table and inform the terminal of the links. Therefore, based on the selective link related information provided from the central base station, the terminal can minimize the preparation of link setting in advance in case of a highest priority link failure, and can perform handover (beam switching) in a short delay time with a link of the next rank .

As described above, in the embodiment of the present invention, the UE periodically / non-periodically receives the pilot signals of the SHF / EHF band transmitted from the neighbor base stations, measures the channel quality of each link with each base station, To the central base station, the central base station selects an optimal terminal-base station radio link capable of being connected to the corresponding terminal according to the priority determination method, and informs the terminal of information on the selected link, Links can be configured to route and send and receive traffic.

7 is a diagram illustrating a configuration of a routing device according to an embodiment of the present invention.

7, the path setting apparatus 10 according to the embodiment of the present invention includes a channel quality information receiving unit 11, a link forming unit 12, a channel quality comparing unit 13, a link cost comparing unit 14, a priority assignment unit 15, a link selection unit 16, and a link information transmission unit 17.

The channel quality information receiving unit 11 receives channel quality information (RSSI, SNR, SIR, etc.) from a terminal. The channel quality information can be periodically / aperiodically transmitted from the UE, and is information generated by measuring the pilot signal of the SHF / EHF band transmitted from the base station.

The link forming unit 12 forms a radio link between base stations capable of communicating with the terminal. Selects base stations capable of communicating with the UE based on the channel quality information transmitted from the UE, and forms a radio link between the selected base station and the UE. Such radio link related information can be stored and managed in the link formation table.

The channel quality comparison unit 13 compares the channel quality for the wireless links formed between the terminal and the base station with a predetermined threshold (for example, may be referred to as a first threshold).

The link cost comparing section 14 compares the link cost for the wireless links formed between the terminal and the base station with a predetermined threshold (for example, may be referred to as a second threshold).

The priority assigning unit 15 gives priority to links satisfying the minimum condition that the channel quality and the link cost can be set to a path larger than the set thresholds. The priority assigning unit 15 compares the IDs of the cell layers of the candidate links satisfying the minimum condition and gives a high priority to the link corresponding to the cell layer having the high ID value. That is, the higher the value of the ID of the cell layer to which the link belongs, the higher the priority is given. Link-specific priorities can be stored and managed in the routing table.

The link selection unit 16 selects at least one path among the candidate links. For example, among the candidate links, it is possible to select links within a predetermined upper rank or to select a link having the highest rank.

The link information transmission section 17 generates information related to the links selected by the link selection section 16 and transmits the generated information to the terminal 2.

The path setting apparatus 10 according to the embodiment of the present invention having such a structure can be implemented as being included in the common resource manager of the central base station.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (1)

In a method for establishing a path for SHF / EHF (Super High Frequency to Extremely High Frequency) communication in a wireless network constituting a multilevel cell,
Receiving channel quality information based on a pilot signal of the SHF / EHF band received from the base stations from a terminal connected to the wireless network;
Selecting a candidate link connectable to the terminal based on channel quality information for each link between the terminal and each base station;
Selecting an optimal link including at least one link for connection with the terminal based on the ranking of the selected candidate links; And
And transmitting the optimal link related path information to the terminal
≪ / RTI >

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