JP4540646B2 - Relay station selection method, network control management apparatus, and program to which IEEE 802.16 is applied - Google Patents

Description

  The present invention relates to a relay station selection method, a network control management device, and a program to which IEEE 802.16 is applied.

  IEEE 802.16 is a standard for a high-speed wireless access system that can provide a BWA (Broadband Wireless Access) service. Currently, at the IEEE 802.16 standardization meeting, studies to define the media access control and the physical layer have been started regarding MMR (Mobile Multihop Relay) technology that expands the coverage range by relaying data. Yes. According to this MMR technique, a base station BS (Base Station) communicates with a fixed station SS (Subscriber Station) or a mobile station MS (Mobile Subscriber Station) within the base station BS and relays within the base station BS. It is also possible to communicate with a fixed station SS or a mobile station MS outside the base station BS area via a station RS (Relay Station).

  The IEEE 802.16 high-speed wireless access system is basically a standard for the purpose of providing a BWA service for a fixed station SS (for example, refer to Non-Patent Document 1, IEEE 802.16-2004). Here, two network topologies, PMP (Point-to-Multipoint) and Mesh, are defined. The PMP basically configures a network with “BS: SS = 1: Many” as in a general cellular system. On the other hand, Mesh configures a network of fixed stations SS by multi-hop.

  According to Non-Patent Document 1, no consideration is given to a relay function for the purpose of extending the coverage range. When relaying power amplification, the relay station RS simply amplifies and transfers a desired Burst Profile (modulation scheme and code rate information) determined by the communication state between the relay station RS and the fixed station SS. Therefore, the communication state between the base station BS and the relay station RS is not considered, and as a result, the match between the base station BS, the relay station RS, and the fixed station SS cannot be achieved.

  Further, the coverage range can be expanded by using the Mesh topology of the IEEE 802.16-2004 standard. However, Mesh is treated as an option, and the frame configuration is not compatible with PMP. In addition, compared with PMP, there is more frame overhead, which affects throughput. The duplex method supports only TDD (Time Division Duplex).

  Furthermore, there is a standard for a high-speed wireless system in which IEEE 802.16-2004 is modified for the purpose of providing a BWA service for a mobile station MS (for example, see Non-Patent Document 2, IEEE 802.16e-2005). As a modulation method, a single carrier, OFDM (Orthogonal Frequency Division Multiplexing), or OFDMA (Orthogonal Frequency Division Multiple Access) method is adopted. Only PMP is defined as the network topology.

  FIG. 1 is a system configuration diagram in the prior art.

  The mobile station MS can switch (handover) the base station BS to be connected while moving. According to FIG. 1, the target mobile station MS3 exists at a position where the coverage ranges of the three base stations BS overlap. At this time, the mobile station MS3 should be handed over to a base station BS that satisfies a desired QoS (Quality of Service). As the desired QoS, for example, there is a desired traffic rate.

  As a determination element for selecting the base station BS, an available radio resource ARR (Available radio resource) of the base station BS can be used. Available radio resource ARR refers to the ratio of average available subchannel and symbol resources per frame. The ARRs of all base stations BS are managed by a network control management system NCMS (Network Control Management System) 4. The network control management device NCMS4 controls the mobile station MS to connect to a base station BS having an available radio resource ARR that satisfies the desired QoS when handing over.

IEEE Std 802.16-2004, IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed Broadband Wireless Access Systems IEEE Std 802.16e-2005, IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface forFixed and Mobile Broadband Wireless Access Systems, Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1

  However, the network control management device NCMS manages the available radio resources ARR of the base station BS. When the relay station RS is arranged in a system to which IEEE 802.16 is applied, the network control management device NCMS It is not clear about the selection control. When the mobile station's desired QoS is not satisfied because the mobile station's traffic concentrates on any one of the relay stations RS connected to the base station BS even though there is a surplus in the available radio resource ARR of the base station BS Also occurs.

  Therefore, the present invention relates to a high-speed wireless access system to which IEEE 802.16 is applied, and when a mobile station MS performs handover by moving beyond the coverage range of the base station BS, a relay line (base station BS-relay station RS). It is an object of the present invention to provide a relay station selection method, a network control management device, and a program for selecting an access line (relay station RS) to be connected to the mobile station MS in consideration of the QoS between the mobile stations MS.

According to the present invention, for a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station, network control connected to the base station A relay station selection method in a management device,
When the mobile station communicates with the base station with the desired QoS, the network control management device
A first step of determining that a radio resource that can be used for communication with a subordinate relay station for a base station or a parent relay station is equal to or greater than a first traffic radio resource calculated from a desired QoS;
For the relay station determined to be true in the first step, it is determined that the radio resources available for communication with the subordinate mobile station or the child relay station are equal to or higher than the second traffic radio resource calculated from the desired QoS. A second step of:
And a third step of controlling the mobile station or the child relay station to connect to any one of the relay stations determined to be true in the second step.

According to another embodiment of the relay station selection method of the present invention,
The desired QoS of the mobile station is the desired traffic rate,
The available radio resource of the base station or the parent relay station is calculated from the desired traffic rate of all mobile stations communicating with the base station or the parent relay station and the modulation rate between the base station or the parent relay station and the relay station. , The percentage of free symbols per unit time,
The first traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the base station or the parent relay station and the relay station,
The available radio resources of the relay station are the number of free symbols per unit time calculated from the desired traffic rate of all mobile stations communicating with the relay station and the modulation rate between the relay station and the mobile station or the child relay station. The ratio of
The second traffic radio resource is also preferably a ratio of the number of traffic symbols per unit time calculated from a desired traffic rate of the mobile station and a modulation speed between the relay station and the mobile station or the child relay station.

According to another embodiment of the relay station selection method of the present invention,
It is also preferable that the network control management apparatus executes the first to third steps when the mobile station performs a handover exceeding the coverage range of the base station.

According to another embodiment of the relay station selection method of the present invention,
The desired traffic rate is included in DSA (Dynamic Service Addition) / DSC (Dynamic Service Change) / DSD (Dynamic Service Deletion) transmitted from the mobile station to the base station.
The modulation rate is the SGN-REP (Registration Request) when the relay station or mobile station registers with the base station, or the SCN-REP when the relay station or mobile station notifies the base station of the scan result of the surrounding situation. (Scanning Result Report)
The network control management device also preferably receives the desired traffic rate and modulation rate from the base station.

According to the present invention, there is provided a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station, and connected to the base station In the network control management device,
Network status receiving means for receiving network status information between stations from the base station;
A management means for managing network status information;
It is determined that the radio resource that can be used for communication with the subordinate relay station of the base station or the parent relay station is equal to or greater than the first traffic radio resource calculated from the desired QoS of the mobile station, and the determination is true. Determining means for determining that the radio resource available for communication with the subordinate mobile station or child relay station for the determined relay station is equal to or greater than the second traffic radio resource calculated from the desired QoS of the mobile station; ,
Network control means for controlling the mobile station or the child relay station to connect to any one of the relay stations determined to be true by the determination means .

According to another embodiment of the network control management device of the present invention,
The desired QoS of the mobile station is the desired traffic rate,
The available radio resource of the base station or the parent relay station is calculated from the desired traffic rate of all mobile stations communicating with the base station or the parent relay station and the modulation rate between the base station or the parent relay station and the relay station. , The percentage of free symbols per unit time,
The first traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the base station or the parent relay station and the relay station,
The available radio resources of the relay station are the number of free symbols per unit time calculated from the desired traffic rate of all mobile stations communicating with the relay station and the modulation rate between the relay station and the mobile station or the child relay station. The ratio of
The second traffic radio resource is also preferably a ratio of the number of traffic symbols per unit time calculated from a desired traffic rate of the mobile station and a modulation speed between the relay station and the mobile station or the child relay station.

According to another embodiment of the network control management device of the present invention,
A handover request receiving means for receiving a handover request of the mobile station from the base station and notifying the determination means to that effect;
The network control means preferably transmits a handover response including the identification information of the relay station determined by the determination means to the base station.

According to another embodiment of the network control management device of the present invention,
The desired traffic rate is included in DSA / DSC / DSD that the mobile station transmits to the base station.
The modulation rate is included in the REG-REQ when the relay station or mobile station registers with the base station, or in the SCN-REP when the relay station or mobile station notifies the base station of the scan result of the surrounding situation. And
The network control management device also preferably receives the desired traffic rate and modulation rate from the base station.

According to the present invention, there is provided a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station, and connected to the base station In a program for causing a computer installed in a network control management device to function,
Network status receiving means for receiving network status information between stations from the base station;
A management means for managing network status information;
It is determined that the radio resource that can be used for communication with the subordinate relay station of the base station or the parent relay station is equal to or greater than the first traffic radio resource calculated from the desired QoS of the mobile station, and the determination is true. Determining means for determining that the radio resource available for communication with the subordinate mobile station or child relay station for the determined relay station is equal to or greater than the second traffic radio resource calculated from the desired QoS of the mobile station; ,
The computer is caused to function as network control means for controlling a mobile station or a child relay station to connect to any one of the relay stations determined to be true by the determination means .

  According to the relay station selection method, network control management apparatus, and program of the present invention, when a mobile station MS performs handover by moving beyond the coverage range of a base station BS in a high-speed wireless access system to which IEEE 802.16 is applied. In addition, the access line (relay station RS) to be connected to the mobile station MS can be selected in consideration of the QoS of the relay line (between the base station BS and the relay station RS).

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a system configuration diagram according to the present invention.

  According to FIG. 2, compared with FIG. 1, there are two relay stations RS1 and RS2 under one base station BS. The base station BS can directly communicate with the mobile stations MS0-1 and MS0-2 and the relay stations RS1 and RS2. The relay station RS1 can communicate with the mobile stations MS1-1 and MS1-2, and the mobile stations MS1-1 and MS1-2 can communicate with the base station BS via the relay station RS1. Further, the relay station RS2 can communicate with the mobile stations MS2-1 and MS2-2, and the mobile stations MS2-1 and MS2-2 can communicate with the base station BS via the relay station RS2. Furthermore, a network control management device NCMS is connected to the base station BS.

  It is assumed that the target mobile station MS is moving in a direction exceeding the coverage range of the base station BS as shown in FIG. Further, the mobile station MS exists at a position where the coverage range of the relay station RS1 and the coverage range of the relay station RS2 overlap. In this case, the mobile station MS continues communication with the base station BS by switching the connection destination of the radio link from the base station BS to the relay station RS1 or RS2 (handover) before exceeding the coverage range of the base station BS. can do.

  At this time, it becomes a problem whether the mobile station MS should be connected to the relay station RS1 or the relay station RS2. According to the present invention, control is performed so as to connect to the relay station RS that satisfies the desired QoS of the mobile station MS. In FIG. 2, when viewed from the relay station, the base station may be a parent relay station, and the mobile station may be a child relay station. In other words, the present invention also supports multiple hops via multiple relay stations.

  FIG. 3 is an explanatory diagram showing the traffic rate in the system configuration of FIG.

According to FIG. 3, the mobile station MS has two paths for communicating with the base station BS.
(Route 1) Base station BS <-> Relay station RS1 <-> Mobile station MS
(Route 2) Base station BS <-> Relay station RS2 <-> Mobile station MS

  According to the present invention, it is determined whether or not the desired traffic rate of the mobile station MS can be secured in the path between stations in the order of hops from the base station BS. First, a route capable of securing the desired traffic of the mobile station MS is selected for the first hop link closest to the base station BS, and then a route is selected for the second hop link.

  In the following description, the desired QoS of the mobile station MS is described as a desired traffic rate because it is based on the OFDM scheme. However, it is not limited to the traffic rate, and delay or jitter can be considered.

Ｘ₀₁[bits/frame]：移動局ＭＳ０−１の所望トラヒックレート
Ｘ₀₂[bits/frame]：移動局ＭＳ０−２の所望トラヒックレート
Ｘ₁₁[bits/frame]：移動局ＭＳ１−１の所望トラヒックレート
Ｘ₁₂[bits/frame]：移動局ＭＳ１−２の所望トラヒックレート
Ｘ₂₁[bits/frame]：移動局ＭＳ２−１の所望トラヒックレート
Ｘ₂₂[bits/frame]：移動局ＭＳ２−２の所望トラヒックレート
Ｒ₀₁[bits/symbol]：基地局ＢＳ−移動局ＭＳ０−１間の変調速度
Ｒ₀₂[bits/symbol]：基地局ＢＳ−移動局ＭＳ０−２間の変調速度
Ｒ_A[bits/symbol]：基地局ＢＳ−中継局ＲＳ１間の変調速度
Ｒ_B[bits/symbol]：基地局ＢＳ−中継局ＲＳ２間の変調速度 First, the available radio resource a [%] of the base station BS is calculated based on the desired traffic rate of all mobile stations communicating with the base station and the modulation rate between the base station and the relay station. Is the ratio of the number of free symbols. In the following, “a ratio per frame” is calculated as an example of “per unit time”. The available radio resource a [%] of the base station BS is expressed by the following equation.

X ₀₁ [bits / frame]: desired traffic rate X ₀₂ of the mobile station MS0-1 [bits / frame]: desired traffic rate X ₁₁ of the mobile station MS0-2 [bits / frame]: desired traffic mobile station MS1-1 rate X ₁₂ [bits / frame]: desired traffic rate X ₂₁ of the mobile station MS1-2 [bits / frame]: desired traffic rate X ₂₂ of the mobile station MS2-1 [bits / frame]: desired mobile station MS2-2 Traffic rate R ₀₁ [bits / symbol]: Modulation speed between base station BS and mobile station MS0-1 R ₀₂ [bits / symbol]: Modulation speed between base station BS and mobile station MS0-2 R _A [bits / symbol ]: Modulation speed between base station BS and relay station RS1 R _B [bits / symbol]: Modulation speed between base station BS and relay station RS2

(Desired traffic rate [bits / frame] / modulation speed [bits / symbol]) represents the number of traffic symbols [symbols / frame] per frame. Since the base station BS communicates with the mobile stations MS0-1, MS0-2, MS1-1, MS1-2, MS2-1, and MS2-2, all of these traffic symbol numbers [symbols / frame] It is necessary to calculate the sum. The number of traffic symbols of the mobile stations MS1-1 and MS1-2 is calculated by the modulation rate R _A between the base station BS and the relay station RS1. Further, the number of traffic symbols of mobile stations MS2-1 and MS2-2 are calculated by the modulation rate R _B between the base station BS- RS RS2. (Total number of traffic symbols [symbols / frame] / number of data symbols [symbols / frame]) represents the ratio of used radio resources per frame. Further, 1- (ratio of used radio resources per frame) represents a ratio of free radio resources, that is, a ratio of available radio resources.

Ｘ[bits/frame]：移動局ＭＳの所望トラヒックレート
Ｒ_A[bits/symbol]：基地局ＢＳ−中継局ＲＳ１間の変調速度 (Route 1) It is determined whether or not the desired traffic rate of the mobile station MS can be secured between the base station BS and the relay station RS1. When the following equation is satisfied, the mobile station MS determines that the desired traffic rate can be secured between the base station BS and the relay station RS1. The first traffic radio resource (left side) is the ratio of the number of traffic symbols per frame calculated from the desired traffic rate of the mobile station and the modulation rate between the base station BS and the relay station RS1.

X [bits / frame]: Desired traffic rate of mobile station MS R _A [bits / symbol]: Modulation rate between base station BS and relay station RS1

(X [bits / frame] / R _A [bits / symbol]) represents the number of traffic symbols [symbols / frame] per frame in the mobile station MS. (The number of traffic symbols [symbols / frame] / number of data symbols [symbols / frame] of the mobile station MS) represents the ratio of radio resources used per frame of the mobile station MS. If the ratio of the radio resources used by the mobile station MS is equal to or less than the ratio of the radio resources available by the base station BS, the mobile station MS can secure the desired traffic rate between the base station BS and the relay station RS1. judge.

Ｘ[bits/frame]：移動局ＭＳの所望トラヒックレート
Ｒ_B[bits/symbol]：基地局ＢＳ−中継局ＲＳ２間の変調速度 (Route 2) It is determined whether or not the desired traffic rate of the mobile station MS can be secured between the base station BS and the relay station RS2. When the following equation is satisfied, the mobile station MS determines that the desired traffic rate can be secured between the base station BS and the relay station RS2.

X [bits / frame]: desired traffic rate R _B of the mobile station MS [bits / symbol]: modulation rate between the base station BS- RS RS2

  If it is determined that the desired traffic rate of the mobile station MS can be secured for both the route 1 and the route 2, the second hop is determined for both routes. When it is determined that the desired traffic rate of the mobile station MS cannot be secured for one of the route 1 and the route 2, the second hop is determined only for the other route. When it is determined that the desired traffic rate of the mobile station MS cannot be secured for both the route 1 and the route 2, the mobile station MS determines that the desired traffic rate cannot be secured even when connected to the relay station RS1 or RS2, and performs processing. finish.

Ｘ₁₁[bits/frame]：移動局ＭＳ１−１の所望トラヒックレート
Ｘ₁₂[bits/frame]：移動局ＭＳ１−２の所望トラヒックレート
Ｒ₁₁[bits/symbol]：中継局ＲＳ１−移動局ＭＳ１−１間の変調速度
Ｒ₁₂[bits/symbol]：中継局ＲＳ１−移動局ＭＳ１−２間の変調速度 (Route 1) Next, the available radio resource b [%] of the relay station RS1 is determined from the desired traffic rate of all mobile stations communicating with the relay station RS1 and the modulation rate between the relay station RS1 and the mobile station MS. This is the ratio of the number of empty symbols calculated per frame. The available radio resource b [%] of the relay station RS1 is expressed by the following equation.

X ₁₁ [bits / frame]: Desired traffic rate of mobile station MS1-1 X ₁₂ [bits / frame]: Desired traffic rate of mobile station MS1-2 R ₁₁ [bits / symbol]: Relay station RS1-mobile station MS1- Modulation speed between 1 R ₁₂ [bits / symbol]: Modulation speed between relay station RS1 and mobile station MS1-2

Ｘ[bits/frame]：移動局ＭＳの所望トラヒックレート
Ｒ_C[bits/symbol]：中継局ＲＳ１−移動局ＭＳ間の変調速度 It is determined whether or not the desired traffic rate of the mobile station MS can be secured between the relay station RS1 and the mobile station MS. When the following equation is satisfied, the mobile station MS determines that the desired traffic rate can be secured between the relay station RS1 and the mobile station MS. The second traffic radio resource (left side) is the ratio of the number of traffic symbols per frame calculated from the desired traffic rate of the mobile station and the modulation rate between the relay station RS1 and the mobile station MS.

X [bits / frame]: Desired traffic rate of mobile station MS R _C [bits / symbol]: Modulation rate between relay station RS1 and mobile station MS

Ｘ₂₁[bits/frame]：移動局ＭＳ２−１の所望トラヒックレート
Ｘ₂₂[bits/frame]：移動局ＭＳ２−２の所望トラヒックレート
Ｒ₂₁[bits/symbol]：中継局ＲＳ２−移動局ＭＳ２−１間の変調速度
Ｒ₂₂[bits/symbol]：中継局ＲＳ２−移動局ＭＳ２−２間の変調速度 (Route 2) The available radio resource c [%] of the relay station RS2 is calculated from the desired traffic rate of all mobile stations communicating with the relay station RS2 and the modulation rate between the relay station RS2 and the mobile station. This is the ratio of the number of empty symbols per frame. The available radio resource c [%] of the relay station RS2 is expressed by the following equation.

X ₂₁ [bits / frame]: desired traffic rate X ₂₂ of the mobile station MS2-1 [bits / frame]: desired traffic rate R ₂₁ of the mobile station MS2-2 [bits / symbol]: relay station RS2- mobile station MS2- 1 modulation rate R ₂₂ [bits / symbol]: modulation rate between relay station RS2 and mobile station MS2-2

Ｘ[bits/frame]：移動局ＭＳの所望トラヒックレート
Ｒ_D[bits/symbol]：中継局ＲＳ２−移動局ＭＳ間の変調速度 It is determined whether the desired traffic rate of the mobile station MS can be secured between the relay station RS2 and the mobile station MS. When the following equation is satisfied, the mobile station MS determines that the desired traffic rate can be secured between the relay station RS2 and the mobile station MS. The second traffic radio resource (left side) is the ratio of the number of traffic symbols per frame calculated from the desired traffic rate of the mobile station and the modulation speed between the relay station RS2 and the mobile station MS.

X [bits / frame]: Desired traffic rate of mobile station MS R _D [bits / symbol]: Modulation rate between relay station RS2 and mobile station MS

  Here, if it is determined that the desired traffic rate of the mobile station MS can be ensured for both the relay station RS1 and the relay station RS2, any route can be selected. However, the mobile station MS is preferably connected to a relay station having a large available radio resource. When it is determined that one of the relay station RS1 and the relay station RS2 cannot secure the desired traffic rate of the mobile station MS, the other relay station is selected. When it is determined that the desired traffic rate of the mobile station MS cannot be secured for both the relay station RS1 and the relay station RS2, the mobile station MS cannot secure the desired traffic rate even when connected to the relay station RS1 or RS2.

  FIG. 4 is a sequence diagram in the network entry of the relay station. Note that a solid arrow message represents a message already defined in Non-Patent Document 2. A dotted arrow message represents a message newly added in addition to the one already defined in Non-Patent Document 2 in order to realize the present invention via the relay station RS.

(S401) First, the base station BS broadcasts DL-MAP (DownLink-Map) and UL-MAP (UpLink-Map). DL-MAP is downlink allocation information, and UL-MAP is uplink allocation information.
(S402) The relay station RS1 that has received the DL-MAP and UL-MAP transmits an RNG-REQ (Ranging Request) to the base station BS, and receives an RNG-RSP (Ranging Response) from the base station BS. . Also, the relay station RS1 transmits an SBC-REQ (SS Basic Capability Request) to the base station BS, and receives an SBC-RSP (SS Basic Capability Response) from the base station BS.

(S403) Next, the relay station RS1 transmits a REG-REQ (Registration Request) to the base station BS. The REG-REQ has the following information.
REG-REQ_Message_Format () {
Management Message Type = 6 (8 bits)
TLV Encoded Information (TLV specific)
}

The following information is included in TLV Encoded Information of REG-REQ.
-MAC address of relay station RS-Base station ID / parent relay station ID to which the relay station RS is connected
・ Downlink Burst Profile (DIUC value: ID specifying modulation speed)
・ Uplink Burst Profile (UIUC value: ID specifying modulation speed)

(S404) Receiving REG-REQ, the base station BS transmits ROUTE-NOTIFY including information of TLV Encoded Information to the network control management device NCMS. The network control management device NCMS registers the network state information between the base station BS and the relay station RS1 from DIUC and UIUC.

(S405) In response to this, the network control management device NCMS returns a ROUTE-ACK to the base station BS. The ROUTE-ACK includes the following information.
-Number of hops-DIUC value for each hop-UIUC value for each hop-Cell ID assigned to relay station RS

(S406) The base station BS that has received the ROUTE-ACK returns a REG-RSP to the relay station RS1. The REG-RSP has the following information.
REG-RSP_Message_Format () {
Management Message Type = 6 (8 bits)
Response
TLV Encoded Information (TLV specific)
}
TLV Encoded Information includes information received by ROUTE-ACK.

(S407) The relay station RS2 that can directly communicate with the base station BS takes the same network entry sequence as that of S402 to S406 described above. Thereby, the network control management device NCMS registers the network state information between the base station BS and the relay station RS2.

(S408) The child relay station that cannot communicate directly with the base station BS makes a network entry to the base station BS via the relay station RS1 according to FIG. The child relay station transmits an RNG-REQ to the relay station RS1 and receives an RNG-RSP from the relay station RS1. Further, the child relay station transmits an SBC-REQ to the relay station RS1. The relay station RS that has received the SBC-REQ transmits SBC-NOTIFY to the base station BS. In response to this, the base station BS returns an SBC-ACK to the relay station RS1. The relay station RS1 returns SBC-RSP to the child relay station.

(S409) In response, the child relay station transmits a REG-REQ to the relay station RS1.
(S410) The relay station RS1 that has received the REG-REQ transmits REG-NOTIFY to the base station BS.
(S411) The base station BS transmits ROUTE-NOTIFY to the network control management device NCMS. Thereby, the network control management device NCMS registers the network status information between the child relay station-relay station RS1 and the base station BS.
(S412) The network control management device NCMS returns ROUTE-ACK to the base station BS.
(S413) The base station BS that has received the ROUTE-ACK transmits REG-NOTIFY to the relay station RS1.
(S414) The relay station RS1 that has received REG-NOTIFY transmits REG-RSP to the child relay station.

  Although not shown in FIG. 4, the mobile station MS sends a DSA-REQ (or DSC-REQ / DSD-REQ) to the base station BS in order to request a desired QoS after completing the network entry for the base station BS. Send. This is a conventional technique described in Non-Patent Document 2, and the base station BS can know the desired QoS of the mobile station MS.

  FIG. 5 is a sequence diagram showing collection of network state information and determination at the time of handover in the present invention. Note that the solid-line arrow message has already been defined in Non-Patent Document 2, and the dotted-line arrow message represents a message that is necessary for realizing the present invention via the relay station RS.

(S501) The base station BS periodically broadcasts MOB-NBR-ADV (Neighbor Advertisement) including neighboring connection destination information regarding neighboring base stations BS and relay stations RS. The mobile station MS knows the relay stations RS1 and RS2 existing in the vicinity from the received MOB-NBR-ADV.

(S502) Upon receiving MOB-NBR-ADV, the relay station RS and the mobile terminal MS transmit MOB-SCN-REQ (Scanning Interval Allocation Request) to the base station BS in order to acquire network state information. The base station BS that has received the MOB-SCN-REQ returns a MOB-SCN-RSP (Scanning Interval Allocation Response) to the mobile station MS and notifies the scan interval. Thereby, the mobile station MS starts scanning, and acquires network state information (information such as a reception level and an interference level from each station) in the relay stations RS1 and RS2 that are neighboring connection destinations. The relay station RS and the mobile station MS transmit SCN-REP (Scanning Result Report) including network state information collected by scanning to the base station BS. When receiving the SCN-REP from the relay station RS and the mobile station MS, the base station BS transmits ROUTE-NOTIFY to the network control management device NCMS. Thereby, the network control management device NCMS can collect and register network state information between stations.

(S503) When handing over, the mobile station MS transmits MOB-MSHO-REQ (MS HO Request) with network state information added to the base station BS. When receiving the MOB-MSHO-REQ from the mobile station MS, the base station BS recognizes it as a handover start request.

(S504) The base station BS transmits MOB-MSHO-REQ to the network control management device NCMS. The network control management device NCMS performs the determination processing described in FIG. 3 in order to select a relay station that satisfies the desired QoS of the mobile station MS based on the network state information.

(S505) The network control management device NCMS returns a MOB-BSHO-RSP (BS HO Response) including connection destination information of the relay stations RS1 and / or RS2 that can be used as a handover destination of the mobile station MS to the base station BS. .

(S506) The base station BS returns the MOB-BSHO-RSP to which the connection destination information of the mobile station MS is added to the mobile station MS.

(S507) The mobile station MS transmits MOB-HO-IND (HO Indication) including the connection destination information of the relay station RS1 or RS2 as the handover destination to the base station BS.
(S508) The base station BS transmits MOB-HO-IND to the network control management device NCMS. Thereby, the mobile station MS can be handed over to the relay station RS1 or RS2.

  FIG. 6 is a functional configuration diagram of the network control management device NCMS in the present invention.

  According to FIG. 6, the network control management device NCMS has a network state reception unit 41, a management unit 42, a handover request reception unit 43, a determination unit 44, and a handover response transmission unit 45 serving as a network control unit. . These functional units can also be realized by a program executed by a computer installed in the network control management device NCMS.

  The network state receiving unit 41 receives ROUTE-NOTIFY from the base station BS and returns ROUTE-ACK. ROUTE-NOTIFY includes network state information including a modulation rate between stations. The network state receiving unit 41 notifies the management unit 42 of the network state information.

  The management unit 42 accumulates and manages a desired traffic rate that is network state information and a modulation speed between stations.

  The handover request receiver 43 receives MOB-MSHO-REQ from the mobile station MS from the base station BS. At this time, the handover request receiving unit 43 instructs the determination unit 44 to determine the relay station that is the handover destination of the mobile station MS.

  The determination unit 44 determines that the available radio resource of the base station or the parent relay station is equal to or higher than the first traffic radio resource calculated from the desired traffic rate and the modulation rate between the base station and the relay station. For each relay station determined to be true, the available radio resource of the relay station is equal to or higher than the second traffic radio resource calculated from the desired traffic rate and the modulation rate between the relay station and the mobile station or the child relay station. Is determined.

  The handover response transmitter 45 serving as the network controller returns a MOB-BSHO-RSP including any one piece of identification information of the relay station determined to be true to the base station BS. On the other hand, the handover response transmission unit 45 receives MOB-HO-IND, which is a notification from the mobile station MS, from the base station BS. Thereby, the mobile station or the child relay station can be connected to the relay station RS that satisfies the desired QoS.

  As described above in detail, according to the relay station selection method, network control management apparatus, and program of the present invention, the mobile station MS has the coverage area of the base station BS in the high-speed wireless access system to which IEEE 802.16 is applied. When performing handover by moving beyond, it is possible to select an access line (relay station RS) to which the mobile station MS should be connected in consideration of the QoS of the relay line (between the base station BS and the relay station RS). .

  According to the various embodiments of the present invention described above, those skilled in the art can easily make various changes, modifications and omissions within the scope of the technical idea and the viewpoint of the present invention. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

It is a system block diagram in a prior art. It is a system configuration diagram in the present invention. It is explanatory drawing showing the traffic rate in the system configuration | structure of FIG. It is a sequence diagram in the network entry of a relay station. It is a sequence diagram showing collection of network state information and determination at the time of handover in the present invention. It is a functional block diagram of the network control management apparatus NCMS in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base station 2 Relay station 3 Mobile station 4 Network control management apparatus 41 Network state receiving part 42 Management part 43 Handover request receiving part 44 Judgment part 45 Handover response transmission part, network control part

Claims (9)

Relay system selection in a network control management apparatus connected to a base station for a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station A method,
When the mobile station communicates with the base station with the desired QoS, the network control management device
A first step of determining that a radio resource that can be used for communication with a subordinate relay station for a base station or a parent relay station is equal to or greater than a first traffic radio resource calculated from the desired QoS;
Radio resources that can be used for communication with a subordinate mobile station or a child relay station for the relay station determined to be true in the first step are equal to or greater than the second traffic radio resource calculated from the desired QoS. A second step of determining
A relay station selection method comprising: a third step of controlling a mobile station or a child relay station to connect to any one of relay stations determined to be true in the second step. The desired QoS of the mobile station is a desired traffic rate,
The available radio resource of the base station or the parent relay station is calculated from the desired traffic rate of all mobile stations communicating with the base station or the parent relay station and the modulation rate between the base station or the parent relay station and the relay station. , The percentage of free symbols per unit time,
The first traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the base station or the parent relay station and the relay station,
The available radio resources of the relay station are the number of free symbols per unit time calculated from the desired traffic rate of all mobile stations communicating with the relay station and the modulation rate between the relay station and the mobile station or the child relay station. The ratio of
The second traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the relay station and the mobile station or the child relay station. The relay station selection method according to claim 1.   3. The relay station selection method according to claim 1, wherein the network control management device executes the first to third steps when the mobile station performs handover exceeding the coverage range of the base station. . The desired traffic rate is included in DSA (Dynamic Service Addition) / DSC (Dynamic Service Change) / DSD (Dynamic Service Deletion) transmitted from the mobile station to the base station,
The modulation speed is the REG-REQ (Registration Request) when the relay station or mobile station registers with the base station, or the SCN- when the relay station or mobile station notifies the base station of the scan result of the surrounding situation. Included in REP (Scanning Result Report)
4. The relay station selection method according to claim 1, wherein the network control management device receives the desired traffic rate and the modulation rate from a base station. 5. In a network control management apparatus connected to a base station in a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station,
Network status receiving means for receiving network status information between stations from the base station;
Management means for managing the network status information;
It is determined that the radio resource that can be used for communication with the subordinate relay station of the base station or the parent relay station is equal to or greater than the first traffic radio resource calculated from the desired QoS of the mobile station, and the determination is true. Judgment that the radio resource that can be used for communication with a subordinate mobile station or a child relay station for the determined relay station is equal to or greater than the second traffic radio resource calculated from the desired QoS of the mobile station Means,
A network control management apparatus comprising: network control means for controlling a mobile station or a child relay station to connect to any one of the relay stations determined to be true by the determination means . The desired QoS of the mobile station is a desired traffic rate,
The available radio resource of the base station or the parent relay station is calculated from the desired traffic rate of all mobile stations communicating with the base station or the parent relay station and the modulation rate between the base station or the parent relay station and the relay station. , The percentage of free symbols per unit time,
The first traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the base station or the parent relay station and the relay station,
The available radio resources of the relay station are the number of free symbols per unit time calculated from the desired traffic rate of all mobile stations communicating with the relay station and the modulation rate between the relay station and the mobile station or the child relay station. The ratio of
The second traffic radio resource is a ratio of the number of traffic symbols per unit time calculated from the desired traffic rate of the mobile station and the modulation speed between the relay station and the mobile station or the child relay station. The network control management device according to claim 5. A handover request receiving means for receiving a handover request from a mobile station from the base station and notifying the determination means to that effect;
The network control management device according to claim 5 or 6, wherein the network control unit transmits a handover response including identification information of the relay station determined by the determination unit to the base station. The desired traffic rate is included in DSA (Dynamic Service Addition) / DSC (Dynamic Service Change) / DSD (Dynamic Service Deletion) transmitted from the mobile station to the base station,
The modulation speed is the REG-REQ (Registration Request) when the relay station or mobile station registers with the base station, or the SCN- when the relay station or mobile station notifies the base station of the scan result of the surrounding situation. Included in REP (Scanning Result Report)
8. The relay station selection method according to claim 5, wherein the network control management device receives the desired traffic rate and the modulation rate from a base station. In a system having a base station to which IEEE 802.16 is applied, a plurality of relay stations communicating with the base station, and a mobile station communicating with the relay station, mounted on a network control management apparatus connected to the base station In a program that causes a computer to function,
Network status receiving means for receiving network status information between stations from the base station;
Management means for managing the network status information;
It is determined that the radio resource that can be used for communication with the subordinate relay station of the base station or the parent relay station is equal to or greater than the first traffic radio resource calculated from the desired QoS of the mobile station, and the determination is true. Judgment that the radio resource that can be used for communication with a subordinate mobile station or a child relay station for the determined relay station is equal to or greater than the second traffic radio resource calculated from the desired QoS of the mobile station Means,
A network control management apparatus for causing a computer to function as network control means for controlling a mobile station or a child relay station to connect to any one of relay stations determined to be true by the determination means program.

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