KR101044617B1 - Scheduling methods and systems for multi-hop relay in wireless communications - Google Patents

Abstract

The wireless communication system includes one or more base stations, which includes at least one antenna for signal communication; A transceiver; And a communication control device. The transceiver is configured to receive and relay a first group of relay stations and a second group of wireless communication signals from at least one base station, the second group being configured to receive and relay from the at least one base station. Configured to communicate with the relay stations of the group. The communication control apparatus is configured to control at least one of (1) signal transmission power of at least one antenna and (2) signal communication timing of at least one antenna. The communication control device also divides the service period of the at least one antenna into multiple phases, permits communication of signals to or from the first group of relay stations in the first phase, and during at least a portion of the first phase. Configured to allow the second group of relay stations to communicate the signal independently from signals directed to or caused by the first group of relay stations.

Description

Scheduling methods and systems for multi-hop relay in wireless communications

Cross-reference to related application

This application is disclosed in US patent application Ser. No. 12 / 121,749, filed May 15, 2008, entitled "Scheduling methods and systems for wireless multi-hop relay communications." It claims priority to this application as a continuation-in-part application.

The present invention relates to a scheduling method and system for multi-hop relay in wireless communication. More particularly, the present invention relates to grouping relay stations in a wireless multi-hop communication system.

Modern and future mobile communication systems are designed to provide high speed, high link-quality, or high security transmission. In addition, they can support various communication needs, services or protocols. Efficient resource scheduling or allocation methods may need to meet various quality of service (QoS) requirements for different users at different points. For example, users located at cell boundaries or borders of wireless transmission may reduce link quality, and users in cells with extreme shadowing effects may also have reduced link quality. Without effective resource schedules or allocations, reduced link quality can prevent users from transmitting high data rates.

One way to solve this problem is to increase the density of the base station, or to increase the density of the base station or to place more base stations in an area having strict shadowing or low desirable link quality. This approach can increase costs or require additional equipment or hardware. As an alternative, the transmit power of the base station may be increased to increase link quality, but this solution may increase transmission cost, signal interference, or both.

As another solution, a multi-hop relay cell architecture can be implemented, which takes into account some of the problems in some applications, for example, considering factors such as QoS, deployment cost, transmit power and coverage area of the cell. Can solve the branches. The relay station may be disposed in a cell to relay information from the base station to the user or mobile station. In some applications, using relay stations can improve cell coverage, user throughput, system capacity, or a combination thereof over other alternatives. For example, a relay station may be located in an area where severe bird windowing occurs, an area near a cell boundary, an area not properly serviced by a base station, or an area with low desirable link quality. Hence, the relay station can more preferably serve this area by providing improved link quality or extend the effective coverage of the base station.

A single link with low desirable quality may be divided into a plurality of links with better quality to allow each link to provide a higher transmission rate. However, since the same data can be replicated or relayed multiple times using the public network for multi-hop transmission, this embodiment requires additional radio resources for additional hops for data transmission. Without the proper scheduling mechanism, this can consume more radio resources than single-hop systems.

In a multi-hop communication system, one base station and several relay stations may exist in one cell. In order to efficiently utilize radio resources and improve spectral efficiency, multiple serving stations can be activated simultaneously if the interference level is appropriate. For example, the interference may be (1) potential interference between serving stations (base stations and / or relay stations) transmitting within the same cell, (2) interference from such transmitting serving stations to other cells, or (1) and (2) may include all;

In order to obtain the advantages for a multi-hop relay communication system, there may be a need for a scheduling mechanism for transmission of base stations and relay stations. As an example to improve the performance of a wireless communication system, a method of installing a relay station in a Manhattan-like environment has been provided within the Wireless World Initiative new Radio (WINNER) program. An environment similar to Manhattan is a lattice environment with a block width of 200 meters (m) and a distance of 30 meters. 1 is a diagram illustrating the layout of a base station 205 and a plurality of relay stations 201-204 in a single cell in a Manhattan-like environment. Referring to FIG. 1, the base station 205 and the relay stations 201 to 204 may be arranged in a single cell. Base station 205 and relay stations 201-204 may communicate with users via an omni-directional antenna. However, because relay stations 201-204 can be located outside coverage area 206 of base station 205, each of relay stations 201-204 additionally points to base station 205 to communicate with base station 205. May require a directional antenna. This need can increase the hardware cost of the relay station.

FIG. 2 is a diagram illustrating transmission scheduling of a frame structure that may be applied to the first layout shown in FIG. 1 within a single cell. Referring to FIG. 2, frame S301 may be divided into two sub-frames S302 and S303. The first sub-frame S302 may also be further divided into five time slots S304 to S308. The base station 305 may provide services to the four relay stations 301 to 304, respectively, during the first four time slots S304 to S308. During the fifth time slot S308, the base station 305 may provide a service to the user within the area 306, which may communicate directly with the base station 305. The second sub-frame S303 can be divided into two time slots S309 and S310, and utilizing the feature of spatial separation of the environment, the relay stations 301 and 302 can individually separate during the first time slot S309. It is possible to provide services to their corresponding users in the two areas 307 and 308, and the relay stations 303 and 304 are individually their corresponding users in the two areas 309 and 310 during the second time slot S310. Can provide services to them.

FIG. 3 is a diagram showing the layout of base stations 405 and 415 and relay stations 401 to 404 and 411 to 414 in a multi-cell structure in a Manhattan-like environment shown in FIG. Referring to FIG. 3, the coverage area 406 of single cell A and the coverage area 416 of single cell B are arranged in a zigzag manner. Furthermore, the base stations 405 and 415 of FIG. 4 indicate the locations of the base stations in single cell A and single cell B. The relay stations 401-404 belong to a single cell A and the relay stations 411-414 belong to a single cell B.

4 is a diagram illustrating transmission scheduling for a frame structure applicable to the layout shown in FIG. 3 within a multi-cell structure in a Manhattan-like environment. Referring to FIG. 4, an arrangement of transmission frames between adjacent cells may be used to change or adjust the operation order of sub-frames S502 and S503 in frame S501, whereby intercell interference may be reduced. have. Such a relay station may extend the coverage area of the base station. However, the link quality of users at the service coverage boundary of the base station may not be improved or only limitedly. Furthermore, all of the base stations can have idle time within a period of frame transmission. Since the base stations may be the only serving station connected to the backhaul network and transmitting valid data, the transmission efficiency of the base station in this design may be less desirable.

FIG. 5 is a diagram illustrating a second layout of four relay stations 601-604 having base stations 605 and omnidirectional antennas in a Manhattan-like environment. Referring to FIG. 5, both the base station 605 and the relay stations 601-604 can communicate with a user using an omnidirectional antenna. Referring to Fig. 5, the base station 605 and the arbitration stations 601 to 604 communicate with the user by using an omnidirectional antenna. Because the relay stations 601-604 are located within the coverage area 606 of the base station 605, no additional directional antenna may be needed by each of the relay stations 601-604 to communicate with the base station 605. In this design, the link quality of users within the cell boundary can be improved.

FIG. 6 is a diagram illustrating transmission scheduling for a frame structure where the second layout shown in FIG. 5 is applicable to a layout with omnidirectional antennas in which all serving stations are similar to Manhattan. Referring to FIG. 6, the base station 705 may provide services to four relay stations 701 to 704 sequentially during the first four time slots S701 to S704, and at the same time, the base station 705 to the base station 705. It can also provide services to directly connected users. Relay stations 701 through 703 may individually provide services to their corresponding users during time slot S705. Thereafter, the base stations 702-704 can individually service their corresponding users during subsequent time slots S706. Such a layout may improve link quality of users located at cell boundaries. However, a complete transmission in a single cell may require at least six phases. Considering the multi-cell structure, since the omnidirectional antenna is used, at least two reuse factors may be required to avoid severe intercell interference, thereby reducing overall system capacity.

If the layout of the base station and the relay station is different, all base stations and relay stations may still be idle in the frame structure for a predetermined time. Therefore, transmission efficiency may not be desirable. Therefore, a need exists for a system and method for multi-hop relay in a wireless communication system that can provide alternative implementations or applications. Embodiments disclosed herein may overcome one or more of the problems as described above or may be configured to overcome the problems.

Embodiments disclosed herein may overcome one or more of the problems as described above or may be configured to overcome the problems.

In one exemplary embodiment, the disclosure disclosed herein relates to a wireless communication system including at least one base station configured to communicate with at least one user device via at least one relay station. The base station includes at least one antenna for signal communication; A transceiver; And a communication control device. The transceiver is configured to receive and relay a first group of relay stations and a second group of wireless communication signals from at least one base station, the second group being configured to receive and relay from the at least one base station. Configured to communicate with the relay stations of the group. The communication control apparatus is configured to control at least one of (1) signal transmission power of at least one antenna and (2) signal communication timing of at least one antenna. The communication control device also divides the service period of the at least one antenna into multiple phases, permits communication of signals to or from the first group of relay stations in the first phase, and during at least a portion of the first phase. And allow the second group of relay stations to communicate the signal independently from signals directed to or caused by the first group of relay stations.

In another exemplary embodiment of the present invention, the disclosure disclosed herein includes: a first group of relay stations configured to receive and relay a first group of wireless communication signals; A second group of relay stations configured to receive and relay a second group of wireless communication signals; And at least one base station configured to communicate with relay stations of the first group and relay stations of the second group. Relay stations in the first and second groups are divided into groups based at least on potential interference between relay stations in the same cell and from other serving stations in at least one co-channel cell. do. The base station includes a communication control device configured to control at least one of at least one antenna for signal communication and (1) signal transmission power of at least one antenna and (2) signal communication timing of at least one antenna. The communication control device divides the service period of the at least one antenna into at least two phases, permits communication of signals to or from the first group of relay stations in the first phase, and Configure the second group of relay stations to communicate with at least one user device and at least one base station independently from signals directed to or caused by the first group of relay stations during at least a portion of the first phase It is characterized by.

In another exemplary embodiment of the present invention, the subject matter disclosed herein relates to a method of wireless communication. The method of wireless communication includes establishing communication between at least one base station and a plurality of relay stations configured to receive and relay wireless communication signals from at least one base station; Dividing the relay stations into first and second groups based at least on potential interference between at least some of the relay stations; Dividing the service period of at least one antenna of the at least one base station into multiple phases; And (1) controlling at least one of the signal transmission power of at least one antenna of the at least one base station and (2) the signal communication timing of the at least one antenna to be directed to or from the relay station of the first group in the first phase. Allowing communication of the signal, and allowing the second group of relay stations to communicate the signal independently from signals directed to or caused by the first group of relay stations during at least a portion of the first phase. It features. The relay stations of the first group are configured to receive and relay a first group of radio communication signals from at least one base station, and the relay stations of the second group receive and relay a second group of radio communication signals from at least one base station. It is configured to. In some demonstrative embodiments, relay stations of the first group and relay stations of the second group may have overlap within the coverage area of the relay stations of the first group and the coverage areas of the relay stations of the second group.

If the layout of the base station and the relay station is different, all base stations and relay stations may still be idle in the frame structure for a predetermined time. Therefore, transmission efficiency may not be desirable. Therefore, a need exists for a system and method for multi-hop relay in a wireless communication system that can provide alternative implementations or applications.

The disclosed embodiments can be applied to various layouts of base stations, relay stations or both. For simplicity and illustrative purposes of the detailed description, the example embodiments described below are described using an environment similar to Manhattan. Embodiments may be practiced in any other environment in accordance with the same or similar concepts described below. In an environment similar to Manhattan or in some other environment, interference levels may be weakened by spatial separation, such as produced by the shadowing effect of surrounding buildings, and the grouping of the relay station may be changed accordingly. Can be.

7 is an exemplary diagram illustrating the layout of a base station 805 and a plurality of relay stations 801-804 in a Manhattan-like environment consistent with the particular embodiments disclosed. Referring to FIG. 7, the microcell may cover 690 * 690 square meters in one embodiment, and the base station 805 may be located at a crossroad. Four relay stations 801, 802, 803, and 804 may be located at a specific intersection located outside base station 805, that is, at four intersections just outside of where the base station 805 is located. As one example, relay stations 801 through 804 may be of a distance having a line of sight (LOS) of base station 805 and another distance having a non-line of sight (NLOS) of base station 805. May be placed at the intersection.

In one embodiment, the base station 805 includes four directional antennas for transmitting data to one or both of (1) users on or near the distance in four directions and (2) the relay stations 801 to 804. 4-sector antennas may be used. The relay stations 801 through 804 may use two directional antennas or two-sector antennas to transmit data to a user belonging to the NLOS (or outside the LOS) of the base station 805. Base stations 805 and relay stations 801 through 804 may provide services to all users in cell coverage area 811. In one embodiment, users in the LOS of base station 805 may have a single-hop link to base station 805, while users outside the LOS of base station 805 may be the same as relay stations 801 through 804. A multi-hop link may be established with the base station 805 through one or more relay stations.

8 is an exemplary flow diagram illustrating a scheduling method of a wireless multi-hop relay communication system consistent with certain disclosed embodiments. Referring to Fig. 8, after starting up the base stations 805 and the relay stations 801 to 804 in step S101, one or more of the relay stations 801 to 804 determines the level of interference from other relay stations and base stations in step S102. It can be measured. In some embodiments, the interference level or potential interference level may be obtained by observing or processing the data signal or the reference signal transmitted by the relay station and the base station. The data signal or reference signal may comprise a preamble having a preamble index, which may be used or may be used to measure signal strength of a wireless multi-hop relay communication system. Alternatively, the potential interference level may be a signal-to-interference-and-noise ratio (SINR), carrier-to-interference ratio of a data signal or a reference signal. can be measured by observing or determining factors such as -and-noise-ratio (CINR), and received signal strength indicator (RSSI).

In step S103, the relay stations 801 to 804 may report the measurement results back to the base station 805. The base station 805 may then divide the relay stations 801 through 804 into groups based on the results. Base station 805 may split base stations with interference that may interact with each other or potentially exceed certain thresholds and divide them into different groups. For example, relay stations 801 and 803 may be included in group A, while relay stations 802 and 804 may be included in group B. As a result, stations within a group may be less likely to interfere with each other when some or all of them transmit signals simultaneously. In another embodiment, if one transmitting target of the relay stations 801-804 is another relay station, and the target relay station cannot receive and transmit data at the same time, the two relay stations may be included in different groups. Furthermore, because the number of groups may be related to the number of phases in transmission scheduling, and thus may affect the utilization efficiency of the communication system, the number of groups may be kept as small as possible in some embodiments. Can be.

In step S104, the base station 805 may adjust the transmission schedule for them after the relay stations 801 to 804 are grouped. In one embodiment, the number of groups may be the number of phases within the service period for transmission scheduling. Thereafter, the base station 805, the relay stations 801 to 804, and the users can initiate communication with each other in step S105.

9A is an example functional block diagram illustrating a wireless communication system consistent with the particular embodiment disclosed. Referring to FIG. 9A, a wireless communication system may include two or more groups of relay stations and one or more base stations, that is, relay stations 921 (RS1) and 922 (RS2) included in group 1, and Relay stations 923 (RS3) and 924 (RS4) in group 2 and base station 920 may be included. The first group of relay stations (group 1) can be configured to receive and relay a first group of wireless communication signals, and the second group of relay stations (group 2) is configured to receive and relay a second group of wireless communication signals Can be. Relay stations in the first and second groups may be divided into groups based on one or more considerations, such as potential interference between stations in the same cell and potential interference from other serving stations in the same cell, such as using the same co-channel. Can be divided. A base station in a wireless communication system, such as base station 920, controls communications such as communication control device 920C, which may be directly or indirectly connected to one or more antennas, such as antenna 920A, and antenna 920A for signal communication. It may include a device. The base station 920 may be configured to communicate with a first group of relay stations and a second group of relay stations, and the communication control apparatus 920C may include signal transmission power of one or more antennas 920A and one or more antennas ( And control one or more transmission control parameters, such as the signal communication timing of 920A.

In some embodiments, the communication control device 920C may be configured to divide the service period of one or more antennas into two or more phases, and change the number of phases depending on the number of groups in the system. Can be. The communication control device 920C may allow transmission of signals directed to or caused by the first group of relay stations in the first phase. In addition, the communication control device 920C directs the second group of relay stations to or during the at least a portion of the first phase, independently of the signals directed to or caused by the first group of relay stations, one or more user devices, one or more. It may allow communication with more base stations, or both. In addition, the communication control device 920C permits (1) transmission of signals to or caused by the second group of relay stations in the second phase, and (2) during the at least a portion of the second phase of the first group of relay stations, The signal may be configured to allow communication of the signal, independent of the signal directed to or caused by the second group of relay stations. In addition, the communication control apparatus 920C may determine an order of providing a service to different relay station groups within the service period. The antenna (s) 920A of the base station 920 may be configured to have directivity and may be configured to provide services to relay stations in the directive or pointed area.

The relay stations RS1 to RS4 may be implemented in various ways. For example, one or more relay stations in the first and second groups may be arranged to have a virtual line of sight (LOS) of one or more base stations. Base stations (depending on their number), interference between base stations and other factors may also be divided into further groups, such as three or more groups. Relay stations are generally configured to provide service to user devices that are not located within the virtual line of sight of the base station (s) or to provide service to user devices, thereby improving link quality when communicating through relay station (s), It is configured to provide improved overall link spectral efficiency, or both, but is not necessarily forced to do so. In comparison, one or more of these qualities may be undesirable as desired when the user devices communicate directly with the base station (s) without passing through the relay station (s).

In one embodiment, in addition to the antenna 920A and the communication control device 920C, the base station 920 is configured to communicate with a first group of relay stations (group 1) and a second group of relay stations (group 2). 920T. In one embodiment, the relay stations in the first and second groups are divided into groups based at least on potential interference or interference between at least some of the relay stations.

In some embodiments, the wireless communication system may have three or more groups of relay stations. In the case of three groups, three groups of relay stations may be configured to receive and relay three groups of wireless communication signals. The third group of relay stations and the first and second groups of relay stations may have overlap within their coverage area. As mentioned above, different groups of relay stations may be divided into groups based on potential interference between some or all of the relay stations or based on other factors. In one embodiment, the communication control device (1) allows communication of signals to or from the third group of relay stations in the third phase; (2) and during at least a portion of the third phase, relay stations of one or both groups of the first and second groups, independently of the signals directed to or caused by the third group of relay stations, to signal at least one base station and It may be further configured to allow communication.

A method of wireless communication consistent with the system described above may be provided in one embodiment of the present invention. The method includes establishing communication between at least one base station and a plurality of relay stations configured to receive and relay wireless communication signals from the at least one base station; Dividing the relay stations into first and second groups based at least on potential interference between at least some of the relay stations; Dividing the service period of at least one antenna of the at least one base station into multiple phases; And (1) controlling at least one of the signal transmission power of at least one antenna of the at least one base station and (2) the signal communication timing of the at least one antenna to be directed to or from the relay station of the first group in the first phase. Allowing communication of the signal. This control method may also allow the second group of relay stations to communicate the signal independently from signals directed to or caused by the first group of relay stations during at least a portion of the first phase.

In one embodiment of the invention, dividing the relay station comprises at least one of (1) potential interference between at least some of the relay stations in the same cell and (2) potential interference from other serving stations in at least one co-channel cell. It can be done based on one. In another embodiment of the present invention, the control operation controls communication of one or both of the aforementioned factors, thereby (1) allowing communication of signals to or from a second group of relay stations in a second phase, and (2 ) Allowing the first group of relay stations to communicate the signal independently from signals directed to or caused by the second group of relay stations during at least a portion of the second phase. Similarly, the control operation permits communication of signals to or from the third group of relay stations in the third phase by controlling one or both of the factors described above, and (2) Further allowing at least one of the first and second group of relay stations to communicate with the at least one base station independently from the signals directed to or caused by the third group of relay stations during at least some of the signals. Can be.

In a further embodiment of the present invention, if the number of groups is N, the service period of the total transmission scheduling may be divided into N phases, each phase having one or more downlink transmissions, one or more uplink transmissions, Or both of them. The service period may be the length of the frame, and the frame may be divided into N phases. In addition, the service period may be a length of a plurality of frames, and the frames may be divided into N phases as a group. Downlink and uplink transmissions during various phases within a frame may be aligned according to the definition of the frame. For example, various phases or downlink or uplink transmissions within each phase may be alternated, or downlink transmissions of the various phases may be aligned prior to uplink transmissions. Using the disclosure herein, those skilled in the art will appreciate that various devices for downlink and uplink transmission may be implemented depending on the application and other considerations. In one embodiment, relay stations 801 through 804 may be divided into two groups, so that the service period may be divided into two phases.

9B is an exemplary diagram illustrating a first phase of transmission scheduling for uplink transmissions and downlink transmissions consistent with the particular embodiments disclosed. Referring to FIG. 9B, during a first phase, the base station 905 may (1) be located in the same direction as the relay stations 901 and 903 both grouped into group A and (2) group A in the same direction. A service may be provided to one or both of the users in LOS 906 and 907 of. Base station 905 may provide service to Group A, for example, via downlink transmissions, uplink transmitters, or both.

In one embodiment, downlink transmission means that the base station 905 transmits data while the users in the LOS 906 and 907 of the base station 905 in the direction of group A and the relay stations 901 and 903 in group A. If you send to. During the same phase, the relay station 902 in the second group (group B) sends data received from the base station 905 during the previous phase to the user in the NLOS of the base station 905 and the users in the LOS 908 and 909 of the group B. The relay station 904 in group B may relay data received from the base station 905 during the previous phase to the user in the NLOS of the base station 905 and the user in the LOS 910 and 911 of the group B. . Further, depending on the application, the base station 905 may provide appropriate power control at relatively low transmit power during the first phase to the user in the service area 912 and 913 around the base station 905 and the user in the direction of group B. Can be configured to provide services. Lower transmission power can reduce interference in relay stations 901-904 caused by base station 905 to a level below an acceptable threshold.

In one embodiment of the present invention, uplink transmission means that base station 905 receives data, but receives data from relay stations 901 and 903 in group A, and that of base station 905 in the direction of group A. Represents a case where users in LOS 906 and 907 transmit data. During the same phase, relay station 902 in group B may receive uplink data from users in areas 908 and 909, and relay station 904 in group B may be up from users in areas 910 and 911. Link data can be received. Furthermore, depending on the application, users in the service areas 912 and 913 around the base station 905 and users in the direction of group B may be allowed to transmit uplink data to the base station 905 during the first phase. .

10 is an exemplary diagram illustrating a second phase of transmission scheduling for uplink transmission and downlink transmission in a single cell consistent with the particular embodiment disclosed. Referring to FIG. 10, during the second phase, base station 905 may provide services to users in LOS 1006 and 1007 of base station 905 in the direction of Group B and Group B. Base station 905 may provide service to Group B, for example, via downlink transmission and / or uplink transmission.

In one embodiment, downlink transmission during the second phase means that the base station 905 sends data to the relay stations 902 and 904 in group B and the users in the LOS 1006 and 1007 of the base station 905 in the direction of group B. FIG. It means when sending to them. During the same phase, relay stations 901 and 903 in group A individually transmit data received from base station 905 during the previous phase and the user in group NLOS of base station 905 and LOS of group A (1008 to 1009 and 1010 to 1011). Can relay to users within Further, base station 905 provides services with appropriate power control at relatively low transmit power during the second phase to users in service areas 1012 and 1013 around base station 905 and users in the direction of group A. It can be configured to.

In one embodiment of the present invention, uplink transmission during the second phase means that the users in the LOS 1006 and 1007 of the relay stations 902 and 904 in Group B and the base station 905 in the direction of Group B receive data. The case where it can transmit to the base station 905 is shown. During the same phase, relay station 901 in group A may receive uplink data from users in areas 1008 and 1009, and relay station 903 in group A may be up from users in areas 1010 and 1011. Link data can be received. Furthermore, users in areas 1012 and 1013 may be allowed to transmit uplink data to base station 905 during the second phase.

FIG. 11 is an exemplary diagram illustrating a first phase of transmission scheduling for uplink transmissions and downlink transmissions between adjacent cells consistent with certain disclosed embodiments. Referring to FIG. 11, in a multi-cell structure, the service order of transmission scheduling of two adjacent cells may be changed based on one or more factors such as interference between cells and signal quality of a user present at a cell boundary. . Cells adjacent to cell A (having coverage area 1106) in four directions are cell B (having coverage area 1116), cell C (having coverage area 1126), and cell D (coverage area 1136). ), And cell E (having a coverage area 1146). Base stations 1115 and relay stations 1111 to 1114 may be located within the coverage area 1116 of Cell B; Base stations 1125 and relay stations 1121 through 1124 may be located within the coverage area 1126 of cell C; Base stations 1135 and relay stations 1131 to 1134 may be located within the coverage area 1136 of cell D; Base stations 1145 and relay stations 1141 to 1144 may be located within the coverage area 1146 of cell E. In one embodiment, the service order of cells B to E may be the same. Accordingly, for convenience of explanation, only cell B is described below by way of example below.

Within the coverage area 1106 of cell A, the base station 1105 is the LOS of the base station 1105 in the direction of the relay stations 1101 and 1103 in group A and group A (such as a group performing single cell transmission scheduling). When providing services to users within, neighboring base stations in four directions (i.e., base station 1115 in coverage area 1116 of cell B) are relay stations 1112 and 1114 in group B and group B (single cell). Service may be provided to users in the LOS of base station 1115 in the direction of a group (such as a group performing transmission scheduling). In addition, relay stations 1102 and 1104 in group B within coverage area 1106 of cell A and relay stations 1111 and 1113 in group A within coverage area 1116 of cell B are responsible for data transmission to provide services to users. The same data transmission can be performed. In another embodiment, relay stations 1105 and 1115 may transmit data to users in areas 1107-1108 and 1117-1118 individually at relatively low transmit power.

12 is an exemplary diagram illustrating a second phase of transmission scheduling for uplink transmissions and downlink transmissions between adjacent cells consistent with certain disclosed embodiments. Referring to FIG. 12, within coverage area 1106 of cell A, base station 1105 provides services to users in the LOS of relay stations 1102 and 1104 in group B and base station 1105 in the direction of group B. In providing, neighboring base stations in four directions (i.e., base station 1115 in cell B's coverage area 1116) are connected to relay stations 1111 and 1113 in group A and base station 1115 in the direction of group A. It can provide services to users in the LOS. In addition, relay stations 1101 and 1103 in group A in coverage area 1106 of cell A and relay stations 1112 and 1114 in group B in coverage area 1116 of cell B are responsible for data transmission to provide services to users. The same data transmission can be performed. In another embodiment, relay stations 1105 and 1115 may transmit data to users in regions 1207-1208 and 1217-1218 separately at relatively low transmit power.

FIG. 13 is an exemplary diagram illustrating operations of transmission scheduling during various phases of a single cell consistent with the particular embodiment disclosed. Referring to FIG. 13 and also to FIGS. 9 and 10, the operations S1311 and S1312 during the first phase S1310 of the single cell transmission scheduling are performed by the base station 905 using the relay stations 901 and 903 of Group A and Providing services to users in areas 906 and 907. During the same phase, operations S1313 and S1314 during the first phase S1310 of single cell transmission scheduling indicate that group B relay stations 902 and 904 are individually directed to users in the areas 908-909 and 910-911. It may include an operation of providing a service. Furthermore, operations S1315 and S1316 during the first phase S1310 of single cell transmission scheduling may include the operation of the base station providing services to users in the regions 912 and 913.

Operations S1323 and S1324 during the second phase S1320 of single cell transmission scheduling allow the base station 905 to service users in group B's relay stations 902 and 904 and in areas 1006 and 1007. May include an action. During the same phase, operations S1321 and S1322 of single cell transmission scheduling perform operations in which group B relay stations 901 and 903 individually service users in the areas 1008-1009 and 1010-1011. It may include. Furthermore, operations S1325 and S1326 during the second phase S1320 of single cell transmission scheduling may include an operation where the base station 905 provides services to users in the regions 1012 and 1013.

In a multi-cell structure, the service order of transmission scheduling in the frame structure of two adjacent cells may be changed based on one or more considerations such as intercell interference and signal quality of the user located at the cell boundary.

Table 1 shows exemplary differences between one embodiment of the present invention and the prior art in a wireless communication system. In Table 1, "frequency reuse factor" refers to the ratio of (1) the available frequency of a single cell to (2) the available frequency of the system. In one embodiment, since the base station is only one station connected to a backhaul network in the cell, an "effective frame" may refer to the number of frames that the base station receives and transmits during the service period. "Capacity gain" may be obtained based on the "frequency reuse factor" and "effective frame" factors. One embodiment of the present invention is compared to the second setup under the configuration in which all serving stations in the WINNER design described above include omnidirectional antennas having the same coverage area. Design 1 illustrates the case where the base station does not provide service to users around the base station at relatively low transmit power, and design 2 uses the appropriate power control to service the user around the base station at relatively low transmit power. The case of providing is illustrated.

Frequency reuse factor Valid frame Capacity gain
Second set up in the design of WINNER with omnidirectional antennas in all serving stations


1/2

2/3

One
Design of one embodiment 1

2
6
Another embodiment design 2
One
4
12

In a second setup under the WINNER design, data may be transmitted between adjacent cells at different frequencies to prevent intercell interference. Accordingly, the "frequency reuse factor" is 1/2. In this design, six phases are required to complete the downlink transmission or the uplink transmission. The actual number of frames transmitted by the base station is 4, thus the "effective frame" is 2/3 (= 4/6).

Under design 1, data can be transmitted at the same frequency between adjacent cells. Thus, the "frequency reuse factor" is one. During two phases of a full downlink transmission, the base station can transmit four frames, with the result that the "effective frame" is two. Uplink transmission is similar to downlink transmission. Furthermore, considering that the "capacitance gain" of the prior art is 1, design 1 may have two or more factors when using the frequency spectrum. The "effective frame" of design 1 may be three times the prior art, and consequently the "capacitance gain" may be "6".

Under design 2, the “frequency reuse factor” is 1 since data can be transmitted at the same frequency between adjacent cells. During two phases of full downlink transmission, the base station can transmit eight frames, with the result that the "effective frame" is four. Uplink transmission is similar to downlink transmission. Furthermore, considering that the "capacitance gain" of the prior art is 1, design 2 may have two or more factors when using the frequency spectrum. The "effective frame" of the first design of the present invention may be six times the prior art, and consequently the "capacitance gain" may be "12".

In the above embodiment, the service areas of the base station and the relay station in the wireless multi-hop relay communication system may be divided into a plurality of areas because of the surrounding shadowing effect. The strength of the interference level can be observed or determined by one or more relay stations and provided to the base station. Since the base station can divide the relay station into different groups based on the corresponding information, the base station can sequentially provide services to the different groups. Because of the desired isolation from interfering signals due to shadowing effects or other reasons, the same radio resource can be reused and scheduled for different relay stations, resulting in a system improvement without increasing signaling interference. In a multi-cell structure, universal frequency reuse can be obtained by changing the service order or transmission scheduling of the neighbor cell. Through changes in the mechanism of grouping and transmission scheduling, interference within a single cell and interference between adjacent cells can be prevented or reduced, and high spectral efficiency can be obtained through aggressive radio frequency reuse. Furthermore, in the transmission scheduling structure provided in the embodiments of the present invention, the base station can transmit data during various phases, and the effective cell / system capacity can be significantly improved.

If the relay station and one or more base stations are considered together in an established environment, one or more of the interference detection, relay group grouping and scheduling mechanisms described above may be implemented to determine the transmission sequence between the base station and the relay station. If the base station has already been set up in a given environment and relay stations are added, one or more of the interference detection, relay group grouping and scheduling mechanisms described above may be implemented, thereby allowing for original cell planning such as the location (s) of the base station (s). It may be possible to determine the transmission or transmission between all devices without modification. The disclosed embodiments can be implemented within any network architecture using wireless technology, protocols or standards. In this way, the disclosed embodiments can allow the system to use resources more efficiently. In particular, the disclosed embodiments can increase the efficiency of the use of the wireless communication frequency spectrum, or reduce undesirable interference.

It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments disclosed herein. The embodiments disclosed herein are merely exemplary, and the technical scope of the disclosed embodiments is provided by using the appended claims. In addition, in describing embodiments of the present invention, the present specification has provided exemplary methods or processes using steps in a particular order. However, to the extent that the methods and processes do not rely on the specific order of steps described herein, the described method or process is not limited to the specific sequence of steps described.

The invention can be applied to various layouts of base stations, relay stations or both.

1 is a diagram illustrating the layout of a base station and a plurality of relay stations in a single cell in a Manhattan-like environment in a prior art communication system.

FIG. 2 is a diagram illustrating transmission scheduling of a frame structure that may be applied to the layout shown in FIG. 1 in the prior art.

FIG. 3 is a diagram illustrating the layout of a base station and a relay station in a multi-cell structure of the Manhattan-like environment shown in FIG. 2 in the prior art.

FIG. 4 is a diagram illustrating transmission scheduling for a frame structure applicable to the layout shown in FIG. 3 within a multi-cell structure in a Manhattan-like environment in the prior art.

FIG. 5 is a diagram illustrating a second layout of four relay stations with base stations and omnidirectional antennas in a Manhattan-like environment in the prior art.

FIG. 6 is a diagram illustrating transmission scheduling for a frame structure that may be applied to the layout shown in FIG. 5 in the prior art.

FIG. 7 is an exemplary diagram illustrating the layout of a base station and a plurality of relay stations in a Manhattan-like environment consistent with the specific embodiments disclosed.

8 is an exemplary flow diagram illustrating a scheduling method of a wireless multi-hop relay communication system consistent with certain disclosed embodiments.

9A is an example functional block diagram illustrating a wireless communication system consistent with the particular embodiment disclosed.

9B is an exemplary diagram illustrating a first phase of transmission scheduling for uplink transmissions and downlink transmissions consistent with the particular embodiments disclosed.

10 is an exemplary diagram illustrating a second phase of transmission scheduling for uplink transmission and downlink transmission in a single cell consistent with the particular embodiment disclosed.

FIG. 11 is an exemplary diagram illustrating a first phase of transmission scheduling for uplink transmissions and downlink transmissions between adjacent cells consistent with certain disclosed embodiments.

12 is an exemplary diagram illustrating a second phase of transmission scheduling for uplink transmissions and downlink transmissions between adjacent cells consistent with certain disclosed embodiments.

FIG. 13 is an exemplary diagram illustrating operations of transmission scheduling during various phases of a single cell consistent with the particular embodiment disclosed.

Claims (20)

In a wireless communication system, A first group of relay stations configured to receive and relay a first group of wireless communication signals; A second group of relay stations configured to receive and relay a second group of wireless communication signals; And At least one base station configured to communicate with the relay stations of the first group and the relay stations of the second group, Relay stations in the first and second groups may be divided into groups based at least on potential interference between relay stations in the same cell and from other serving stations in at least one co-channel cell. Divided, at least one base station, At least one antenna for signal communication; And A communication control device connected to the at least one antenna, the communication control device being configured to control at least one of (1) signal transmission power of at least one antenna and (2) signal communication timing of at least one antenna, The communication control device, Divide the service period of the at least one antenna into at least two phases, permit communication of signals to or from the first group of relay stations in a first phase, and the first Configure the second group of relay stations to communicate with at least one user device and at least one base station independently from signals directed to or caused by the first group of relay stations during at least a portion of the phase Wireless communication system, characterized in that. The method of claim 1, At least one of the relay stations in the first and second groups is arranged to have a virtual line of sight of one of at least one base station. The method of claim 1, At least one of the relay stations in the first and second groups is configured to provide a service to a user device that is not located within the virtual line of sight of the at least one base station. The method of claim 1, At least one of the relay stations in the first and second groups has at least one of (1) improved link quality when communicating via the relay station and (2) improved overall link spectral efficiency when communicating via the relay station. And provide a service to a user device. The method of claim 1, And the transmission control apparatus of the at least one base station determines the order of providing a service to different groups of relay stations within the service period. The method of claim 1, The at least one antenna is directional and is configured to provide services to relay stations within a predetermined directional area. According to claim 1, The communication control device, Permit communication of signals to or from the second group of relay stations in a second phase, and independently from signals directed to or caused by relay stations of the second group during at least a portion of the second phase; And further configured to allow the first group of relay stations to communicate the signal. In a wireless communication system, At least one base station configured to communicate with at least one user device via at least one relay station, wherein the at least one base station comprises: At least one antenna for signal communication; A transceiver connected to the at least one antenna, the transceiver comprising a first group of relay stations and a second group of wireless communication signals configured to receive and relay a first group of wireless communication signals from the at least one base station And communicate with a second group of relay stations configured to receive and relay from the at least one base station, wherein the relay stations in the first and second group are grouped based at least on potential interference between at least some of the relay stations. Transmitting and receiving device divided into two; And A communication control device coupled to the at least one antenna and the transceiver, and configured to control at least one of (1) signal transmission power of at least one antenna and (2) signal communication timing of the at least one antenna; The communication control device, Divide the service period of the at least one antenna into multiple phases, permit communication of signals to or from the first group of relay stations in a first phase, and during the at least a portion of the first phase And allow the second group of relay stations to communicate the signal independently from signals directed to or caused by the group of relay stations. The method of claim 8, Relay stations in the first and second groups are based on at least one of (1) potential interference between at least some of the relay stations in the same cell and (2) potential interference from other serving stations in at least one co-channel cell. And divided into groups. According to claim 8, The communication control device, Permit communication of signals to or from the second group of relay stations in a second phase, and independently from signals directed to or caused by relay stations of the second group during at least a portion of the second phase; Further configured to allow a first group of relay stations to communicate with the at least one base station. The method of claim 8, Further comprising a third group of relay stations configured to receive and relay a third group of a wireless communication system, The relay stations of the third group and the relay stations of the second group have overlapping coverage areas of the relay stations of the third group and coverage areas of the relay stations of the second group, The third and second group of relay stations are divided into groups based at least on potential interference between at least some of the relay stations, and the communication control apparatus may further include: Permit communication of signals to or from the third group of relay stations in a third phase, and independently from signals directed to or caused by the third group of relay stations during at least a portion of the third phase; And further configured to allow a second group of relay stations to communicate the signal. The method of claim 8, And at least one of the relay stations in the first and second groups is arranged to have a virtual line of sight of one of at least one base station. The method of claim 8, At least one of the relay stations in the first and second groups is configured to provide a service to a user device that is not located within the virtual line of sight of the at least one base station. The method of claim 8, At least one of the relay stations in the first and second groups has at least one of (1) improved link quality when communicating via the relay station and (2) improved overall link spectral efficiency when communicating via the relay station. And provide a service to the user device. The method of claim 8, And the transmission control apparatus of the at least one base station determines the order of providing a service to different groups of relay stations within the service period. The method of claim 8, The at least one antenna is directional and is configured to provide services to relay stations within a given directional area. In the wireless communication method, Establishing communications between at least one base station and a plurality of relay stations configured to receive and relay wireless communication signals from the at least one base station; Dividing the relay stations into first and second groups based at least on potential interference between at least some of the relay stations, the relay stations of the first group receiving a first group of wireless communication signals from the at least one base station; Configured to receive and relay, the second group of relay stations configured to receive and relay a second group of wireless communication signals from the at least one base station, the first group of relay stations and the second group of relay stations And having overlapping coverage areas of the relay stations of the first group and coverage areas of the relay stations of the second group; Dividing the service period of at least one antenna of the at least one base station into multiple phases; And Controlling at least one of (1) the signal transmission power of at least one antenna of the at least one base station and (2) the signal communication timing of the at least one antenna to be directed to or from the relay station of the first group in a first phase Permitting communication of a signal of and allowing the second group of relay stations to communicate the signal independently from signals directed to or caused by the relay stations of the first group during at least a portion of the first phase. Wireless communication method comprising a. 18. The method of claim 17, wherein dividing the relay stations comprises: Relay stations in the first and second groups are based on at least one of (1) potential interference between at least some of the relay stations in the same cell and (2) potential interference from other serving stations in at least one co-channel cell. And dividing the data into groups. The method of claim 17, Controlling at least one of (1) the signal transmission power and (2) the signal communication timing to permit communication of signals to or from the second group of relay stations in a second phase, and at least of the second phase Allowing for some time the relay stations of the first group to communicate the signals independently from signals directed to or caused by the relay groups of the second group. The method of claim 17, Controlling at least one of (1) the signal transmission power and (2) the signal communication timing to permit communication of signals to or from a third group of relay stations in a third phase, and at least a portion of the third phase Allowing at least one of the first and second group of relay stations to communicate with the at least one base station independently from signals directed to or caused by the third group of relay stations during the process. Wireless communication method, characterized in that.

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