PATENT DOCUMENT

Publication Number: US-8554232-B2
Application Number: US-47871906-A
Country: US
Kind Code: B2

Title: Method and system for a wireless multi-hop relay network

Abstract:
A Point to Multipoint (PMP) multi-hop relay network includes a base station, one or more relay stations and one or more subscriber stations. Active service flows in a PMP multi-hop relay network have a 16-bit connection identifier (CID). A CID defines the connection that a packet is servicing. Before traffic can be transmitted, the path through the network, and the association of CIDs with respective hops needs to be established. The CID mapping relationship from the ingress air link to the egress air link at each relay station is first set up, which is then followed by a traffic phase where the CID mapping relationship is used to route traffic from a base station to a subscriber station.

Claims:
The invention claimed is: 
     
       1. A method for routing messages in a point-to-multipoint (PMP) wireless multi-hop relay network comprising a base station, at least one relay station, and a subscriber station, the method comprising:
 a. the at least one relay station receiving a signalling message containing a path list from the base station of the PMP wireless multi-hop relay network, and an initial connection identifier (CID) for a connection between the base station and one of the at least one relay stations; 
 b. the at least one relay station of the PMP wireless multi-hop relay network receiving the signalling message and replacing the CID contained in said signaling message with a new CID and forwarding the signalling message with the new CID, and 
 c. wherein step b. is repeated by one or more additional relay stations until the subscriber station is reached. 
 
     
     
       2. The method of  claim 1  wherein the path list has a starting point and an ending point, the starting point of the path list being a node identifier for the base station and the ending point of the path list being a node identifier for the subscriber station. 
     
     
       3. The method of  claim 2  wherein the path list is a set of node identifiers for all nodes between the base station and the subscriber station. 
     
     
       4. The method of  claim 1  wherein the path list is stored in a Medium Access Control (MAC) sub-header. 
     
     
       5. The method of  claim 1  wherein the initial CID and the new CID are tunnel CIDs. 
     
     
       6. The method of  claim 1  wherein the initial CID and the new CID are transport CIDs. 
     
     
       7. The method of  claim 1  wherein the initial CID is stored in a Dynamic Service (DSx) message. 
     
     
       8. The method of  claim 7  wherein the DSx message is a Dynamic Service Addition (DSA) message. 
     
     
       9. The method of  claim 1  further comprising:
 the at least one relay station creating an entry in a CID mapping table, the CID mapping table containing entries for each CID received in a signalling message, and for each new CID replaced. 
 
     
     
       10. The method of  claim 1 , wherein the method is applied to a WiMAX wireless network. 
     
     
       11. The method of  claim 1  further comprising,
 d. the at least one relay station receiving a frame containing a DL MAP and at least one DL Burst, the DL MAP containing a CID stack for a connection between the base station and one of the at least one relay stations; 
 e. the at least one relay station retrieving a new CID stack from a CID mapping table, and replacing the CID stack contained in said DL MAP with the new CID stack and forwarding the frame with the new CID stack, and 
 f. wherein step e. is repeated by the one or more additional relay stations until the subscriber station is reached. 
 
     
     
       12. The method of  claim 1  further comprising,
 d. the at least one relay station receiving a frame containing a DL MAP and at least one DL burst, the DL burst containing one or more Medium Access Control (MAC) messages but not containing a CID stack, each of the one or more MAC messages containing an initial transport CID for a connection between the base station and one of the at least one relay stations; 
 e. the at least one relay station replacing the transport CID contained in at least one of said MAC messages with a new transport CID and forwarding the MAC message with the new transport CID, and 
 f. wherein step e. is repeated by the one or more additional relay stations until the subscriber station is reached. 
 
     
     
       13. The method of  claim 1  further comprising,
 d. the at least one relay station receiving a MAC PDU containing a transport CID provided by the subscriber station; 
 e. the at least one relay station creating a relay sub-header for said MAC PDU, the relay sub-header containing an initial tunnel CID; 
 f. wherein one of the one or more additional relay stations is configured to receive the MAC PDU and relay sub-header and replace the tunnel CID contained in said relay sub-header with a new tunnel CID and forward the MAC PDU and relay sub-header with the new tunnel CID, and 
 g. wherein step f. is repeated by until the subscriber station is reached. 
 
     
     
       14. A relay station in a point-to-multipoint (PMP) wireless multi-hop relay network, the relay station comprising:
 a memory storing a CID mapping table; 
 a CID distribution controller, configured to:
 receive a wirelessly transmitted signaling message sent from another station in the PMP wireless multi-hop relay network, the signalling message containing an ingress CID and a path list, 
 allocate a corresponding egress CID based on the path list, and 
 create an entry in said CID mapping table for each of the ingress CID and its corresponding egress CID; and 
 
 a CID swapper, configured to replace the ingress CID in a MAC PDU with the egress CID. 
 
     
     
       15. The relay station of  claim 14  wherein the ingress CID and the egress CID are tunnel CIDs. 
     
     
       16. The relay station of  claim 14  wherein the ingress CID and the egress CID are transport CIDs. 
     
     
       17. The relay station of  claim 14  wherein the network is a WIMAX network. 
     
     
       18. The relay station of  claim 14  wherein the path list is a set of node identifiers for all nodes between a base station and a subscriber station. 
     
     
       19. The relay station of  claim 14  wherein the path list is stored in a Medium Access Control (MAC) sub-header. 
     
     
       20. The relay station of  claim 19  wherein the DSx message is a Dynamic Service Addition (DSA) message.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/709,052 filed on Aug. 17, 2005, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to wireless signalling protocols and systems. 
     BACKGROUND OF THE INVENTION 
     WiMAX is described in the IEEE 802.16 Wireless Metropolitan Area Network (MAN) standard. WiMAX allows for high-speed wireless data transmissions over long distances. 
     The core components of an 802.16 network are base stations (BS) and subscriber stations ((SS), sometimes referred to as mobile stations (MS)). The IEEE 802.16-2005 standard (formerly named but still known as IEEE 802.16e or Mobile WiMAX) is designed to support Point-to-Multipoint (PMP). 
     In PMP mode, the BS and one or more SS&#39;s are organized into a cellular-like structure. This type of network requires that all SS be within the transmission range and clear line of sight of the BS which uses an omnidirectional antenna. The BS controls activity within the cell, including access to the network by a SS, and allocations to achieve quality of service (QoS).  FIG. 1A  is a pictorial view of a PMP network in which BS  50  is in PMP communication with SS  52 , SS  53 , SS  54  and SS  55 .  FIG. 1B  is a schematic diagram of a very simple PMP network in which BS  12  is in point-to-multipoint communication with both SS  14  and SS  16 . 
     But in cellular-like PMP mode, there are many limitations such as cell transmission coverage, frequency re-use, power consumption, system capacity and performance beyond the boundaries of the BS coverage area. These limitations would cause signal degradation such as path loss, shadowing, and increase the complexity for handover in a large scale and high-speed mobility environment. 
     SUMMARY OF THE INVENTION 
     According to a broad aspect of the invention, there is provided a method for routing messages in a wireless multi-hop relay network comprising a base station, at least one relay station, and a subscriber station, the method comprising: a. the base station sending a signalling message containing a path list, and an initial connection identifier (CID) for a connection between the base station and one of the at least one relay stations; b. one of the at least one relay stations receiving the signalling message and replacing the CID contained in said signalling message with a new CID and forwarding the signalling message with the new CID, and c. repeating step b. until the subscriber station is reached. 
     In some embodiments, the path list is a set of node identifiers for all nodes between the base station and the subscriber station. In some embodiments the path list is stored in a Medium Access Control (MAC) sub-header and the MAC sub-header is a relay sub-header. 
     In some embodiments, the CID is stored in a Dynamic Service (DSx) message, and the DSx message is a Dynamic Service Addition (DSA) message. 
     In some embodiments the initial CID and the new CID are transport CIDs. In some embodiments, the initial CID and the new CID are tunnel CIDs. 
     In some embodiments, each of the at least one relay stations creating an entry in a CID mapping table, the CID mapping table containing entries for each CID received in a signalling message, and for each new CID replaced. 
     In some embodiments, the method is applied to a WiMAX wireless network. 
     In some embodiments, the method further comprises, d. the base station sending a frame containing a DL MAP and at least one DL Burst, the DL MAP containing a CID stack for a connection between the base station and one of the at least one relay stations; e. one of the at least one relay stations receiving the frame and replacing the CID stack contained in said DL MAP with a new CID stack and forwarding the frame with the new CID stack, and f. repeating step e. until the subscriber station is reached. 
     In some embodiments, the method further comprises: d. the base station sending a frame containing a DL MAP and at least one DL burst, the DL burst containing one or more Medium Access Control (MAC) messages but not containing a CID stack, each of the one or more MAC messages containing an initial transport CID for a connection between the base station and one of the at least one relay stations; e. one of the at least one relay stations receiving the one or more MAC messages and replacing the transport CID contained in at least one of said MAC messages with a new transport CID and forwarding the MAC message with the new transport CID, and f. repeating step e. until the subscriber station is reached. 
     A relay station in a wireless multi-hop relay network comprising: a CID mapping table; a CID distribution controller for receiving a signalling message sent from another station, the signalling message containing an ingress CID and a path list, the CID distribution controller adapted to allocate a corresponding egress CID based on the path list, and for creating an entry in said CID mapping table for each of the ingress CID and its corresponding egress CID; and a CID swapper for replacing the ingress CID in the signalling message with the egress CID. 
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described with reference to the attached drawings in which: 
         FIG. 1A  is a pictorial diagram of a point-to-multi-point (PMP) network; 
         FIG. 1B  is a schematic diagram of a very simple PMP network; 
         FIG. 2  is a schematic diagram of a multi-hop relay network according to an embodiment of the invention; 
         FIG. 3  is a schematic diagram of a frame used for Down link (DL) and Up link (UL) transmission in accordance with some embodiments of the invention; 
         FIG. 4A  is a schematic diagram of a Medium Access Control (MAC) header and relay sub-header used during the messaging setup phase of some embodiments of the invention; 
         FIG. 4B  is a schematic diagram of a Medium Access Control (MAC) header and relay sub-header used during the traffic phase of some embodiments of the invention; 
         FIG. 5  is a schematic diagram of control/data plane decoupling for a relay station used during the messaging setup phase in accordance with some embodiments of the invention; 
         FIG. 6  is a schematic diagram illustrating MAC layer CID processing for multi-hop relay; 
         FIG. 7  is a schematic diagram of a multi-level relay network illustrating an embodiment of the messaging setup phase of the invention; 
         FIG. 8A  is a schematic diagram of an OFDMA frame as received by a relay station during the traffic phase in accordance with some embodiments of the invention; 
         FIG. 8B  is a schematic diagram of an OFDMA frame after CID swapping during the traffic phase in accordance with some embodiments of the invention; 
         FIG. 9A  is a schematic diagram of a multi-level relay network illustrating in the traffic phase in accordance with some embodiments of the invention where there is no tunnel CID; 
         FIG. 9B  is a schematic diagram of a multi-level relay network illustrating in the traffic phase in accordance with some embodiments of the invention where there is a tunnel CID; and 
         FIG. 10  is a signalling flow diagram illustrating control/data message flow according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A wireless multi-hop relay access network is described herein. In a multi-hop relay access network, relay stations (RS&#39;s) are introduced for fixed, nomadic and mobile relay usage. The functional scope of a relay station can scale from being very simple such as an analog signal repeater, to a base station compliant fully functional device capable of radio resource scheduling, security authentication and connection management for mobile stations, in case a base station fails. 
       FIG. 2  is a schematic diagram of a very simple two-tier PMP relay network in which RS  62  and RS  63  supports PMP transmission to the attached SS and conducts relay functions between BS and SS. At the tree trunk level, BS  60  communicates with RS  62  and RS  63 . RS  62  in turn communicates with SS  65  and SS  66 . Similarly, RS  63  communicates with SS  67  and RS  68 . RS  68  communicates with SS  69 . 
     Through the use of a PMP multi-hop relay protocol, a payload can, for example, be delivered from BS  60  to SS  69  through RS  63  and RS  68 .  FIG. 2  is only one example of a PMP multi-hop relay network which can be used with the present invention. It is to be understood that the number of RS&#39;s and SS&#39;s in the network can vary from that shown in  FIG. 2 . The example of  FIG. 2  is a tree topology, and this is assumed for the details that follow. 
     In 802.16, all service flows have a 32-bit service flow identifier (SFID). For example, SFID  70  is used for a service flow between BS  60  and SS  69 . The SFID serves as the principal identifier in the subscriber station and the base station for the application service flow. Active service flows also have a 16-bit connection identifier (CID). A CID defines the connection between a BS and a SS that a packet is servicing. 
     In conventional one-hop PMP mode ( FIG. 1B ), both SFID and CID are global (end to end) and as such there is a one-to-one mapping between a SFID and a CID. Thus, in a one-hop transmission between a BS and a SS, there is a one-to-one correspondence between a CID and a SFID. In accordance with a PMP multi-hop relay mode provided by an embodiment of the present invention, a SFID (such as SFID  70 ) is still global but the CID may only have a local sense (i.e. it is used per-air-link for unidirectional point-to-point transmissions only to the next closest hop), or may have a global sense, depending on whether radio channel resources are allocated/scheduled locally (e.g., distributed allocation) or globally (e.g., centralized allocation), or the radio allocation is done in both way collectively (e.g., hybrid allocation). A transport CID represents per-flow-based air link connectivity, while a tunnel CID represents a “pipe” from a source node to a destination node, as described in more detail below. 
     This is shown in the example of  FIG. 2  where transport CID 1  represents a Connection Identification number for a service flow on link  33  between BS  60  and RS  63 . Transport CID 2  represents a Connection Identification number for the same service flow on link  57  between RS  63  and RS  68 . Transport CID 3  represents a transport Connection Identification number for the same service flow on link  51  between RS  68  and SS  69 . The set of transport CIDs of each air link from a BS to a SS forms an end-to-end switch path. 
     Using the transport CIDs, BS  60  and RS  63  may schedule their air links individually, and RS  63  may conduct traffic aggregation/distribution via a CID stack. For example, in the upstream direction, RS  63  can aggregate the uplink traffic received from SS  67  and RS  68  (with different CID) into one uplink traffic stream with tunnel CID 1  to BS  60 . In this example, tunnel CID, may have a global sense between aggregation RS  63  and BS  60  by crossing several air links. At aggregation RS  63 , multiple MAC Protocol Data Units (PDUs) with different transport CIDs can be encapsulated into a generic MAC header with a tunnel CID stack, and then to be transmitted upstream to BS  60 . Doing so will effectively promote efficiency of the uplink radio channel utilization. 
     In order to relay a traffic packet downstream from BS  60 , through RS  63 , to SS  68 , a facility is provided in order to receive a packet in respect of transport CID 1  at RS  63  and then to forward the packet in respect of transport CID 2 . Mechanisms for relaying traffic packets in this manner are detailed below. More generally, a facility is provided to relay traffic packets in this manner at any relay node. The procedure in RS  63  to change one CID (in this case, transport CID 1 ) to another CID (in this case, transport CID 2 ) is called “CID swapping”. 
     Before traffic can be transmitted using the various transport CIDs, the path through the network, and the association of transport CIDs with respective hops needs to be established. A specific example of a mechanism for identifying paths through a network for subsequent use in combination with the CID swapping approaches taught herein is “constraint based dynamic service signalling” as found in found in applicant&#39;s corresponding U.S. patent application Ser. No. 11/481,825 filed on Jul. 7, 2006. 
     The CID mapping relationship from the ingress air link to the egress air link can be set up by using existing 802.16 out of band dynamic service signalling messages with some minor modifications. Detailed examples are provided below. As such, end-to-end air paths can be provided for data transmission, QoS control, traffic engineering, and potential multi-service traffic over WiMAX transport. After a CID mapping relationship has been established, CID swapping will be applied to all the received application payload traffic. Whenever a service flow or a tunnel is terminated, the correspondent CID will be released for the future re-use. 
     CID Switch Path Setup using Modifications to 802.16 
     In some embodiments, the new PMP mode is provided by way of modifications to the 802.16 protocol that might be made to carry out PMP multi-hop relaying but it is to be understood that embodiments may be provided for other contexts. 
     In PMP mode, the 802.16 Medium Access Control (MAC) protocol is connection oriented. Upon entering the network, each SS creates one or more connections over which their data is transmitted to and from the BS. The MAC layer schedules the usage of the airlink resources and provides Quality of Service (QoS) differentiation. It performs link adaptation and Automatic Repeat Request (ARQ) functions to maintain target Bit Error Rates (BER) while maximizing the data throughput. The MAC layer also handles network entry for SS&#39;s that enter and leave the network, and it performs standard PDU creation tasks. 
       FIG. 3  shows a schematic diagram of an example frame structure for time division duplex (TDD) transmission used in conjunction with embodiments of the invention. Frame N, which is preceded by Frame N−1 and followed by Frame N+1, includes a downlink (DL) subframe  105  and an uplink (UL) subframe  108 . The DL subframe  105  includes a DL physical (PHY) PDU (protocol data unit)  110  that has a preamble  112 , a frame control header (FCH)  114  and multiple DL bursts  116 ,  118 ,  120 . A PDU is a data unit exchanged between peer entities. In some embodiments the multiple DL bursts  116 ,  118 ,  120  each have different modulation and coding. In other embodiments, some or all of the DL bursts have the same modulation and coding. A first DL burst  116  contains broadcast messages  124  to be broadcast to all RS and SS including DL MAP and UL MAP IEs (not shown). More specifically, the DL MAP is for broadcast to nodes (RS or SS) in communication with a given transmitter (BS or RS). The DL MAP contains a mapping of the time frequency resource to the content of individual receivers, typically through the use of CIDs. The DL MAP can be changed by relay stations as detailed below. 
     If the broadcast messages  124  do not occupy an entire allocated time duration for the first DL burst  116 , Medium Access Control (MAC) PDU messages  126  directed to one or more individual SS&#39;s may fill the remainder of the time slot. In some embodiments the broadcast messages may use more than a single DL burst. However, a shorter broadcast message means that more data can be transmitted in the frame. Subsequent DL bursts  118 ,  120  include multiple MAC PDU messages  128 ,  130  directed to one or more individual SS. In some embodiments the DL bursts include padding  132 . Each MAC PDU message contains a MAC header  134 . The MAC PDU message may also include a MAC message payload  136  and cyclic redundancy check (CRC)  138  as shown in  FIG. 3 . The CRC  138  is used for error detection. The broadcast messages  124  also contains a MAC header. 
     The UL subframe  108  shown in  FIG. 3  includes a contention slot  150  for initial ranging requests, which is a time duration for multiple SS communicating with the BS to contend for DL and/or UL resources. The UL subframe  108  also includes a contention slot  152  for bandwidth (BW) requests, which is a time duration for the multiple SS communicating with the BS to contend for additional UL resources. The UL subframe  108  also includes an UL PHY PDU  154 ,  156  that enables each source SS to communicate with the BS. Typically, the UL PHY PDU  154 ,  156  supports an UL burst  162  that is transmitted using a modulation and coding specific to the source SS. Each UL PHY PDU  154 ,  156  includes a preamble  160  and the UL burst  162 . The UL burst  162  includes multiple MAC PDU messages  164 , 166 . In some embodiments the UL burst  162  includes padding  168 . Each MAC PDU message  164 , 166  contains a MAC header  170 . The MAC PDU message  164 , 166  may also include a MAC message payload  172  and CRC  174 . Following the UL subframe  108  is a receive/transmit transition guard (RTG)  178 . Frames N−1 and N+1 have a similar composition. 
       FIG. 3  is an example frame that can be used in accordance with the invention. In some embodiments the frame may not include all the described components of  FIG. 3 , for example a frame may not include both described contention slots  150 ,  152 , or may include additional slots to allow contending for other reasons. Furthermore, a frame may have other additional guard slots such as a transmit/receive transition guard (TTG) located between the DL subframe  105  and UL subframe  108 . The frame of  FIG. 3  is consistent with the frame established for IEEE 802.16. However, the use of other frame structures may be considered within the scope of the invention if capable of supporting the PMP multi-hop relay protocols as described herein. 
     Frames enabling frequency division duplex (FDD) communication and combined TDD/FDD communication are also both considered to be within the scope of the invention. 
     As described above, MAC PDUs include MAC headers. MAC PDUs can be used to transmit data or MAC messages. There are two common forms of MAC header, a generic MAC header and a bandwidth request MAC header. There may also be one or more sub-headers defined for a MAC header. 
     The fields of a generic MAC header (see MAC header  134  in  FIG. 3 ) specially adapted to allow the setting up of paths through a network based on CID are illustrated in  FIG. 4A  and are collectively indicated at  400 . The numbers in brackets in each field indicate a number of bytes in the field. 
     Generic MAC header  400  includes a “Header Type (HT)” field  401 , an “Encryption Control (EC)” field  402 , a “Type” field  403 , an Extended Sub-header “ESF” field  404 , a “CRC indicator (CI)” field  405 , an “encryption key sequence (EKS)” field  406 , a “RSV” field  407 , a “Length (Len)” field  408 , a “CID” field  409  and a “Header Check Sequence (HCS)” field  410 . “HT” field  401  indicates the type of header. “Type” field  403  indicates sub-headers and special payload types present in the message payload. The “RSV” fields  404 ,  407  are reserved for variable use, which allows flexibility in the use of these fields. “Len” field  408  is the length in bytes of the MAC PDU including the MAC header and the CRC if present. 
     The CID field  409  in the generic MAC header  400  includes either a management CID for 802.16 system management messages or a transport CID for application traffic flow. “ESF” field  404  indicates extended sub-header format which relates to the existence of a sub-header group which can define up to 128 types of extended sub-headers. In accordance with one embodiment, sub-header  415  entitled “Relay sub-header” is defined which may optionally include a node ID list  420 . Node ID list  420  is a path list comprising a set of all the Node IDs along the selected path between a BS and a SS. 
     In 802.16, dynamic service flows may be created, changed, or deleted, which is accomplished through a series of MAC management messages known as dynamic service addition (DSA) for creating a new service flow, dynamic service change (DSC) for changing an existing flow, and dynamic service deletion (DSD) for deleting an existing service flow. Generically, these are referred to as DSx messages. 
     In DSx message body  450 , there is a field containing a transport CID associated with a given service flow (as defined in 802.16-2005). In multi-hop relay, this field  422  is extended to contain either a transport CID (per airlink based), or a tunnel CID (per subordinate tree section based), based on the type of destination node (RS or SS). If field  422  holds a transport CID, that CID would be associated with a given service flow at a path end point and at each air link interface. If field  422  holds a tunnel CID, that CID would be associated with a segmentation of relay path from BS to a RS/SS. With this approach, a transport CID in field  422  represents per-flow-based air link connectivity, while, as noted above, a tunnel CID in field  422  represents a “pipe” which is used for traffic engineering, traffic security and traffic aggregation purposes. 
     DSx message body  450  also contains SFID  322 . SFID  322  is used to identify a service flow between a BS and a SS. 
     In a particular implementation, MAC messages are either MAC management messages, or MAC payload messages. A DSx message with relay sub-header  415  containing a path list  420  is an example of a MAC management message that can be used to distribute CIDs along a given path. MAC management messages use path list  420  in relay sub-header  415  to build up an end-to-end CID path, while MAC payload message may use allocated transport CIDs in generic header  400  or tunnel CID  422  in relay sub-header  415  to navigate the data transmission. 
     Generally, in order to set up a path through the network, a DSx message containing an initial transport CID (or tunnel CID as the case may be) in field  422 , and containing path list  420  in relay sub-header  415  is generated and transmitted along the path on the basis of path list  420 . Each intermediate node receives the DSx message, and replaces the transport CID (or tunnel CID as the case may be) in field  422  with a transport CID (or tunnel CID as the case may be) for the next hop. Each intermediate node also establishes a mapping between the transport CID (or tunnel CID as the case may be) that was received and the transport CID (or tunnel CID as the case may be) that was transmitted. This mapping is used for forwarding traffic packets as detailed below. 
       FIG. 4B  is a schematic diagram of a Medium Access Control (MAC) header and relay sub-header used during the traffic phase of some embodiments of the invention. The description of elements already described in connection with  FIG. 4A  will not be repeated. 
     After the CID path has been established, the normal MAC payload PDU for the service flow can have transport CID  409  in its generic header and optionally have tunnel CID  472  and Quality of Service (QoS) priority field  474  in relay sub-header  415 . QoS priority field  474  is a parameter which provides QoS differentiation. Based on those CIDs, each RS along the give path would conduct CID swapping to relay the user traffic between BS and SS, and handle QoS processing based on QoS priority  474 . 
       FIGS. 4A and 4B  are two examples of a generic MAC header that those skilled in the art may be familiar with according to IEEE 802.15. In some embodiments there may be a greater or lesser number of fields in each of generic MAC header  400  and relay sub-header  415  than are shown in  FIGS. 4A and 4B . Furthermore, the header fields may have a different number of bytes than indicated in  FIGS. 4A and 4B . More generally, it is to be understood that a MAC header having a different layout but performing substantially the same task could be used in conjunction with relay sub-header  415 . 
     Decoupling of Data and Control 
     In some embodiments, having established the CID path as described above, the processing of traffic packets within the data plane is done without involvement of the control plane. The control plane and data plane may be implemented with separate processors/hardware/software or on a single processor/hardware software. 
       FIG. 5  is a schematic diagram of control/data plane decoupling for a relay station  504  used in accordance with some embodiments of the invention. The control plane functionality  531  is shown to comprise a CID distribution controller  528 . The data plane functionality  537  is comprised of CID swapper  530 , CID mapping table  535  containing egress CID  534  and its corresponding ingress CID  532 . The nature of the correspondence between egress CID  534  and ingress CID  532  will be described below. There is also a set of QOS buffers  536  which represents the queuing of packets according to QoS for delivery by the frame scheduler  538  by means of the 802.16 physical layer  540 . 
     An example of the operation of the messaging setup phase of PMP multi-hop relay is as follows. CID distribution controller  528  receives, from another station, a DSx message which contains an ingress CID. CID distribution controller  528  also received a path list of Node IDs from the source station to the destination station. CID distribution controller  528  then uses the Node ID for the next station to allocate egress CID  534  for the connection to that next station. CID distribution controller  528  also creates entries in CID mapping table  535  for ingress CID  532  and the newly allocated egress CID  534 . Finally, CID distribution controller  528  reserves air link bandwidth for the next connection against the associated QoS parameters. CID distribution controller then replaces the ingress CID in the DSx message with egress CID  534 . The DSx message is then queued for delivery through QoS buffer  536  by frame scheduler  538  by means of 802.16 physical layer  540 . Based on the destination information embedded in the path list contained in the DSx message sub-header and the service flow ID in DSx message body, RS  504  can identify the CID mapping table entry as being either a transport CID mapping or a tunnel CID mapping. 
     Of course, since any of the air links in communication with RS  504  may include multiple service flows (and therefore multiple CIDs), CID mapping table  535  may include multiple rows for multiple ingress CIDs and their corresponding egress CIDs. 
     As will be in explained in more detail below, once there are corresponding ingress and egress CIDs in each CID mapping table in each relay station between a source node and a destination node, the messaging setup phase will be concluded. Traffic between the source code and the destination node will then be routed without further need for the involvement of CID distribution controller  528 . For each received MAC payload message, CID swapper  530  will take out transport CID  409  from MAC PDU generic header (or tunnel CID  422  from relay sub-header  415  as the case may be), then look up CID mapping table  535 , find the corresponding egress CID, swap the CID, and further transmit the MAC payload PDU to the next hop. Thus, there is a decoupling of the control plane from the data plane. Due to multi-tier PMP node in the multi-hop relay network, each frame is broadcast to all the downstream nodes. Each intermediate node will simply drop the MAC PDU if CID swapper  530  cannot find any entry in CID mapping table  535  (which means the MAC PDU received is not targeted to the RS′ subordinate tree). 
     In some embodiments, both CID distribution controller  528  and CID swapper  530  may collaborate with handoff control functions to provide fast re-route for mobility. 
     Specific mechanisms of data plane processing are detailed below. 
       FIG. 6  is a diagram illustrating end-to-end MAC layer CID processing for a PMP multi-hop relay scenario over three hops. Shown is BS  502  which is in communication with RS  504  via air link  526 , RS  504  which is in communication with RS  506  via air link  542 , and RS  506  which is in communication with SS  508  via air link  558 . 
     In BS  502 , the 802.16 protocol is represented by Convergence Layer  510  (CS) and MAC layer  512 . MAC layer  512  is comprised of CID mapping table  511  mapping IP/Ethernet data flow  514 , to SFID  516  to CID  518 . Contained within MAC layer  512  are QoS buffers  520  which represents the queuing of packets according to QoS for delivery by the frame scheduler  522  by means of the 802.16 physical layer  524 . 
     RS  504  is the same as was shown and described in  FIG. 5 . RS  506  is the same as RS  504  and as a result, CID swapper  544 , CID distribution controller  546 , CID mapping table  545 , egress CID  548 , ingress CID  550 , QoS buffer  552 , frame scheduler  554  and 802.16 PHY will not be further described. 
     In SS  508 , the 802.16 protocol is represented by Convergence Layer  560  (CS) and MAC layer  513 . MAC layer  513  is comprised of CID mapping table  591  mapping IP/Ethernet  564 , to SFID  566  to CID  568 . Contained within MAC layer  512  is QOS buffer  561  which represents the queuing of packets for delivery according to QoS by the frame scheduler  562  by means of the 802.16 physical layer  589 . 
     An embodiment of the set-up phase of PMP multi-hop relay is as follows. The MAC header (see MAC header  400  in  FIG. 4 ) and relay sub-header (see relay sub-header  415  in  FIG. 4 ) contains a path list of Node IDs for BS  502 , RS  504 , RS  506  and SS  508  which are transmitted along with a Dynamic Service Message (DSx) containing a transport CID for the connection between BS  502  and RS  504  across air link  526  to RS  504 . The path list in the relay sub-header is used to pilot the packet along the path from source node to destination node. 
     At RS  504 , an ingress CID  532  for the connection between BS  502  and RS  504  is received at CID distribution controller  530 . CID distribution controller  530  then creates an entry in CID mapping table  535  for ingress CID  532 . The path list in the relay sub-header is also received by CID distribution controller  530  containing the Node ID of RS  506  which is the next hop along the transmission path. CID distribution controller  530  then allocates a CID for the next connection along the path from the source node to the destination node, i.e. from RS  504  to RS  506 . This is referred to as egress CID  534  which is then written into table  535  such that ingress CID  532  and egress CID  534  correspond with each other. CID distribution controller  528  then replaces the ingress CID  532  for the egress CID  534  in DSx message  470 . The MAC header, relay sub-header and DSx message are then forwarded to QOS buffer  536  and frame scheduler  538 , and then transmitted on air link  542  to the next hop (in this case RS  506 ) by means of the 802.16 physical layer  540 . 
     At RS  506 , all of the same functions are carried out on the MAC header, relay sub-header and DSx message as were carried out by RS  504 . At RS  506 , egress CID  534  which is a CID for the connection between RS  504  and RS  506  is received at CID distribution controller  546 . On receipt, egress CID  534  will be referred to as ingress CID  548 . CID distribution controller  546  then creates an entry in table  545  for ingress CID  548 . The path list in the Relay sub-header is also received by CID distribution controller  546  containing the Node ID of SS  508  which is the next hop along the transmission path. CID distribution controller  546  then allocates a CID for the next connection along the path from the source node to the destination node, i.e. from RS  506  to SS  508 . This is referred to as egress CID  550  which is then written into table  545  such that ingress CID  530  and egress CID  548  correspond with each other. CID distribution controller  544  then replaces the ingress CID  545  for the egress CID  550  in DSx message  470 . The MAC header, relay sub-header and DSx message are then forwarded to QOS buffer  552  and frame scheduler  554 , and then transmitted on air link  558  to the next hop (in this case SS  508 ) by means of the 802.16 physical layer  556 . 
     At SS  508 , the destination station is reached. At this point, the messaging setup phase is concluded because the destination node has been reached and there are corresponding ingress and egress CIDs stored in each CID mapping table in each relay station between BS  502  and SS  508 . Message traffic between BS  502  and RS  508  will then be routed via RS  504  and RS  506  without further need for CID distribution controller  528 ,  546 . CID swapper  530 ,  544  will use CID mapping tables  535 ,  545  to map the correspondence between ingress CIDs and egress CIDs along the pathway between BS  502  and RS  508 , and vice versa (i.e. both uplink and downlink message traffic). 
     Note that the above description applies generally to the case where ingress CIDs and egress CIDs are transport CIDs. The same description also applies in the case of tunnel CIDs, though in this case an ingress CID and its corresponding egress CID in a CID mapping table may be the same. 
     Network layer operation involvement is not required for the message traffic phase. 
       FIG. 7  is a schematic diagram of network  200  within which BS  502 , RS  504 , RS  506  and SS  508  detailed above with reference to  FIG. 6  may be situated, with details concerning the transmission over air links  526 ,  542 ,  558  of DSx signalling messages  310 ,  330 , and  340  during the messaging setup phase of PMP multi-hop relay. RS&#39;s  210 ,  220 ,  222 , and  224 , and SS  230 ,  232 ,  234  are not involved in the example described below and are included for illustration purposes only. 
     DSx signalling message  310  includes a DSx generic header  312  containing a Management CID  314 , a Relay sub-header  316  containing a path list  318  (in this case, Node IDs identifying the route between BS  502  and SS  508  as BS  502   RS  504   RS  506   SS  508 ) and a DSx message body  320  containing SFID  322  and Transport CID 1    324 . Transport CID 1  defines a connection on air link  526  as the route between BS  502  and RS  504 . 
     DSx signalling message  310  is sent by BS  502  to RS  504  where it is received. Based on path list  318 , RS  504  determines that signalling message  310  should be forwarded on to RS  506 . Transport CID 2    325  is then allocated to define a connection on air link  372  as the route between RS  506  and RS  508 . In DSx message body  320 , Transport CID 1    324  is swapped out and replaced with Transport CID 2    325 . DSx signalling message  330  containing Transport CID 2    325  is then sent to RS  506 . 
     RS  506  receives DSx signalling message  330  and based on path list  318  determines that signalling message  330  should be forwarded on to SS  508 . Transport CID 3    327  is then generated to define connection  374  as the route between RS  506  and SS  508 . In DSx message body  320 , Transport CID 2    325  is swapped out and replaced with Transport CID 3    327 . Signalling message  340  is then relayed on to SS  508  which is the destination node for the packet. 
     Note that DSx signalling messages  310 ,  330  and  340  may include tunnel CIDs in the place of transport CIDs in DSx message body  320 . In this case, the CID mapping tables contained within RS  504  and RS  506  would contain correspondences between tunnel CIDs instead of transport CIDs. It is also noted that an end-to-end transport CID path and an end-to-end tunnel CID path would be created using separate DSx messages as they have different destinations. 
     Traffic Processing—DL MAP Implementation 
     The traffic phase of PMP multi-hop relay functionality will now be described. In one embodiment of the traffic phase of PMP multi-hop relay, a DL MAP (downlink multiplexing access profile) is broadcast by the base station in each downlink frame. The DL MAP associates a respective Orthogonal Frequency-Division Multiplexing (OFDM) time frequency resource, related coding schema, the position of data burst with each CID to be given resources during a given scheduling interval. Each individual receiver uses the MAP together with knowledge of which CID is theirs to determine where their data burst content will be positioned within the received OFDM downlink frame and what coding method should be used to decode OFDM symbols. In a DL, subchannels may be intended for different receivers. In each OFDM DL frame, a data burst can contain multiple MAC PDUs. In DL-MAP, CIDs are used to indicate which data burst is to be designated to which SS. An individual receiver distinguishes data destined for it by means of a CID. Depending on service flow characteristics, this CID could be broadcast, multicast, unicast, or null. 
     For this embodiment, the CID used in DL-MAP could be a tunnel CID (i.e. a CID stack) for downstream traffic delivery. CID swapping for traffic involves each intermediate node receiving the DL MAP, and swapping out the ingress CID for the egress CID in the MAP. Note that the frequency time resource assigned to the egress CID may differ from that assigned to the ingress CID. Thus, the intermediate node also moves the burst for each CID from its ingress frequency time resource assignment to its egress frequency time resource assignment. 
     Referring now to  FIGS. 8A and 8B  a specific example of how CID swapping for traffic can be handled by an intermediate node.  FIG. 8A  shows an example frame structure transmitted by a first node, for this example assumed to be BS  502  of  FIG. 7 , while  FIG. 8B  shows an example frame structure transmitted by a subsequent relay station, for this example assumed to be RS  504  of  FIG. 7 . OFDMA frame  1000  contains DL sub-frame  1001  and UL sub-frame  1003 . For simplification purposes, further details regarding the OFDMA frame are not shown or described. Contained within DL sub-frame  1001  is DL-burst 1    1004  which is a DL burst intended for reception by SS  508 . Also contained within DL sub-frame  1001  is DL-MAP  1002  which contains information regarding how OFDMA frame  1000  as a whole will be used. For example, DL-MAP  1002  might contain CID 1  which is the CID for the connection between BS  502   205  and RS  504  of  FIG. 7 . DL-MAP  1002  also contains information which maps CID 1  to DL Burst 1 . 
     As described in detail above, after the messaging setup phase is complete, RS  504  contains a CID swapping table with an entry for CID 1 . (See, for example, CID swapping table  535  in  FIG. 6 ). RS  504  will retrieve CID 1  contained in DL MAP  1002  and use it as an index to check the CID swapping table for an ingress CID which matches CID 1 . Once this is found, the corresponding egress CID (hereinafter referred to as CID 2 ) will be retrieved from the CID swapping table. RS  504  will then swap CID 1  with CID 2  and generate a new DL-MAP using CID 2 . 
       FIG. 8B  is a schematic diagram of an OFDMA frame after CID swapping is performed by RS  504 . In this case, contained within DL sub-frame  1001  is DL-burst 2    1012  which is a DL burst intended for reception by RS  506 . Also contained within DL sub-frame  1001  is DL-MAP  1002  which contains CID 2 , as well as information pertaining to a mapping between CID 2  and DL Burst 2    1012 . 
     CID swapping similar to that described above occurs at each relay node between BS  502  and SS  508 , including RS  506 , until SS  508  is reached. In this embodiment, the relay node would not decode the data bursts; therefore the transport CID contained in the MAC-PDU header is untouched. 
     Traffic Processing—Per-Packet CID Swapping Implementation 
     In another embodiment of the traffic phase of PMP multi-hop relay, in the case of DL-MAP contains a null CID for a particular data burst, there is no CID contained in DL MAP  1002  of  FIG. 8A . Instead, each DL Burst (such as DL Burst 1   1004 ) contains MAC PDUs with assigned CIDs. Where a CID is not specified in DL-MAP  1002 , then each intermediate node between a BS and a SS has to decode each burst (which are composed of several MAC-PDUS) and the MAC-PDUs inside that burst. In this embodiment of the traffic phase, CID swapping will be done for each MAC-PDU. 
       FIG. 9A  is a schematic diagram of network  200 , which for this embodiment is used to illustrate the traffic phase of PMP multi-hop relay where per packet CID swapping is performed and where there is no tunnel CID.  FIG. 9A  illustrates the same network  200  as shown in  FIG. 7 . The description of elements already described in connection with  FIG. 7  will not be repeated. 
     MAC PDU  1040  is a packet sent by BS  502  which is destined for SS  508  via RS  504  and RS  506 . MAC PDU  1040  contains MAC generic header  1060  and payload  1056 . MAC generic header  1050  contains transport CID 1 . Transport CID 1  defines connection  370  as the route between BS  502  and RS  504 . 
     RS  504  then receives MAC PDU  1040 . As described in detail above, after the messaging setup phase is complete, RS  504  contains a CID swapping table with an entry for transport CID 1 . (See, for example, CID swapping table  535  in  FIG. 6 ). RS  504  will retrieve transport CID 1  contained in MAC PDU  1040  and use it as an index to check the CID swapping table for an ingress CID which matches transport CID 1 . Once this is found, the corresponding egress CID (hereinafter referred to as transport CID 2 ) will be retrieved from the CID swapping table. RS  504  will then swap transport CID 1  with transport CID 2  and generate new MAC PDU  1042  using transport CID 2    1052 . There may also be a relocation of the packet within the OFDM frequency time space. Note that some data bursts may be dropped by the relay node if they are not targeted to the RS&#39;s subordinate tree. 
     RS  506  then receives MAC PDU  1042 . As explained above, RS  506  contains a CID swapping table with an entry for transport CID 2 . RS  506  will retrieve transport CID 2  contained in MAC PDU  1042  and use it as an index to check the CID swapping table for an ingress CID which matches transport CID 2 . Once this is found, the corresponding egress CID (hereinafter referred to as transport CID 3 ) will be retrieved from the CID swapping table. RS  206  will then swap transport CID 2  with transport CID 3  and generate new MAC PDU  1044  using transport CID 3  which will be forwarded to the packet&#39;s intended destination, SS  208 . 
       FIG. 9B  is a schematic diagram of a multi-level relay network illustrating in the traffic phase where there is a tunnel CID. Note that MAC PDUs  1040 ,  1042 , and  1044  may optionally include a relay sub-header  1082  including a tunnel CID. For per-flow relay, if a tunnel CID is included within relay sub-header  1082 , then a RS will swap the tunnel CID in the relay sub-header leaving the transport CID untouched. 
       FIG. 9B  illustrates the same network  200  as shown in  FIG. 9A . The description of elements already described in connection with  FIG. 9A  will not be repeated. MAC PDU  1044  is a packet sent by SS  508  which is destined for BS  502  via RS  506  and RS  504 . MAC PDU  1044  contains MAC generic header  1070  and payload  1056 . MAC generic header  1070  contains a transport CID  1054 . 
     RS  506  then receives MAC PDU  1044 . As described in detail above, after the messaging setup phase is complete, RS  506  contains a CID swapping table with an entry for tunnel CID 2    1084  (See, for example, CID swapping table  545  in  FIG. 6 ). Assuming RS  506  has been configured to conduct traffic aggregation for upstream traffic, RS  506  will create relay sub-header  1085  for tunnel CID 2    1084 , attaches sub-header  1085  into received MAC PDU  1044  (hereinafter referred to as MAC PDU  1042 ) and further forward the new MAC PDU  1042  upward. 
     RS  504  then receives MAC PDU  1042 . As already explained, RS  504  contains a CID swapping table with an entry for tunnel CID 2    1084 . RS  504  will retrieve tunnel CID 2    1084  contained in relay sub-header  1085  and use it as an index to check the CID swapping table for an ingress CID which matches tunnel CID 2    1084 . Once this is found, the corresponding egress CID (hereinafter referred to as tunnel CID 1    1080 ) will be retrieved from the CID swapping table. RS  504  will then swap tunnel CID 2    1084  with tunnel CID 1    1080  and generate new relay sub-header  1082  using tunnel CID 1    1080  in MAC PDU  1042  (hereinafter referred to as MAC PDU  1040 ), and then MAC PDU  1040  will be forwarded to the packet&#39;s intended destination, BS  502 . Note that in RS  504 , the transport CID  1054  is untouched. 
     When BS  502  receives MAC PDU  1040 , it takes out transport CID  1054  as index and looks up the mapping table to find out correspondent SFID, and executes service convergence layer functions to transform MAC PDU to service flow packets (i.e., IP/Ethernet). 
       FIG. 10  is a signalling flow illustrating control/data message flow according to an embodiment of the invention.  FIG. 10  is described in conjunction with some elements already described in connection with  FIG. 2 . 
     Messages  902 ,  912 ,  904 ,  914 ,  906 , and  916  represent capacity and security messages which are sent during network setup. RS  63  enters the network and “Relay” Network entry message is sent to/from BS  60 . PMP Network Entry message  912  is then sent to/from SS  68 . SS  68  enters the network and a RNG-REQ (ranging request) message  914  is sent to RS  63 . RS  63  then sends a RNG-REQ (ranging request) message  904  to BS  60 . BS  60  then sends a RNG-RSP (raging response) message  906  to RS  63 . RS  63  then sends a RNG-RSP message  916  to SS  68 . 
     The messaging setup phase is then illustrated through the transmission of signalling messages  908 ,  918 ,  910 , and  920 . In this embodiment, the generic DSx message referred to in  FIG. 4  is a Dynamic Service Addition (DSA) messages. DSA-REQ (DSA Request) message  908  sent from BS  60  to RS  63  contains transport CID 1 , SFID, and MAC relay sub-header contains a path-list of node identifiers for BS  60 , RS  63  and SS  68 . After CID replacement at RS  63  in the manner previously described, DSA-REQ message  918  containing transport CID 2 , SFID, and a path-list of node identifiers for BS  60 , RS  63  and SS  68  is then sent to SS  68 . In response, SS  68  sends DSA-RSP (DSP Response) message  920  containing transport CID 2 , SFID, and a path-list of node identifiers for BS  60 , RS  63  and SS  68  is then sent to RS  63 . RS  63  then sends DSP-RSP message  910  containing transport CID 1 , SFID, and a path-list of node identifiers for BS  60 , RS  63  and SS  68  to BS  60 . 
     The message traffic phase is then represented by CID mapping table  950  contained in RS  63 , MAC-PDU  954 , CID swapping function  952 , and MAC-PDU  956 . This is the second embodiment of the message traffic phase described above in connection with  FIG. 10 . An incoming MAC-PDU  954  from BS  60  containing a CID will arrive at BS  63 . CID swapper  952  will use CID mapping table  950  to swap ingress CID 1  with egress CID 2 . MAC-PDU  956  will then be routed to SS  68 . Message traffic can also be routed in the uplink direction from SS  68 , RS  63  to RS  60  as is shown by the double arrowhead lines. 
     As described above, PMP multi-hop relay provides CID swapping at each RS to provide an end-to-end CID label path between a BS and a SS. The multi-hop relay protocol supports connection orientated data relay in IEEE 802.15. The protocol can be applied to fixed, nomadic and mobile RS relay topology. It is also backwards compatible with the existing IEEE 802.16 standard with only minor changes in the current interface. It is also easy to migrate from relay mode to mesh mode. Support is provided for both OFDM and OFDMA. 
     In some embodiments the PMP multi-hop relay is compatible with IEEE 802.15. In some embodiments, a RS is utilized between a BS and a SS. In some embodiments multiple RS are located between a BS and a SS. Some implementations are used as an alternative to a single hop PMP architecture. Some implementations are used in conjunction with a single hop PMP architecture. 
     In some embodiments, the BS has a fixed location. In some implementations one or more RS have fixed locations. In other implementations one or more RS are nomadic or mobile. The SS is fully mobile-enabled. However, in some embodiments the SS may be stationary. Mobile RS and SS may relocate to other cells having a different BS as well as within the same cell. 
     In some embodiments, the present invention provides an approach for end-to-end connection management in a multi-tier PMP topological network architecture in 802.16 networks. The approach can also be applied to a fully mesh 802.16 access network. 
     In some embodiments, the present invention supports fast re-route for SS handoff by on-demand signalling or pre-build-up CID tunnel. In some relay nodes, there is a routing controller which handles source routing protocols for route creation and maintenance. The routing controller interfaces with the CID distribution controller to provide the routing paths for connection oriented creation and maintenance. CID swapping can support these functions by providing an Application Program Interface (API) to these control modules. 
     Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.

Metadata:
Filing Date: 20060703
Publication Date: 20131008
Grant Date: 20131008
Priority Date: 20050817
Inventors: WANG GUO QIANG
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W8/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W28/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L47/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/2606", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L47/6215", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L47/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W40/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/155", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W80/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/155", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W40/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/2606", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L47/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L47/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W80/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L47/6215", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 37757276