WO2008106797A1 - Procédés et systèmes pour des réseaux sans fil avec des relais - Google Patents

Procédés et systèmes pour des réseaux sans fil avec des relais Download PDF

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Publication number
WO2008106797A1
WO2008106797A1 PCT/CA2008/000450 CA2008000450W WO2008106797A1 WO 2008106797 A1 WO2008106797 A1 WO 2008106797A1 CA 2008000450 W CA2008000450 W CA 2008000450W WO 2008106797 A1 WO2008106797 A1 WO 2008106797A1
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WO
WIPO (PCT)
Prior art keywords
relay
transmission resource
dedicated
base station
resource
Prior art date
Application number
PCT/CA2008/000450
Other languages
English (en)
Inventor
Hang Zhang
Peiying Zhu
Fong-Mo-Han
Wen Tong
Nimal Senarath
David Steer
Derek Yu
Original Assignee
Nortel Networks Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nortel Networks Limited filed Critical Nortel Networks Limited
Priority to EP08733554A priority Critical patent/EP2123079A4/fr
Publication of WO2008106797A1 publication Critical patent/WO2008106797A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/02—Resource partitioning among network components, e.g. reuse partitioning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H04B7/15528—Control of operation parameters of a relay station to exploit the physical medium
    • H04B7/15542—Selecting at relay station its transmit and receive resources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2603—Arrangements for wireless physical layer control
    • H04B7/2606—Arrangements for base station coverage control, e.g. by using relays in tunnels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/042—Public Land Mobile systems, e.g. cellular systems
    • H04W84/047—Public Land Mobile systems, e.g. cellular systems using dedicated repeater stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/20—Interfaces between hierarchically similar devices between access points

Definitions

  • the invention relates to the field of wireless communications, more specifically to systems and methods for supporting Orthogonal Frequency Division Multiplexed (OFDM) communication using relays.
  • OFDM Orthogonal Frequency Division Multiplexed
  • a mobile station (MS) in a given cell is only served by its serving base station (BS) .
  • BS serving base station
  • One drawback of such wireless networks is that MSs near an edge of the given cell suffer performance loss due to interference from other cells in cellular networks and propagation loss in non-cellular networks which results in limited data rates and gaps in coverage of the given cell.
  • the method further comprises the base station transmitting at least one of: an assignment of the dedicated transmission resource portion for a link between the base station and at least one relay one hop away from the base station along the path; an assignment of the dedicated transmission resource portion for a link between a relay that is more than one hop away from the base station along the path and at least one subordinate relay along the path.
  • the method further comprises: the subordinate relay transmitting an indication of an amount of transmission resource and a particular location within the transmission resource to be used as the dedicated transmission resource portion to a one hop away subordinate relay.
  • the method further comprises the base station transmitting: the assignment of the dedicated resource portion for the link of the relay one hop away from the base station along the path.
  • the base station transmitting an assignment of the dedicated transmission resource portion comprises: the base station transmitting an indication of an amount of transmission resource to be used as the dedicated transmission resource portion to a subordinate relay.
  • the base station transmitting an assignment of the dedicated transmission resource port-ion comprises: the base station transmitting an indication of an amount of transmission resource and a particular location within the transmission resource to be used as the dedicated transmission resource portion to a subordinate relay.
  • the method further comprises: the relay transmitting an indication of an amount of transmission resource and a particular location within the transmission resource to be used as the dedicated transmission resource portion to the subordinate relay that is more than one hop away from the base station along the path.
  • transmitting the assignment comprises transmitting a media access control (MAC) layer information element (IE) .
  • MAC media access control
  • IE layer information element
  • the method further comprises: a relay along the path sending a request to the base station for a dedicated transmission resource assignment for a link between the relay sending the request and the base station.
  • the method further comprises: the base station receiving a request for a dedicated transmission resource assignment; the base station considering the request before allocating the dedicated transmission resource.
  • each of the at least one relays managing the non-dedicated transmission resource portion in a distributed manner comprises: a relay along the path assigning a non-dedicated portion of the transmission resource to at least one link between the relay assigning the non-dedicated portion of the transmission resource and a subordinate relay along the path.
  • the method further comprises the relay transmitting: an assignment of the non-dedicated transmission resource portion the subordinate relay along the path.
  • the marhod further comprises: the relay transmitting an indication of at least one of: an amount: of transmission resource; and a particular location within the transmission resource to be used as the non-dedicated transmission resource portion to the subordinate relay along the path.
  • the method further comprises: a relay along the path determining for what purpose the dedicated transmission resource is used in a link to a subordinate relay.
  • a purpose for which the dedicated transmission resource is used is for a delay sensitive service flow.
  • the method further comprises when using a HARQ (hybrid automatic repeat request) retransmission scheme, performing either one of: a) transmitting a first transmission on the dedicated resource and retransmitting a portion of or all of the first transmission on an additional, dynamically assigned resource; and b) controlling a first transmission and subsequent retransmissions on the dedicated resource by including an additional dedicated control channel to transmit information regarding whether a given transmission is the first transmission or a subsequent retransmission.
  • HARQ hybrid automatic repeat request
  • retransmitting a portion of or all of the first transmission on an additional, dynamically assigned resource comprises: transmitting an indication of an amount of transmission resource and/or a particular location within the transmission resource to be used as a HARQ retransmission resource to a subordinate relay.
  • transmitting the indication of an amount of transmission resource and/or a particular location within the transmission resource to be used as a HARQ retransmission resource to a subordinate relay comprises transmitting a media access control (MAC) layer information element (IE) containing the indication.
  • MAC media access control
  • IE layer information element
  • a method for reporting information on a dedicated resource from a relay to a superodinate relay or a base station comprising: transmitting a, type of reporting information / transmitting a value associated with the type of reporting information that further defines the reporting information.
  • transmitting a type of reporting information comprises transmitting an indication of at least one of the following types of information: channel quality; closed loop MIMO related feedback; uplink bandwidth request; flow control; uplink HARQ control; and fast base station selection.
  • transmitting the type of reporting information comprises transmitting a first number of bits used to identify the type; and transmitting the value associated with the type comprises transmitting a second number of bits used to identify the value.
  • the first number of bits is 3 and the second number of bits is either 3 or 6.
  • a method for requesting a dedicated channel transmission resource for a link between a base station and a relay in an uplink direction from the relay to the base station or for a link between a relay and a superordinate relay in an uplink direction from the relay to the superordinate relay comprising: sending a message requesting a dedicated channel transmission resource; receiving an assignment of the dedicated channel transmission resource.
  • the relay sending a message comprises: sanding the message in the form of a media access control (MAC) layer header.
  • MAC media access control
  • receiving an assignment comprises: receiving an assignment in the form of a media access control (MAC) layer information element (IE) .
  • MAC media access control
  • IE layer information element
  • a message having substantially the same format as the message used for requesting the dedicated channel transmission resource is used for each of: acknowledging the assignment of the dedicated channel transmission resource; and sending a HARQ retransmission request.
  • a method for requesting a dedicated channel transmission resource for a link between a base station and a relay in an uplink direction from the relay to the base station or for a link between a relay and a superordinate relay in an uplink direction from the relay to the superordinate relay comprising: receiving a message indicating a request for a dedicated channel transmission resource; determining an allocation for the dedicated channel transmission resource based at least in part on the message; sending an assignment of the dedicated channel transmission resource.
  • receiving a message comprises: receiving the message in the form of a media access control (MAC) layer header.
  • MAC media access control
  • sending an assignment comprises: sending an assignment in the form of a, media access control (MAC) layer information element (IS) .
  • MAC media access control
  • IS layer information element
  • sending an assignment of the dedicated channel transmission resource comprises: in a centralized management scheme, the base station sending an assignment of the dedicated channel transmission resource to all subordinate relays; and in a distributed management scheme, the base acation sending an assignment of the dedicated channel transmission resource to relays one hop away from the base station and the superordinate relay sending an assignment of the dedicated channel transmission resource to relays one hop away from the superordinate relay.
  • At least one of size of an allocated dedicated channel transmission resource and allocation interval of an allocated dedicated channel transmission resource can be increased or decreased based on at least one of traffic load and channel conditions.
  • the traffic load and/or channel conditions are calculated at least one of: periodically; and in response to specific events.
  • aspects of the invention include a base station relay, and/or mobile station each adapted to perform methods described above.
  • Figure 1 is a block diagram of an example of a network including a base station, relay stations and mobile stations,-
  • Figure 2 is a flow chart for a method of management of transmission resources according to an embodiment of the invention.
  • Figure 3 is a flow chart of another method of management of transmission resources according to an embodiment of the invention.
  • Figure 4A is a block diagram of another example of a network including a base station, relay stations and mobile stations;
  • Figure 43 is a schematic diagram illustrating a transmission resource allocated to links of the network of Figure 4A;
  • Figure 5A is a block diagram of another example of a network including a base station, relay stations and mobile stations;
  • Figure 5B is a schematic diagram illustrating a transmission resource allocated to links of the network of Figure 5A before and after a request for additional transmission resource is requested for a service flow;
  • Figure 6A is a block diagram of an example of a network including a serving base station, a target base station, relay stations and a moving relay station being handed off from the serving base station to the target base station;
  • Figure 6B is a schematic diagram illustrating a transmission resource allocated to links of the network of Figure 6A before and after a handoff occurs;
  • Figure 7 is a flow chart for a method of requesting and allocating a dedicated transmission resource according to an embodiment of the invention.
  • Figure 8 is a block diagram of a cellular communication system
  • FIG. 9 is a block diagram of an example base station that might be used to implement some embodiments of the present invention.
  • Figure 10 is a block diagram of an example wireless terminal that might be used to implement some embodiments of the present invention
  • Figure 11 is a block diagram of a logical breakdown of an example OFDM transmitter architecture that might be used to implement some embodiments of the present invention.
  • Figure 12 is a block diagram of a logical breakdown of an example OFDM receiver architecture that might be used to implement some embodiments of the present invention.
  • various physical layer designs and procedures are provided for enabling relay based communications that may find applications in an IEEE 802.16 based network.
  • the concepts described herein are not, however, limited in this regard and may be applicable to any OFDM based systems, such as 3GPP and 3GPP2 evolutions.
  • Figure 1 shows an example of a wireless system, for example an OFDM network: that includes relays.
  • a base station (BS) 130 that is in communication with one or more mobile stations (MS), only one shown MS-I 132, and one or more first tier relay stations (RS), only one shown RS-I 138.
  • Some of the first tier (one hop away from BS) relay stations are in communication with one or more second tier (two hops away from BS) relay stations.
  • RS and MS the same number of hops away from the BS are said to be in the same tier.
  • RS-I 138 is in communication over a communication link with second tier RS-2 140.
  • Each relay station can serve one or more mobile stations. For example,
  • RS-I 138 is in communication over a communication link with MS- 2 134
  • RS-2 140 is in communication over a communication link with MS-3 136.
  • there is a two- tier relay structure such that there is a maximum of three hops to reach a mobile station. Larger numbers of hops are contemplated.
  • the specific network of Figure 1 is to be considered only an example. More generally, an arbitrary arrangement of base stations, relay stations, and mobile stations is contemplated. The mobile stations will change over time due to their mobility. Some embodiments support only fixed relays; others support mobile relays, while further embodiments support both fixed and mobile relays.
  • traffic flow is not necessarily evenly distributed on all links. Usually a first hop is a bottleneck for traffic flow. Ideally, traffic flow should be managed at each relay so that the input data rate and output data rate are substantially equal .
  • a fully centralized resource management scheme in which the base station handles all aspects of resource management, can handle the above, but incurs significant delay, overhead and multi-hop relay base station (MR-BS) complexity.
  • MR-BS multi-hop relay base station
  • a fully distributed resource management scheme in which resource management: tasks are distributed amongst the base station and relays may cause significant data dropping due to the lack of a global view.
  • a method for managing transmission resources including a dedicated transmission resource portion and a non-dedicated transmission resource portion in a system having a base station and at least one relay station in which the base station the base station manages the dedicated transmission resource portion in a centralized manner and/or a. distributed manner and each of che at least one relays manages the non-dedicated transmission resource portion in a distributed manner.
  • management of transmission resource allocation may be performed for one or both of uplink (UL) and downlink (DL) .
  • UL is transmitting in a direction from a mobile station or relay station to a superordinate station, a superordinate station being defined as a relay one or more hops closer to the base station, or the base station itself.
  • DL is transmitting in a direction from a base station or relay to a subordinate station, a subordinate relay being defined as a relay in a tier one hop further away from the base station than a relay of a given tier.
  • a further task in the management of transmission resource allocation may include dedicating a portion of a transmission resource to a particular type of service .
  • Embodiments of the present invention include methods fcr a base station to dedicate transmission resources for at least one relay one hop away, and ir. some cases for relays one or more subsequent hops away.
  • transmission resources that are not dedicated may be shared amongst subordinate relays.
  • Embodiments of the inventive resource management, scheme may result in one or more of: a reduction in delay for certain service flows, a reduction in the buffer size of an RS node, a reduction in the packet drop rate, and a reduction in the amount of signalling overhead.
  • allocating a dedicated transmission resource involves three steps: 1) determining a maximum allowed amount of transmis ⁇ ion resource on each link, 2) assigning a dedicated resource that is at least a portion of the maximum allowed amount of the transmission resource on each link; and 3) sharing the portion of the maximum allowed amount of the transmission resource on each link that is not assigned as a dedicated resource to one or more relays or mobile stations one hop further away in the direction of a greater number of hops away.
  • the base station performs this task for the relays one hop away from the base station and the relays on each tier perform a similar task for subordinate relays one hop away.
  • relays on each tier may perform resource management for non-dedicated resources of the transmission resource of a given link on a per-frame basis for each of its one hop subordinate relays.
  • the resource management performed by the relays enables dynamic and/or short-term allocation of the transmission resources.
  • the non-dedicared portion of the transmission resource of the given link i.e. the difference between the maximum amount of the transmission resource and the R-link resource cap of the given link, is shared among one or more of the one hop away subordinate relays being served by the given relay.
  • the dedicated traffic resource is allocated or updated in response to any number of events.
  • A. list of events includes, but is not limited to, when a service flow is granted, closed or handed off, upon entry into the network of a new relay, or when a new mobile station enters a network via an access relay.
  • the base station transmits an indication of an amount of transmission resource to be used as the dedicated resource to a subordinate relay.
  • the subordinate relay transmits an indication of an amount of transmission resource and/or a particular location within the transmission resource to be used as the dedicated transmission resource portion to a one hop away subordinate relay.
  • a method for implementing of a management scheme according to embodiments of the invention, in particular based on a centralized scheme for assigning dedicated transmission resources, will now be described with reference to Figure 2.
  • a first step 2-1 involves a base station assigning a maximum capacity for the transmission resource for each link in the path.
  • a second step 2-2 involves, foe each link in the path, the base station assigning less than the maximum capacity for the link as a dedicated transmission resource.
  • a third step 2-3 involves the base station transmitting an assignment of the dedicated transmission resource for a link between the base station and at least one relay one hop away from the base station along the path.
  • a fourth step 2-4 involves the base station transmitting an assignment of the dedicated transmission resource for a link between a relay that is more than one hop away from the base station along the path and at least one subordinate relay along the path.
  • a fifth step 2-5 involves a relay along the path assigning a non-dedicated portion of the transmission resource to at least one link between the relay and a subordinate relay along the path.
  • the non-dedicated resource 213 is split into equal portions and allocated as non-dedicated resource 223 between R1 220 and R11 230 and as non-dedicated resource 226 between R1 220 and R12 231, respectively.
  • the dedicated resource 212 and the non-dedicated resource 213 are equally divided for the links between R1 220 and RlI 230 and between R1 220 and R12 230, however the allocation of the dedicated resource portion and the non-dedicated resource portion is implementation specific and can be allocated in any manner that reflects the needs of the links involved. Similar allocations of resources are illustrated for tile links between NR-BS 210 and R2 221, between R2 221 and R21 232, between MR-BS 210 and R3 222, and between R3 222 and R31 233.
  • Figure 5A(i) illustrates a portion of a network representing a signal path between MR-BS 310 and a mobile station MS 340, via a first relay RSl 320 and a second relay RS2 330 , prior to MS 340 requesting a dedicated resource for " Che delay sensitive service flow.
  • Column 312 between MR-BS 310 and RSl 320 represents an entire resource allocated for UL signalling between these two nodes.
  • the shaded portion of column 312, indicated as 313, represents a portion of the resource for existing dedicated resources.
  • the unshaded portion of column 312, indicated as 314, represents a non-dedicated resource available for other types of services.
  • Column 322 between RSl 320 and RS2 330 represents an entire resource allocated for UL signalling between these two nodes.
  • the shaded portion of column 322, indicated as 323, represents a portion of the resource for existing dedicated resources.
  • the unshaded portion of column 322, indicated as 324, represents a non- dedicated resource available for other types of services.
  • Figure 6 ⁇ is a signal flow diagram that illustrates signal flows between the nodes.
  • a first signal flow 460 represents signalling involved for handoff of MRS 420 from serving MR-BS 410 to target MR-BS 430.
  • a second signal flow 455 is a message sent from target MR-BS 430 to RSl 440 that informs RSl 440 of an increase to the currently allotted dedicated resource between target MR-BS 430 and RSl 440 by a specified amount to accommodate a dedicated resource used by MRS 420.
  • the size of the dedicated RS UL DCH is large enough for management messages to be sent by the relay.
  • the size of the dedicated RS LJL DCH and/or the allocation interval of the dedicated RS UL DCH can be increased or decreased based on traffic load and/or channel conditions.
  • the traffic load may be calculated periodically and/or in response to specific events.
  • any. and all dedicated channel resources are allocated before non-dedicated UL resources are allocated.
  • the operation is similar to the distributed management scheme, except that the bass station is responsible for assigning the dedicate uplink channel for each hop along the path, instead of only the first hop along the path and allowing the relays on each subsequent hop to allocate the UL DCH.
  • the base station transmits the assignment in the form of an RS UL DCH assignment information element (IE) in an R-MAP message and the assigned transmission resource is available to the relay starting in a next frame after being received.
  • IE RS UL DCH assignment information element
  • a mobile station When a mobile station adjusts its service flow requirements, it impacts the bandwidth requirements on all dedicated relay uplink channels along the path to the base station.
  • the service flow requirements are communicated to the base station via a control mesgage.
  • the base station may adjust the dedicated RS UL DCH cf each relay along the path between the base station and the mobile station.
  • the base station sends a new RS UL DCH assignment using a RS UL DCH assignment IE.
  • Using HARQ transmissions allows more than one transmission of a packet or portions of a packet to ensure that a receiver properly receives the packet.
  • Embodiments of the present invention enable additional transmission resources to be allocated for HARQ retransmissions as necessary.
  • the HARQ used on the RS UL DCH is a negative acknowledgement (NAK) - based HARQ and a hop-by-hop HARQ, which means that is the packet is not forwarded onto a relay one hop away until the entire message has been received and acknowledged at a relay receiving the message.
  • NAK negative acknowledgement
  • a RS UL DCH assignment IE is configured for use with in HARQ operation on the RS UL DCH.
  • the dedicated resource is always used for a first transmission.
  • sequential retransmissions are transmitted on additional dynamically assigned resources without a specific request for additional bandwidth from the node transmitting the sequential retransmissions.
  • an access relay that is providing service to a mobile station or a s ⁇ perordinate relay that is providing service to a relay, assigns an appropriate transmission resource if a negative acknowledgement (NAK) is issued by the access relay, or the superordinace relay, in response to the packet not being properly received.
  • NAK negative acknowledgement
  • the dedicated traffic resource utilization is fully controlled by the relay that is sending rhe retransmissions.
  • the relay utilizes an assigned dedicated control channel to indicate to the superordmate or base station, if the transmission is a first or subsequent retransmission.
  • Packets from multiple MSs/RSs are multiplexed and transmitted through the RS UL DCH on one or more resource blocks.
  • Each DCH resource block can be used for transmitting a single HARQ burst at a time.
  • a number of DCH HARQ channel identifiers are also assigned. Implicit sequential cycling of DCH ACID is used for each occurrence of the periodically assigned resource. The first transmission after enabling HARQ is always HARQ channel 0, therefore the DCH ACID is 0. The DCH ACID is incremented by 1 for each periodic transmission and reset to 0 when a maximum DCH ACID number is reached.
  • sequential retransmissions are transmitted using an additional resource to that of the existing dedicated resources on RS UL DCH.
  • the additional resource is allocated in an information element sent by a superordinate relay or the base station.
  • the dedicated resource When using the dedicated resource, the retransmission is sent using the same HARQ channel and is sent on the next occurrence of the same HARQ channel after the NAK signal.
  • the dedicated resource allocation may minimize signalling overhead for the retransmissions.
  • a one time additional resource is allocated to the HARQ channel that requires transmission. In such a case, the number of the DCH ACID shall be large enough to allow the maximum number of retransmission attempts before the DCH ACID wraps around to a value equal to the starting value.
  • the intermediate RS may also generate a RS UL DCH header with a HARQ retransmission request, so that the base station can allocate resources for the retransmission.
  • the "HARQ type" field in the IE described above indicates that the assignment may be one of four types, in particular, Disabled (no HARQ) , HARQ Chase, HARQ CTC IR, or HARQ CC IR. Subsequent fields of the IE indicate information relevant to these assignments.
  • the IE may not include all of the features included above and/or may include additional features not specifically disclosed herein. More generally, the number of bits in each field, the overall size of the IE and the functions/content of the IE are implementation specific.
  • the "HARQ Control” filed indicated whether the HARQ control is asynchronous or synchronous.
  • the "Retransmission Type” field indicates that the retransmission type may be one of two types, in particular, that HARQ retransmission is to occur in an allocated dedicated UL_DCH or that HARQ retransmission is to occur in a resource assigned in this IE. If the latter type is selected, subsequent fields of the IE indicate wherein the IE these assignments may be made.
  • the IE may not include all of the features included above and/or may include additional features not specifically disclosed herein. More generally, the number of bits in each field, the overall size of the IE and the functions/content of the IE are implementation specific.
  • RS UL DCH Relay uplink dedicated channel
  • the relay requests a dedicated uplink transmission resource for signalling and data transmissions instead of an explicit BW request and allocation for each transmission.
  • the allocated dedicated uplink channel is implemented by the relay after receiving a resource allocation message.
  • the resource allocation message as received as an RS UL DCH assignment IE.
  • the resource assignment is a periodic allocation of uplink bandwidth, no subsequent periodic UL-MAP IE is needed in a UL- MAP message or R-MAP message for allocating UL bandwidth.
  • a relay specifies an average required data rate without specifying an allocation frequency.
  • the base station or one hop away superordinate relay determines a specific BW size and frequency configuration in response t ⁇ the rate based request from the relay.
  • the relay requests a dedicated uplink resource by specifying the dedicated channel request through a signalling header.
  • the relay confirms the successful reception of the resource allocation by sending a DCH assignment acknowledgement.
  • the request is transmitted by the relay in the format of a media access control (MAC) layer header.
  • MAC media access control
  • the MAC layer header may also be used to acknowledge the DCH assignment and be used for transmitting a HARQ retransmission request.
  • the header may not include the features of acknowledging receipt of allocation of the UL DCH and/or requesting HARQ retransmissions ar.d/or may include additional features not specifically disclosed herein. More generally, the number of bits in aach field, the overall size of the header and the functions/content in the header are implementation specific.
  • a Relay Station Dedicated Control Block (RS DCB) that may be used for BW request.
  • RS DCB Relay Station Dedicated Control Block
  • the RS DBC is another manner in which a relay may request a dedicated channel .
  • the RS DCB enables a relay to report information either regularly required or that is urgently needed by superordinate relays.
  • Other types of information that may be included in the RS DBC besides bandwidth request information include, but are not limited to, channel quality information, close loop MIMO related feedback information, Quality of service (QoS) and resource information, up link (UL) HARQ control information (if an UL dedicated traffic resource is also allocated) , flow control information, and fast base station selection (FBSS) information.
  • the RS DBC is 9 bits long. In some embodiments the RS Dae is 6 bits long.
  • the RS DCB is implementation specific, and as such may have a length other than 6 or 9 bits.
  • the RS DCB shall include type identity (TID) information and corresponding value information.
  • TID information is included in a Type field.
  • the type field is 3 bits long enabling up to 8 different types.
  • the corresponding value information is .included in a Value fiald.
  • the type field is 3 bits long enabling up to ⁇ different types.
  • the type field is 6 bits long enabling up to 64 different types.
  • the following is a particular design example for a RS DCB chat is 9 bits in length, 3 bits for a type field and 6 bits for a value field.
  • the following is a particular design example for encoding a RS DCB that is 6 bits in length.
  • the encoding values described above are for a particular example, but more generally, the encoding values are implementation specific.
  • a physical channel is used to trnamsit the RS DCB.
  • an enhanced fast feedback channel (6 bit payload/48 sub-carriers) as defined in IEEE802.16e is used as the physical channel for transmitting the RS DCB.
  • a 9 bit DCB for a 9 bit DCB, three 3 bit feedback channels as defined in IEEE802.16e are used as the physical channel for transmitting the RS DCB. More generally, as the physical channel used to implement RS DCB is implementation specific, any manner of channel allowing transmission of a number of bits used for the RS DCB can be used as ths physical channel.
  • the BS transmits a preamble that is used by mobile stations to measure radio propagation environment and enable MS cell selection.
  • this preamble is transmitted at the start of every DL sub-frame.
  • relay stations When relay stations are present, they also transmit such a preamble in a similar manner so that MS cell selection can be performed as before.
  • This preamble is referred to as a "normal preamble".
  • An embodiment of the invention provides a method of a preamble transmission by the RS that enables RS radio environment measurement without interrupting MS cell selection.
  • a new preamble referred to as an RS_preamble since it is transmitted by the RS only and not the BS, is transmitted in every Nth frame, where N ⁇ 1, once the RS enters the network.
  • the RS_preamble is transmitted in addition to the normal preamble.
  • frames are as defined in 802.16e, but other frame definitions are contemplated.
  • the RS_preamble is transmitted within a UL sub-frame for TDD implementations or a UL sub-frame for FDD implementations. Note this is in contrast to the normal preamble that is transmitted during the DL sub-frame.
  • a pseudo-random noise (PN) sequence for each respective RS preamble may be the same as that of an assigned normal preamble or the PN sequence may be different.
  • first tier RSs can simultaneously transmit their preambles during a first preamble transmission period, and second tier RSs can monitor these; similarly, second tier RSs can simultaneously transmit their preambles during a second preamble transmission period, and first and/or third tier RSs when present can monitor these.
  • first tier RSs transmit their preamble during odd UL sub-frames or UL frames
  • second tier RSs transmit their RS_preamble during even UL sub-frames or UL frames.
  • RS_preamble reuse within a cell is employed. In some embodiments, the RS_preamble is transmitted out of band.
  • a common channel is defined as a primary channel for transmitting an RS_preamble for each respective RS to determine a radio environment measurement.
  • the radio environment measurements are used, for example, to establish topology, for interference avoidance, for carrier or channel assignment and/or for zone configuration.
  • the base station 14 generally includes a control system 20, a baseband processor 22, transmit circuitry 24, receive circuitry 26, multiple antennas 28, and a network interface 30.
  • the receive circuitry 26 receives radio frequency signals bearing information from one or more remote transmitters provided by mobile terminals 16 (illustrated in Figure 8).
  • a low noise amplifier and a filter may co-operate to amplify and remove broadband interference from the signal for processing.
  • Downconversion and digitization circuitry (not shown) will then downconvert the filtered, received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams.
  • the baseband processor 22 receives digitized data, which may represent voice, data, or control information, from the network interface 30 under the control of control system 20, and encodes the data for transmission.
  • the encoded data is output to the transmit circuitry 24, where it is modulated by a carrier signal having a desired transmit frequency or frequencies.
  • a power amplifier (not shown) will amplify the modulated carrier signal to a level appropriate for transmission, and deliver the modulated carrier signal to the antennas 28 through a matching network (not shown) .
  • Various modulation and processing techniques available to those skilled in the art are used for signal transmission between the base station and the mobile terminal.
  • the baseband processor 34 processes the digitized received signal to extract the information or data bits conveyed in the received signal. This processing typically comprises demodulation, decoding, and error correction operations.
  • the baseband processor 34 is generally implemented in one or more digital signal processors (DSPs) and application specific integrated circuits (ASICs) .
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • the base station controller 10 will send data to be transmitted to various mobile terminals 16 to the base stacion 14.
  • the base station 14 may use the channel quality indicators [CQIs) associated with the mobile terminals to schedule the data for transmission as well as select appropriate coding and modulation for transmitting the scheduled data.
  • the CQIs may be directly from the mobile terminals 16 or determined at the base station 14 based on information provided by the mobile terminals 16. In either case, the CQI for each mobile terminal 16 is a function of the degree to which the channel amplitude (or response) varies across the OFDM frequency band.
  • Scheduled data 44 which is a stream of bits, is scrambled in a manner reducing the peak-to-average power ratio associated with the data using data scrambling logic 46.
  • a cyclic redundancy check (CRC) for the scrambled data is determined and appended to the scrambled data using CRC adding logic 48.
  • channel coding is performed using channel encoder logic 50 to effectively add redundancy to the data to facilitate recovery and error correction at the mobile terminal 16. Again, the channel coding for a particular mobile terminal 16 is based on the CQI. in some implementations, the channel encoder logic 50 uses known Turbo encoding techniques .
  • the encoded data is then processed by rate matching logic 52 to compensate for the data expansion associated with encoding.
  • Bit interleaver logic 54 systematically reorders the bits in the encoded data to minimize the loss of consecutive data bits.
  • the resultant data bits are systematically mapped into corresponding symbols depending on the chosen baseband modulation by mapping logic 56.
  • mapping logic 56 Preferably, Quadrature Amplitude Modulation (QAM) or Quadrature Phase Shift Key [QPSK) modulation is used.
  • QAM Quadrature Amplitude Modulation
  • QPSK Quadrature Phase Shift Key
  • the degree of modulation is preferably chosen based on the CQI for the particular mobile terminal.
  • the symbols may be systematically reordered to further bolster the immunity of the transmitted signal to periodic data loss caused by frequency selective fading using symbol interleaver logic 59.
  • STC encoder logic 60 which modifies the symbols in a fashion making the transmitted signals more resistant to interference and more readily decoded at a mobile terminal 16.
  • the STC encoder logic 60 will process the incoming symbols and provide "n" outputs corresponding to the number of transmit antennas 28 for the bass station 14.
  • the control system 20 and/or baseband processor 22 as described above with respect to Figure 9 will provide a mapping control signal to control STC encoding.
  • the symbols for the ss n" outputs are representative of the data to be transmitted and capable of being recovered by the mobile terminal 16.
  • FIG. 12 illustrate reception of the transmitted signals by a mobile terminal 16.
  • the respective signals are demodulated and amplified by corresponding RF circuitry 70.
  • Analog- to-digital (A/D) converter and down-conversion circuitry 72 digitizes and downconverts the analog signal for digital processing.
  • the resultant digitized signal may be used by automatic gain control circuitry (AGC) 74 to control the gain of the amplifiers in the RP circuitry 70 based on the received signal level.
  • AGC automatic gain control circuitry
  • the processing logic compares the received pilot symbols with the pilot symbols that are expected in certain sub-carriers at certain times to determine a channel response for the sub-carriers in which pilot symbols were transmitted. The results are interpolated to estimate a channel response for most, if not all, of the remaining sub- carriers for which pilot symbols were not provided. The actual and interpolated channel responses are used to estimate an overall channel response, which includes the channel responses for most, if noc all, of the sub-carriers in the OFDM channel.
  • the frequency domain symbols and channel reconstruction information which are derived from the channel responses for each receive path are provided to an STC decoder 100, which provides STC decoding on both received paths to recover the transmitted symbols.
  • the channel reconstruction information provides equalization information to the STC decoder 100 sufficient to remove the effects of the transmission channel when processing the respective frequency domain symbols
  • CRC logic 112 removes the CRC checksum, checks the scrambled data in traditional fashion, and provides it to the de-scrambling logic 114 for de- scrambling using the known base station de-scrambling code to recover the originally transmitted data 116.
  • Figures 8 to 12 each provide a specific example of a communication system or elements of a communication system that could be used to implement embodiments of the invention.
  • a relay may have particular elements found in either the base station or mobile station to enable communication between the bases station and mobile station and or other relay stations. It is to be understood that embodiments of the invention can be implemented with communications systems having architectures that are different than the specific example, but that operate in a manner consistent with the implementation of the embodiments as described herein.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne des procédés et des systèmes destinés à être utilisés avec des réseaux sans fil ayant une ou plusieurs cellules, selon lequel chaque cellule comprend une station de base (BS), au moins une station relais (RS) et au moins une station mobile (MS). La ou les stations relais peuvent être utilisées en tant que station intermédiaire pour transmettre une communication entre la station de base (BS) et la station mobile (MS). L'invention concerne des procédés d'allocation de ressources de multiplexage par répartition orthogonale de la fréquence (OFDM) pour une communication entre la station de base (BS), la station relais (RS) et/ou la station mobile (MS). Dans certains modes de réalisation de l'invention, les procédés sont cohérents et/ou peuvent être utilisés conjointement avec des normes existantes, telles que la norme 802.16e.
PCT/CA2008/000450 2007-03-02 2008-03-03 Procédés et systèmes pour des réseaux sans fil avec des relais WO2008106797A1 (fr)

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WO2010047626A1 (fr) * 2008-10-20 2010-04-29 Telefonaktiebolaget L M Ericsson (Publ) Gestion de qualité de service pour fonction liaison terrestre en lte
US8971263B2 (en) 2008-10-20 2015-03-03 Telefonaktiebolaget L M Ericsson (Publ) QoS management for self-backhauling in LTE
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EP2339891A1 (fr) * 2008-11-07 2011-06-29 Huawei Technologies Co., Ltd. Procédé et noeud de réseau pour transmission par relais
EP2339891A4 (fr) * 2008-11-07 2011-11-23 Huawei Tech Co Ltd Procédé et noeud de réseau pour transmission par relais
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US8472868B2 (en) 2009-05-06 2013-06-25 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for MIMO repeater chains in a wireless communication network
US8521080B2 (en) 2009-09-11 2013-08-27 Sony Corporation Relay station device, base station device, mobile station device, and radio communication system
EP2296420A1 (fr) * 2009-09-11 2011-03-16 Sony Corporation Dispositif de station relais, dispositif de station de base, dispositif de station mobile et système de communication radio
WO2012070045A3 (fr) * 2010-11-24 2012-11-01 Elta Systems Ltd. Procédés de gestion de trafic divers pour réseau cellulaire à raccordement à sauts multiples dynamique et systèmes utiles conjointement avec eux
US10285208B2 (en) 2010-11-24 2019-05-07 Elta Systems Ltd. Various traffic management methods for dynamic multi-hop backhauling cellular network and systems useful in conjunction therewith
US11356168B2 (en) 2010-11-24 2022-06-07 Elta Systems Ltd. Various traffic management methods for dynamic multi-hop backhauling cellular network and systems useful in conjunction therewith

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