BACKGROUND

The following relates generally to wireless communication, and more specifically to autonomous formation for backhaul networks.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system, or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

In some cases, a UE may experience poor communication with a network access device, and the network access device may configure the UE to connect to, and route communications through, one or more relays (e.g., which may be another UE, a network operator-deployed relay). A data routing path between a UE and a Donor eNodeB (DeNB) may include a single relay node (RN) that is transparent to the UE. In some cases, however, it may be desirable for a data routing path to contain multiple such relays. The rollout of such highly densified networks may create a backhaul issue in the absence of wireless backhauling. Accordingly, techniques directed to multi-hop wireless backhaul networks (e.g., such that the data routing path between the UE and donor contains multiple relays) may be desired. For example, such multi-hop wireless backhauling may be important for the rollout of millimeter wave (mmW) access technologies (e.g., because the limited range of mmW-based communications may result in highly densified, small-cell deployments). For the support of wireless backhauling, it may be desirable to enable new relays to autonomously attach to already-integrated relays (e.g., by reusing existing packet data network (PDN) connectivity establishment procedures, and thereby obtaining network connectivity (e.g., data network (DN) connectivity) to the donor).

SUMMARY

Techniques are described whereby the communication range of a wireless device may be extended through the use of multiple relays, which may autonomously form a wireless backhaul network. Such autonomously formed wireless backhaul networks may be beneficial for communications systems that support transmissions over frequency bands that experience large degrees of signal attenuation or systems that would otherwise benefit from the expanded coverage offered by relay techniques. Additionally, these wireless backhaul networks may provide cost-efficient alternatives (or supplements) to infrastructure-based wired relay solutions. Sequential (e.g., recursive) implementations are considered such that the size of the wireless backhaul network may scale efficiently. In some examples, the wireless backhaul network may be formed by reusing existing connectivity establishment procedures. Importantly, the proposed techniques enable a relay to possess (e.g., be configured with) functionality that may traditionally be associated with a user equipment (UE), base station (BS), and gateway (GW). Such multi-faceted functionality may enable the described sequential formation of wireless backhaul networks with tree topology.

A method of wireless communication is described. The method may include establishing a first connection to a first data network (DN) via a wireless link with a network node, receiving, from a second relay, a packet data unit (PDU) session request, forwarding the PDU session request to a network management function, identifying a DN address for the second relay, establishing a second connection to a second DN for the second relay, and connecting the second relay to the first DN by routing data from the first DN to the second DN based on the identified DN address.

An apparatus for wireless communication is described. The apparatus may include means for establishing a first connection to a first DN via a wireless link with a network node, means for receiving, from a relay (e.g., a second relay), a PDU session request, means for forwarding the PDU session request to a network management function, means for identifying a DN address for the relay (e.g., the second relay), means for establishing a second connection to a second DN for the relay (e.g., the second relay), and means for connecting the relay (e.g., the second relay) to the first DN by routing data from the first DN to the second DN based on the identified DN address.

Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to establish a first connection to a first DN via a wireless link with a network node, receive, from a relay (e.g., a second relay), a PDU session request, forward the PDU session request to a network management function, identify a DN address for the relay (e.g., the second relay), establish a second connection to a second DN for the relay (e.g., the second relay), and connect the relay (e.g., the second relay) to the first DN by routing data from the first DN to the second DN based on the identified DN address.

A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to establish a first connection to a first DN via a wireless link with a network node, receive, from a relay (e.g., a second relay), a PDU session request, forward the PDU session request to a network management function, identify a DN address for the relay (e.g., the second relay), establish a second connection to a second DN for the relay (e.g., the second relay), and connect the relay (e.g., the second relay) to the first DN by routing data from the first DN to the second DN based on the identified DN address.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the network management function resides on at least one of the network node, a core network (CN), a radio access network (RAN) node, a donor node, or an anchor node.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, forwarding the PDU session request includes including a gateway address of the first relay in the PDU session request. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for forwarding the PDU session request on the first connection.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, at least one of the first DN or the second DN may be one of a packet data network (PDN), an Internet Protocol (IP) network, a local area network (LAN), a backhaul network, a self-backhaul network, or a wireless multi-hop network.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the first DN and the second DN may be both one of a PDN, an IP network, a LAN, a backhaul network, a self-backhaul network, or a wireless multi-hop network.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network management function, a request to establish a gateway function for the second relay.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for forwarding the data from the network node to the second relay by exchanging the data between the first connection to the first DN and the second connection to the second DN.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, establishing the second connection to the second DN for the second relay includes configuring at least one data radio bearer (DRB) between the first relay and the second relay. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for forwarding data received from the network node to the at least one DRB based on the identified DN address.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for establishing a mapping between the at least one DRB and the identified DN address for the second relay. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating a forwarding information base (FIB) based on the mapping.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the mapping may be based on a correlation identifier (ID) associated with the second relay.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, identifying the DN address includes receiving, from the network management function, a DN address prefix. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the method further comprising determining the DN address for the second relay based on the DN address prefix. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting the DN address to the second relay.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the DN address includes a second DN address prefix.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating a FIB at the first relay based on the determined DN address.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the determined DN address includes a DN address of a set of DN addresses determined based on the DN address prefix.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the identified DN address may be preconfigured or determined via a pseudo-random function.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the DN address may be determined based on a stateless address autoconfiguration (SLAAC).

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, identifying the DN address includes transmitting, to the network node, a DN address request for the second relay based on the PDU session request. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving a DN address response based on the DN address request, where the DN address response indicates the DN address for the second relay.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the DN address request indicates a requested DN address for the second relay.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating a FIB at the first relay based on the DN address for the second relay.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, identifying the DN address includes determining the DN address for the second relay based on the PDU session request. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting, to the network node, an indication of the determined DN address for the second relay.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, establishing the second connection to the second DN includes receiving a first non-access stratum (NAS) message from the second relay, the first NAS message indicating the PDU session request. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for forwarding the first NAS message to the network management function.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, a packet indicating the DN address for the second relay. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting the packet to the second relay.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, an address management message indicating a DN address management scheme, where identifying the DN address may be based on the DN address management scheme.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, an address management message indicating a FIB update scheme. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating a FIB based on the FIB update scheme.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for exchanging one or more signaling messages between the network management function and the second relay.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining packet forwarding rules based on the PDU session request forwarded from the second relay to the network management function.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, establishing the first connection to the first DN includes transmitting, to the network node, a radio resource control (RRC) connection request message. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, an RRC response message.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, a response to the PDU session request, where the response includes a Create Session Request message.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for identifying the DN address for the second relay may be based on the Create Session Request message.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining a correlation identifier (ID) for the second relay based on the Create Session Request message.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting, to the network node, a Create Session Response message indicating the correlation ID. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving, from the network node, a setup request based on the Create Session Response message.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the PDU session request indicates a network name.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the DN address may include an address for an IP network, an 802.1 LAN, or a PDN.

