U.S. patent application number 16/776628 was filed with the patent office on 2020-05-28 for method and apparatus for a radio node and a controlling gateway.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Suresh Krishnan, Stere Preda, Catherine Truchan.
Application Number | 20200170051 16/776628 |
Document ID | / |
Family ID | 54238625 |
Filed Date | 2020-05-28 |
United States Patent
Application |
20200170051 |
Kind Code |
A1 |
Krishnan; Suresh ; et
al. |
May 28, 2020 |
Method and Apparatus for a Radio Node and a Controlling Gateway
Abstract
In one aspect of the teachings herein, a controlling gateway and
an associated radio access point are configured for operation in a
radio access network and use a radio protocol stack that is split
on the network side between the gateway and the access point, for
conveying radio bearer traffic going between the radio access
network and a wireless device. According to methods and apparatuses
disclosed, the radio protocol entities affected by the stack split
communicate using Internet Protocol, IP, sessions. Advantageously,
the radio bearer traffic conveyed over the split stack maps to
different IP sessions in dependence on any one or more of network
capabilities, various isolation or privacy requirements associated
with the device and/or traffic, the types of data being conveyed,
the types of radio bearers involved, and the involved Radio Link
Control, RLC, operating modes.
Inventors: |
Krishnan; Suresh; (Johns
Creek, GA) ; Preda; Stere; (Longueuil, CA) ;
Truchan; Catherine; (Lorraine, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
54238625 |
Appl. No.: |
16/776628 |
Filed: |
January 30, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16160050 |
Oct 15, 2018 |
10588164 |
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16776628 |
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14783888 |
Oct 12, 2015 |
10129914 |
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PCT/US2015/051226 |
Sep 21, 2015 |
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16160050 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 92/12 20130101;
H04L 69/16 20130101; H04L 2212/00 20130101; H04L 29/08 20130101;
H04W 76/10 20180201; H04W 88/16 20130101 |
International
Class: |
H04W 76/10 20060101
H04W076/10; H04L 29/06 20060101 H04L029/06; H04W 92/12 20060101
H04W092/12; H04L 29/08 20060101 H04L029/08 |
Claims
1. A method of operation in a gateway node that is coupled to a
core network of a wireless communication network, the method
comprising: implementing an upper portion of a radio protocol stack
in the gateway node, the radio protocol stack being used to support
communications with a wireless device having a corresponding radio
protocol stack, wherein a lower, remaining portion of the radio
protocol stack is implemented in a radio node that provides radio
bearers for communicating with the wireless device; and exchanging
Service Data Units (SDUs) between the upper portion of the radio
protocol stack, as implemented in the gateway node, and the lower
portion of the radio protocol stack, as implemented in the radio
node, via an intra-stack IP link.
2. The method of claim 1, wherein the intra-stack IP link comprises
an IP Version 6 (IPv6) link.
3. The method of claim 1, further comprising: for delivering data
to the wireless device via a data radio bearer between the radio
node and the wireless device when the wireless device is operating
in a Radio Link Control (RLC) Unacknowledged Mode (UM),
establishing an IP session over the intra-stack IP link using a
User Datagram Protocol (UDP); for delivering data to the wireless
device via a data radio bearer between the radio node and the
wireless device when the wireless device is operating in a RLC
Acknowledged Mode (AM) or in a RLC Transparent Mode (TM),
establishing an IP session over the intra-stack IP link using a
Transport Control Protocol (TCP); and for transmitting Broadcast
Control Channel (BCCH) or Paging Control Channel (PCCH) signaling
for the wireless device via a signaling radio bearer at the radio
node, establishing an IP session over the inter-stack IP link using
a Transport Security Layer (TLS) protocol.
4. The method of claim 1, wherein the radio protocol stack
includes, in descending layer order, a Radio Resource Control (RRC)
layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio
Link Control (RLC) protocol layer, a Medium Access Control (MAC)
protocol layer, and a Physical (PHY) protocol layer, wherein the
radio protocol stack is split at the RLC and PDCP layers, and
wherein the intra-stack IP link communicatively couples the RLC
layer in the radio node to the PDCP layer in the gateway node.
5. The method of claim 1, wherein the SDUs exchanged via the
intra-stack IP link are exchanged in one or more IP sessions that
are uniquely mapped for the wireless device.
6. A gateway node configured for operation in a wireless
communication network and comprising: a first communication
interface configured for communicating with a radio node to be
controlled by the gateway node; a second communication interface
configured for communicating with one or more core network nodes in
a core network of the wireless communication network; and
processing circuitry operatively associated with the first and
second communication interfaces and configured to: implement an
upper portion of a radio protocol stack in the gateway node, the
radio protocol stack being used to support communications with a
wireless device having a corresponding radio protocol stack,
wherein a lower, remaining portion of the radio protocol stack is
implemented in a radio node that provides radio bearers for
communicating with the wireless device; and exchange Service Data
Units (SDUs) between the upper portion of the radio protocol stack,
as implemented in the gateway node, and the lower portion of the
radio protocol stack, as implemented in the radio node, via an
intra-stack IP link.
7. The gateway of claim 6, wherein the intra-stack IP link
comprises an IP Version 6 (IPv6) link.
8. The gateway node of claim 6, wherein the processing circuitry is
configured to: for delivering data to the wireless device via a
data radio bearer between the radio node and the wireless device
when the wireless device is operating in a Radio Link Control (RLC)
Unacknowledged Mode (UM), establish an IP session over the
intra-stack IP link using a User Datagram Protocol (UDP); for
delivering data to the wireless device via a data radio bearer
between the radio node and the wireless device when the wireless
device is operating in a RLC Acknowledged Mode (AM) or in a RLC
Transparent Mode (TM), establish an IP session over the intra-stack
IP link using a Transport Control Protocol (TCP); and for
transmitting Broadcast Control Channel (BCCH) or Paging Control
Channel (PCCH) signaling for the wireless device via a signaling
radio bearer at the radio node, establish an IP session over the
inter-stack IP link using a Transport Security Layer (TLS)
protocol.
9. The gateway node of claim 6, wherein the radio protocol stack
includes, in descending layer order, a Radio Resource Control (RRC)
layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio
Link Control (RLC) protocol layer, a Medium Access Control (MAC)
protocol layer, and a Physical (PHY) protocol layer, wherein the
radio protocol stack is split at the RLC and PDCP layers, and
wherein the intra-stack IP link communicatively couples the RLC
layer in the radio node to the PDCP layer in the gateway node.
10. The gateway node of claim 6, wherein the SDUs exchanged via the
intra-stack IP link are exchanged in one or more IP sessions that
are uniquely mapped for the wireless device.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/160,050 filed 15 Oct. 2018, which is a continuation of U.S.
application Ser. No. 14/783,888 filed 12 Oct. 2015 and issued as
U.S Pat. No. 10,129,914 B2, which in turn is a U.S. National Phase
Application of PCT/US2015/051226 filed 21 Sep. 2015. The entire
contents of each aforementioned application is incorporated herein
by reference.
TECHNICAL FIELD
[0002] The present invention relates to wireless communication
networks, and particularly relates to a radio node and a gateway
node operating according to a split radio protocol stack.
BACKGROUND
[0003] Increased network density and increased heterogeneity are
among the key factors complicating the design and implementation of
wireless communication networks. Network designers and operators
must balance the necessity of having good coverage, at least in
areas of high use, and having the right type of coverage, e.g.,
high-data rate coverage, against the enormous capital and operating
expenditures needed to deploy and maintain the kind of equipment
needed to ensure that those necessities are being met.
[0004] In one approach to increasing network density, rather than
simply adding more "macro" or large-cell base stations, network
operators are deploying smaller, low-power base stations, or
allowing third-parties, such as individual homeowners or other
subscribers, to deploy such base stations. These base stations
characteristically provide radio coverage in much smaller areas,
e.g., only within the confines of a typical residence or office.
Consequently, these coverage areas are often referred to as "small"
cells.
[0005] The base stations or access points, APs, that provide
small-cell coverage may or may not use the same Radio Access
Technology, RAT, in use in the macro-layer of the network, and
varying degrees of integration are contemplated for APs with
respect to the network at large. For example, the APs may or may
not be part of overall coordinated interference reduction schemes
that coordinate scheduling or other operational aspects of the
network across and between cells.
[0006] Merely by way of example, a network operator may lease or
sell small, low-power APs that individual subscribers install in
their homes or workplaces. These APs may provide better baseline
coverage, or they may act as higher data-rate hotspots and, as
such, they may have broadband connections back to the operator's
network. In a particular approach, the APs couple to the operator's
network through a controlling gateway. In such implementations, the
AP has an air interface for connecting to devices and has one or
more network connections, often "wired" connections, back to the
controlling gateway, which in turn has some type of "backhaul"
connection to the operator's core network.
[0007] The gateway arrangement provides a number of advantages. For
example, one gateway may support more than one AP. Consequently, at
least some of the processing can be consolidated in the gateway.
The centralization of certain Radio Access Network, RAN, processing
functions is a topic of growing interest, and it is envisioned as a
key aspect of future-generation network implementations.
[0008] Broadly, the idea here involves dividing the overall air
interface operations and management processing between the actual
radio access points providing the radio bearers and centralized
processing nodes that provide relatively cheap pools of processing
resources that can be leveraged for potentially large numbers of
radio access points, also referred to generically as "base
stations". The lower-level functions, such as radio resource
allocations and dynamic user scheduling are performed at the radio
access nodes, which provide the actual radio link(s), while at
least some of the higher-layer processing is moved to a central
location.
[0009] This kind of disaggregation of the overall air interface
processing protocols generally involves some "splitting" of the
radio protocol stack between a radio access point and the
centralized processing node. To better appreciate the split stack
approach, consider the radio protocol stack used in Long Term
Evolution or LTE. A wireless communication device and a network
base station configured for operation in accordance with the LTE
air interface each implements a version of the LTE protocol
stack.
[0010] Protocol entities in the device-side stack mirror and
communicate with corresponding peer entities in the network-side
stack. The LTE stack includes a physical or PHS' layer, as its
bottom-most layer, a Medium Access Control, MAC, layer above the
physical layer, a Radio Link Control, RLC, layer above the MAC
layer, a Packet Data Convergence Protocol, PDCP, layer above the
RLC layer, and a Radio Resource Control, RRC, layer above the PDCP
layer. For more details regarding these layers and their functions,
the interested reader may refer to the following Third Generation
Partnership Project, 3GPP, Technical Specifications: TS 36.201 for
a discussion of the physical layer, TS 36.321 for a discussion of
the MAC layer, TS 36.322 for a discussion of the RLC layer, TS
36.323 for a discussion of the PDCP layer, and TS 36.331 for a
discussion of the RRC layer.
[0011] In the context of the aforementioned gateway arrangement, a
residential or other such radio access point implements a portion
of the radio protocol stack on the network side, with the remaining
portion of the stack implemented at the controlling gateway. This
arrangement provides the twofold benefit of simplifying the radio
access point and leveraging the gateway node for supporting more
than one radio access point. However, the protocol endpoints or
peers for the network-side radio protocol stack exist in the
device-side protocol stack, and there are no standardized endpoints
or mechanisms for the split-stack interface between the radio
access point and the controlling gateway.
[0012] It is recognized herein that the split should be transparent
to the overall radio stack protocols and should be managed for link
efficiencies and reliability. Further recognized herein are the
dual needs for scalability and discoverability, e.g., so that
individual connecting gateways can support tens, hundreds or even
greater numbers of radio access points, and so that the involved
inter-split connections can be easily configured between the
involved controlling gateway and its supported radio access
points.
SUMMARY
[0013] In one aspect of the teachings herein, a controlling gateway
and an associated radio access point are configured for operation
in a radio access network and use a radio protocol stack that is
split on the network side between the gateway and the access point,
for conveying radio bearer traffic between the radio access network
and a wireless communication device. According to methods and
apparatuses disclosed, the radio protocol entities affected by the
stack split communicate using Internet Protocol, IP, sessions.
Advantageously, the radio bearer traffic conveyed over the split
stack maps to different IP sessions in dependence on any one or
more of network capabilities, various isolation or privacy
requirements associated with the wireless communication device
and/or traffic, the types of data being conveyed, the types of
radio bearers involved, and the involved Radio Link Control. RLC,
operating modes.
[0014] In one embodiment, a method of operation in a gateway node
that is coupled to a core network of a wireless communication
network includes determining that data is available for sending to
a wireless communication device--also referred to as a "wireless
device" or simply "device"--that accesses the wireless
communication network via a radio cell provided by a radio node
that is coupled to a core network of the wireless communication
network via the gateway node. The method includes generating
service data units corresponding to the data, based on processing
the data according to an upper portion of a radio protocol stack,
where the radio protocol stack is split between the gateway node,
which implements the upper portion of the radio protocol stack, and
the radio node, which implements a remaining, lower portion of the
radio protocol stack. Still further, the method includes
establishing an IP session towards the radio node, via an
intra-stack IP link communicatively coupling the upper portion of
the radio protocol stack at the gateway node with the lower portion
of the radio protocol stack at the radio node.
[0015] The IP session is mapped to a radio bearer to be used for
conveying the data to the wireless device via an air interface of
the radio cell, and the method further includes encapsulating the
service data units in one or more IP packets, according to IP
session parameters associated with the IP session, and sending the
IP packets to the radio node via the IP session, for
de-encapsulation and recovery of the service data units, for
subsequent processing by the radio node according to the remaining,
lower portion of the radio protocol stack. Complementary processing
and configurations also apply in the uplink direction, where data
transmitted by the wireless device is received at the radio node
and processed according to the portion of the protocol stack
implemented at the radio node, and encapsulated for transfer across
the intra-stack IP link. Note that the intra-stack IP link is
transparent to the overall protocol flow going between the wireless
network and the device. In other words, the intra-stack IP link
merely provides a mechanism for conveying data between the protocol
entities that would otherwise not be split if the radio protocol
stack on the network side were consolidated in a single node.
[0016] In another embodiment, a gateway node is configured for
operation in a wireless communication network and includes a first
communication interface that is configured for communicating with a
radio node to be controlled by the gateway node. The gateway node
further includes a second communication interface that is
configured for communicating with one or more core network nodes in
a core network of the wireless communication network. Still
further, the gateway node includes processing circuitry that is
operatively associated with the first and second communication
interfaces.
[0017] The processing circuitry is configured to determine that
data is available for sending to a wireless device that accesses
the wireless communication network via a radio cell provided by the
radio node, where the radio node is coupled to the core network of
the wireless communication network via the gateway node. The
processing circuitry is further configured to generate service data
units corresponding to the data, based on processing the data
according to an upper portion of a radio protocol stack, where the
radio protocol stack is split between the gateway node, which
implements the upper portion of the radio protocol stack, and the
radio node, which implements a remaining, lower portion of the
radio protocol stack. The processing circuitry is further
configured to establish an IP session towards the radio node, via
an intra-stack IP link communicatively coupling the upper portion
of the radio protocol stack at the gateway node with the lower
portion of the radio protocol stack at the radio node. The IP
session is mapped to a radio bearer to be used for conveying the
data to the wireless device via an air interface of the radio cell
and the processing circuitry is additionally configured to
encapsulate the service data units in one or more IP packets,
according to IP session parameters associated with the IP session,
and send the IP packets to the radio node via the IP session, for
de-encapsulation and recovery of the service data units, for
subsequent processing by the radio node according to the remaining,
lower portion of the radio protocol stack. Complementary processing
and configurations also apply in the uplink direction, where data
transmitted by the wireless device is received at the radio node
and processed according to the portion of the protocol stack
implemented at the radio node, and encapsulated for transfer across
the intra-stack IP link.
[0018] In yet another embodiment, a gateway node is configured for
operation in a wireless communication network and includes a first
communication interface that is configured for communicating with a
radio node to be controlled by the gateway node, along with a
second communication interface that is configured for communicating
with one or more core network nodes in a core network of the
wireless communication network. The gateway node further includes
processing circuitry that is operatively associated with the first
and second communication interfaces.
[0019] The processing circuitry is configured to receive an IP
packet from the radio node in an IP session on an intra-stack IP
link that communicatively couples a lower portion of a radio
protocol stack at the radio node to an upper portion of the radio
protocol stack at the gateway node. The radio protocol stack at
issue here a network-side radio protocol stack complementing a
device-side radio protocol stack implemented at the wireless device
that sent the uplink data encapsulated in the received IP packet.
The processing circuitry is further configured to map the IP
session to a radio bearer, according to session-to-bearer mapping
known at the gateway node, and to de-encapsulate a service data
unit contained in the IP packet. The processing circuitry is
configured to input the service data unit into the upper portion of
the radio protocol stack and to send data generated from processing
the service data unit according to the upper portion of the radio
protocol stack to a core network for higher-layer processing.
[0020] In a related embodiment, a method of operation in a gateway
node includes receiving an IP packet from a radio node in an IP
session on an intra-stack IP link that communicatively couples a
lower portion of a radio protocol stack at the radio node to an
upper portion of the radio protocol stack at the gateway node.
Here, the radio node is controlled by the gateway node and provides
a cell for wirelessly connecting wireless devices to the network.
The radio protocol stack in question is a network-side radio
protocol stack complementing a device-side radio protocol stack
implemented at the wireless device that sent uplink data
encapsulated in the IP packet.
[0021] The method further includes mapping the IP session to a
radio bearer, according to session-to-bearer mapping known at the
gateway node, de-encapsulating a service data unit contained in the
IP packet, inputting the service data unit into the upper portion
of the radio protocol stack, and sending the data generated from
processing the service data unit according to the upper portion of
the radio protocol stack to a core network for higher-layer
processing.
[0022] Of course, the present invention is not limited to the above
features and advantages. Indeed, those skilled in the art will
recognize additional features and advantages upon reading the
following detailed description, and upon viewing the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a block diagram of one embodiment of a gateway
node and a radio node controlled by the gateway node, where both
the gateway node and the radio node are configured for operation in
a wireless communication network.
[0024] FIG. 2 is a diagram of a known radio protocol stack, such as
may be advantageously split according to the teachings herein.
[0025] FIG. 3 is a diagram of one embodiment of a split radio
protocol stack as implemented in a split configuration, with an
upper portion of the stack implemented in a gateway node and a
lower portion of the stack implemented in a radio node controlled
by the gateway node.
[0026] FIG. 4 is a diagram of further example details for the split
radio protocol stack of FIG. 3.
[0027] FIG. 5 is a logic flow diagram of one embodiment of a method
of processing at a gateway node controlling a radio node, wherein a
network-side radio protocol stack is split between the gateway node
and the radio node.
[0028] FIG. 6 is a logic flow diagram of one embodiment of a method
of processing at a radio node controlled by a gateway node, wherein
a network-side radio protocol stack is split between the gateway
node and the radio node.
[0029] FIG. 7 is a logic flow diagram of another embodiment of a
method of processing at a radio node controlled by a gateway node,
wherein a network-side radio protocol stack is split between the
gateway node and the radio node.
[0030] FIG. 8 is a logic flow diagram of another embodiment of a
method of processing at a gateway node controlling a radio node,
wherein a network-side radio protocol stack is split between the
gateway node and the radio node.
[0031] FIG. 9 is a block diagram of one embodiment of a gateway
node and a radio node controlled by the gateway node, where both
the gateway node and the radio node are configured for operation in
a Long Term Evolution, LTE, network.
[0032] FIG. 10 is a diagram of the split radio protocol stack,
shown in context with the additional supporting nodes seen in FIG.
9.
[0033] FIG. 11 is a call flow diagram illustrating one embodiment
of signaling between a radio node and customer premises equipment,
CPE, used to couple the radio node to a controlling gateway
node.
[0034] FIG. 12 is a call flow diagram illustrating one embodiment
of signaling between a radio node and a controlling gateway node,
for establishing a secure connection between them.
[0035] FIG. 13 is a call flow diagram illustrating one embodiment
of signaling between a radio node and a controlling gateway node,
for configuring the radio node and setting up an IP session between
the controlling gateway node and the radio node, for coupling the
radio protocol stack split between the gateway and radio nodes.
[0036] FIG. 14 is a logic flow diagram illustrating one embodiment
of downlink packet processing involving a wireless device, a radio
node and a controlling gateway node, where the radio node and the
controlling gateway node use a split radio protocol stack.
DETAILED DESCRIPTION
[0037] FIG. 1 illustrates a wireless communication network 10
configured to provide communication services to any number of
wireless communication devices 12, where only two such devices 12-1
and 12-2 are shown by way of example. Unless suffixes are needed
for clarity, the reference number "12" is used herein, for both
singular and plural reference to any given device, or devices. The
same usage applies with respect to any other "base" reference
number where suffixing is used herein.
[0038] The network 10 communicatively couples the individual
devices 12 to one or more operator, OP, Internet Protocol, IP,
services and/or external networks 14, such as the Internet and may
provide for inter-device communications within the network 10. The
network 10 includes a Radio Access Network, RAN 16, and a Core
Network, CN 18. In this example, the RAN 16 includes a radio node
20 and a gateway node 22. The gateway node 22 is configured to
control the radio node 20 and to provide communicative coupling to
the CN 18. By way of example, the radio node 20 is a home base
station or other small-cell device that provides radio coverage in
a corresponding radio cell or cells 24, which may have a limited
coverage area, such as a low-power cell intended to encompass a
single residence or other structure.
[0039] While only one cell 24 is illustrated, it will be
appreciated that the radio node 20 may provide more than one cell
24, e.g., by using different carrier frequencies, using different
frequency sub-bands, using Time Division Multiplexing, TDM, etc.
Although only one radio node 20 and one gateway node 22 are
illustrated, the network 10 may include any number of radio nodes
20, e.g., each at different locations within a broader geographic
area. Further, the network 10 may include a gateway node 22 for
each such radio node 20, or may have one gateway node 22 for
subsets or groups of radio nodes 20. In one or more embodiments, it
is contemplated to control potentially large numbers of radio nodes
20 via one gateway node 22. Additionally, the network 10 may
include other entities not illustrated or described, as will be
understood by those of ordinary skill in the wireless communication
arts. For example, in one or more non-limiting embodiments, the
network 10 comprises a Long Term Evolution, LTE, or LTE-Advanced
network, configuring according to the applicable technical
specifications promulgated by the Third Generation Partnership
Project, 3GPP. Consequently, the network 10 includes a variety of
nodes or other entities associated with such networks, including
Mobility Management Entities or MMEs in the CN 18, along with a
Packet Data Gateway Nodes or PDGN, providing a packet data
interface between the CN 18 and the external network(s) 14.
[0040] Regardless of whether the radio node 20 is implemented as a
LTE Home eNB, HeNB, or as some other type of radio base station, it
will be understood as comprising a mix of signal processing and
control circuitry, along with supporting radio transceiver
circuitry. In the example illustration, the radio node 20 includes
first and second communication interfaces 30-1 and 30-2--generally
referred to as "communication interfaces 30"--along with processing
circuitry 32 that is operatively associated with the communication
interfaces 30.
[0041] The processing circuitry 32 comprises fixed circuitry,
programmed circuitry, or a combination of fixed and programmed
circuitry. In an example embodiment, the processing circuitry 32 is
at least partly implemented using programmed circuitry and
comprises, for example, one or more processors 34, such as one or
more microprocessors, Digital Signal Processors or DSPs,
Application Specific Integrated Circuits or ASICs, Field
Programmable Gate Arrays or FPGAs, or other digital processing
circuitry. Correspondingly, the processing circuitry 32 includes or
is associated with one or more types of computer-readable
media--"STORAGE 36" in the figure--such as one or more types of
memory circuits such as FLASH, EEPROM, SRAM, DRAM, etc.
Additionally, or alternatively, the storage 36 comprises hard disk
storage, Solid State Disk, SSD, storage, etc.
[0042] In general, the storage 36 provides both working memory and
longer-term storage. In at least one embodiment, the storage 36
provides non-transitory storage for a computer program 38 and one
or more items of configuration data 40. Here, non-transitory does
not necessarily mean permanent or unchanging storage but does means
storage of at least some persistence--i.e., holding information for
subsequent retrieval. The computer program 38, which may comprise a
number of related or supporting programs, comprises program
instructions that, when executed by the one or more processors 34
implement the processing circuitry 32 according to the
configuration examples described herein. In other words, in some
embodiments, one or more general-purpose processing circuits within
the radio node 20 are specially adapted to carry out the teachings
herein, based on their execution of the computer program
instructions comprising the computer program 38.
[0043] However implemented, the radio node 20 is configured to
provide radio coverage in one or more cells 24, and the first
communication interface 30-1 is configured for communicating with
wireless devices 12 operating in any of the one or more cells 24.
For example, the communication interface 30-1 is configured for
transmitting and receiving radiofrequency signals according to the
air interface protocols and signal structure adopted for the air
interface between the radio node 20 and the devices 12. To that
end, the communication interface 30-1 includes one or more
radiofrequency transmitters and receivers, and associated protocol
processing circuitry that is adapted to support the uplink and
downlink air interfaces implemented within the network 10.
[0044] The radio node 20 further includes a second communication
interface 30-2 configured to communicatively couple the radio node
20 to its controlling gateway node 22, which in turn is coupled to
the CN 18. The second communication interface 30-2 may comprise a
wired or wireless interface, e.g., a LAN or microwave-based
interface, and shall be understood as providing physical-layer
circuitry adapted for sending and receiving signals over the
involved transmission medium, along with corresponding circuitry
for protocol processing, as needed for communicating with the
gateway node 22.
[0045] Similarly, the gateway node 22 will be understood as
comprising a mix of signal processing and control circuitry, along
with supporting communication interfaces--i.e., communication
interface circuits. In the example illustration, the gateway node
22 includes first and second communication interfaces 50-1 and
50-2--generally referred to as "communication interfaces 50"--along
with processing circuitry 52 that is operatively associated with
the communication interfaces 50.
[0046] The processing circuitry 52 comprises fixed circuitry,
programmed circuitry, or a combination of fixed and programmed
circuitry. In an example embodiment, the processing circuitry 52 is
at least partly implemented using programmed circuitry and
comprises, for example, one or more processors 54, such as one or
more microprocessors, Digital Signal Processors or DSPs,
Application Specific Integrated Circuits or ASICs, Field
Programmable Gate Arrays or FPGAs, or other digital processing
circuitry. Correspondingly, the processing circuitry 52 includes or
is associated with one or more types of computer-readable
media--"STORAGE 56" in the figure--such as one or more types of
memory circuits such as FLASH, EEPROM, SRAM, DRAM, etc.
Additionally, or alternatively, the storage 56 comprises hard disk
storage, Solid State Disk, SSD, storage, etc.
[0047] In general, the storage 56 provides both working memory and
longer-term storage. In at least one embodiment, the storage 56
provides non-transitory storage for a computer program 58 and one
or more items of configuration data 60. As before, the term
non-transitory does not necessarily mean permanent or unchanging
storage, but does means storage of at least some persistence. The
computer program 58, which may comprise a number of related or
supporting programs, comprises program instructions that, when
executed by the one or more processors 54 implement the processing
circuitry 52 according to the configuration examples described
herein. In other words, in some embodiments, one or more
general-purpose processing circuits within the gateway node 22 are
specially adapted to carry out the teachings herein, based on their
execution of the computer program instructions comprising the
computer program 58.
[0048] However implemented, the first communication interface 50-1
is configured for communicating with the radio node 20, which is
controlled by the gateway node 22, and the second communication
interface 50-2 is configured for communicating with one or more
core network nodes--not individually depicted in FIG. 1--in the CN
18 of the network 10.
[0049] Now consider FIG. 2, which illustrates a known radio
protocol stack used in LTE. It will be appreciated that a
complementary or mirror copy of the illustrated stack is
conventionally implemented in each of the involved protocol
endpoints--e.g., in a wireless device and in its serving base
station. In the context of these teachings, the "network side"
radio protocol stack is split between the radio node 20 and its
controlling gateway node 22.
[0050] FIG. 3 illustrates an example split-stack arrangement. In
the diagram, a radio protocol stack 70 is split. The upper portion
72 of the radio protocol stack 70 resides in the gateway node 22
while a lower portion 74 of the radio protocol stack 70 resides in
the radio node 22.
[0051] In this example, the upper portion 72 includes a Packet Data
Convergence Protocol, PDCP, layer and a Radio Resource Control,
RRC, layer. In the hierarchy of the overall radio protocol stack
70, the PDCP layer is "below" the RRC layer. The lower portion 74
of the radio protocol stack 70 includes a Radio Link Control, RLC,
layer, a Medium Access Control, MAC, protocol layer below the RLC
protocol layer, and a Physical, PHY, protocol layer below the MAC
protocol layer.
[0052] FIG. 4 provides further example details. For example, one
sees that a "PDCP stub" may be implemented in the lower portion 74
of the radio protocol stack 70, to account for the fact that the
illustrated split lies at the RLC-to-PDCP logical interface. The
intra-stack IP link 26/IP session(s) 28 communicatively couple the
RRC and PDCP layers at the gateway node 22 to the RLC protocol
layer at the radio node 20. In particular, one or more IP sessions
28 are used to send SDUs from the RRC/PDCP layers RLC layer to the
RLC layer over the intra-stack IP link 26 in the downlink direction
and vice-versa in the uplink direction.
[0053] Turning back to FIG. 1, the processing circuitry 52 of the
gateway node 22 is operatively associated with the first and second
communication interfaces 50 and is configured to determine that
data is available for sending to a wireless device 12 that accesses
the network 10 via a radio cell 24 provided by the radio node 20,
where the radio node 20 is coupled to the CN 18 of the network 10
via the gateway node 22. The processing circuitry 52 is further
configured to generate service data units corresponding to the
data, based on processing the data according to an upper portion 72
of a radio protocol stack 70. The radio protocol stack 70 is split
between the gateway node 22, which implements the upper portion 72
of the radio protocol stack 70, and the radio node 20, which
implements the lower portion 74 of the radio protocol stack 70.
[0054] Here, it shall be understood that the radio protocol stack
70 is the network-side stack and that the wireless device 12
implements a complementary device-side radio protocol stack having
peer entities corresponding to the protocol entities seen in the
network-side stack 70. Thus, what is at issue here is the split
between portions of the network-side radio protocol stack 70 and
the need for establishing a reliable, efficient, and scalable
mechanism for intra-stack communications between the protocol
entities within the network-side radio protocol stack 70 that are
exposed to the split.
[0055] To that end, the processing circuitry 52 of the gateway node
22 is configured to establish an IP session 28 towards the radio
node 20, via an intra-stack IP link 26 that communicatively couples
the upper portion 72 of the radio protocol stack 70 at the gateway
node 22 with the lower portion 74 of the radio protocol stack 70 at
the radio node 20. Notably, this IP session is distinct from and
transparent to any IP sessions that may be running at the
"applications" layer between the wireless device 12 and an
application server in the OP services/external networks 14. Indeed,
according to the advantageous teachings herein, the IP session 28
is transparent to the end-to-end communications session(s) between
the wireless device 12 and any end-point accesses via the network
10, and is used purely to connect the upper portion 72 of the
network-side radio protocol stack 70 at the gateway node 22 to the
lower portion 74 of the network-side radio protocol stack 70 at the
radio node 20.
[0056] Advantageously, the IP session 28 is mapped to a radio
bearer to be used for conveying the data to the wireless device 12
via an air interface of the radio cell 24, and the processing
circuitry 52 is configured to encapsulate the service data units in
one or more IP packets, according to IP session parameters
associated with the IP session 28, and send the IP packets to the
radio node 20 via the IP session 28, for de-encapsulation and
recovery of the service data units, for subsequent processing by
the radio node 20 according to the remaining, lower portion 74 of
the radio protocol stack 70.
[0057] Complementary processing and functions at the gateway node
22 and at the radio node 20 provide for the transfer of uplink data
and signaling from the wireless device over one or more IP sessions
28 on the intra-stack IP link 26. That is, downlink data towards
the wireless device 12 is processed at the gateway node 22
according to the protocol layers implemented in the upper portion
72 of the radio protocol stack 70, and is encapsulated as IP
traffic for conveyance over an IP session 28 supported via the
intra-stack IP link 26. The radio node 20 receives the encapsulated
data and de-encapsulates it for processing according to the
protocol layers implemented in the lower portion 74 of the radio
protocol stack 70. Conversely, uplink data--traffic or
signaling--from the wireless device 12 is received by the radio
node 20 and processed in the uplink direction according to the
lower portion 74 of the radio protocol stack. The processed data is
sent from the radio node 20 to the gateway node 22 as IP packets in
an IP session 28 on the intra-stack IP link 26. The gateway node 22
extracts the data encapsulated in the IP packets and continues
processing that data in the uplink direction, according to the
protocol layers implemented in the upper portion 72 of the radio
protocol stack 70.
[0058] In at least some embodiments, the processing circuitry 52 is
configured to establish the IP session 28 using a User Datagram
Protocol, UDP, when the radio bearer is a data radio bearer, and
the wireless device 12 is operating in a Radio Link Control, RLC,
Unacknowledged Mode, UM. The processing circuitry 52 is further
configured to establish the IP session 28 using a Transmission
Control Protocol, TCP, when the radio bearer is a data radio bearer
and the wireless device 12 is operating in a RLC Acknowledged Mode,
AM, or in a RLC Transparent Mode, TM. Still further, the processing
circuitry 52 is configured to establish the IP session 28 using a
Transport Layer Security, TLS, protocol, when the radio bearer is a
signaling radio bearer, for transmitting Broadcast Control Channel,
BCCH, or Paging Control Channel, PCCH, signaling. TLS is also used
for SRB0 and SRB1, after AS. Further, in at least some embodiments,
the IP session 28 is mapped uniquely for the radio bearer and the
wireless device 12, or is mapped according to a unique flow label
assigned to the radio bearer, or is mapped to a unique flow label
assigned to the wireless device 12.
[0059] FIG. 5 illustrates a method 500 of operation in a gateway
node 22 that is coupled to a CN 18 of a network 10. By way of
example, FIG. 5 focuses on downlink processing and the method 500
includes determining (Block 502) that data is available for sending
to a wireless device 12 that accesses the wireless communication
network 10 via a radio cell 24 provided by a radio node 20 that is
coupled to the CN 18 of the wireless communication network 10 via
the gateway node 22. The method 500 further includes generating
(Block 504) service data units corresponding to the data, based on
processing the data according to an upper portion 72 of a radio
protocol stack 70, wherein the radio protocol stack 70 is split
between the gateway node 22, which implements the upper portion 72
of the radio protocol stack, and the radio node 20, which
implements a remaining, lower portion 74 of the radio protocol
stack 70.
[0060] Still further, the method 500 includes establishing (Block
506) an IP session 28 towards the radio node 20, via an intra-stack
IP link 26 that communicatively couples the upper portion 72 of the
radio protocol stack 70 at the gateway node 22 with the lower
portion 74 of the radio protocol stack 70 at the radio node 20. The
IP session 28 is mapped to a radio bearer to be used for conveying
the data to the wireless device 12 via an air interface of the
radio cell 24, and the method 500 includes encapsulating (Block
508) the service data units in one or more IP packets, according to
IP session parameters associated with the IP session 28, and
sending (Block 510) the IP packets to the radio node 20 via the IP
session 28, for de-encapsulation and recovery of the service data
units, for subsequent processing by the radio node 20 according to
the remaining, lower portion 74 of the radio protocol stack 70.
[0061] The IP link 26 in one embodiment comprises an IP Version 6,
IPv6, link. Of course, it is also contemplated that the IP link 26
be implemented as an IPv4 link and in operation, the gateway node
22 may support IP sessions 28 based on both IPv4 and IPv6. For
example, a given radio node 20 may not support IPv6, while another
radio node 20 does support IPv6.
[0062] FIG. 6 illustrates a method 600 in a radio node 20,
corresponding to the gateway method 500. The radio node 20 is
configured for operation in the network 10 and is particularly
configured for being controlled by the gateway node 22. The method
600 includes establishing (Block 602) a radio bearer under control
of a gateway node 22, for communicating with a wireless device 12
and establishing (Block 604) an IP session 28 with the gateway node
22, via an intra-stack IP link 26 between the radio node 20 and the
controlling gateway node 22. Again, this IP link 26 is for
connecting the upper and lower portions 72 and 74 of the split
radio protocol stack 70, and should not be confused with end-to-end
IP sessions/links between the wireless device 12 and any
"application" layer servers or systems.
[0063] The method 600 further includes receiving (Block 606) one or
more IP packets via the IP session 28 and de-encapsulating the
received IP packets to recover the data targeted to the wireless
device 12. More particularly, the de-encapsulation involves
de-encapsulating the IP packets to recover the SDUs incoming from
the protocol layer operating in the gateway node 22 at the point
where the radio protocol stack 70 is split between the gateway node
22 and the radio node 20. Correspondingly, the method 600 further
includes inputting (Block 608) the de-encapsulated data into the
remaining, lower-portion 74 of the radio protocol stack 70, as
implemented at the radio node 20, for processing and sending to the
wireless device 12 over the air interface.
[0064] FIGS. 7 and 8 illustrate substantially similar processing as
set forth in FIGS. 5 and 6, but are presented in the context of
uplink processing. In particular, the method 700 of FIG. 7 depicts
radio node processing and includes receiving (Block 702) user
traffic from a wireless device 12. The method 700 further includes
generating (Block 704) SDU(s) from the received user traffic, via
the lower portion 74 of the radio protocol stack 70, and mapping
(Block 706) the radio bearer associated with the SDU(s) to an IP
session 28 on the intra-stack IP link 26. Processing continues with
the radio node 20 encapsulating (Block 708) the SDU(s) into one or
more IP packets, in accordance with the mapped/Identified IP
session 28, and sending (Block 710) the IP packet(s) towards the
gateway node 22 over the intra-stack IP link 26.
[0065] FIG. 8 illustrates a corresponding method 800 as carried out
by the gateway node 22. The method 800 includes receiving (Block
802) an IP packet from the radio node 20 in an IP session 28 on the
intra-stack IP link 26, and mapping (Block 804) the IP session 28
to a radio bearer, according to session/bearer mapping known at the
gateway node 22, e.g., from connection setup/establishment
processing. Processing continues with the gateway node 22
de-encapsulating (Block 806) the SDU(s) contained in the IP packet
and inputting (Block 808) the SDU(s) into the upper portion 72 of
the radio protocol stack. The method 800 continues with the gateway
node 22 sending (Block 810) the data generated from processing the
SDU(s) in the upper portion 72 of the radio protocol stack 70 on to
the core network for higher-layer processing.
[0066] Consequently, it will be appreciated that a SDU output from
the "top" of the lower portion 74 of the radio protocol stack 70 is
encapsulated in an IP packet for transport over the intra-stack IP
link 26, in the IP session 28 to which the involved radio bearer is
mapped. At the gateway node 22, the SDU is extracted from the IP
packet and passed into the "bottom" of the upper portion 72 of the
radio protocol stack 70, for completion of the overall protocol
processing associated with the radio protocol stack 70 in the
uplink direction. The converse is true in the downlink direction,
i.e., SDUs emerging from the bottom of the upper portion 72 of the
radio protocol stack 70 are encapsulated as IP packets and
transported in a mapped IP session 28 over the intra-stack IP link
26. The radio node 20 de-encapsulates those IP packets to recover
the SDUs, which are then input to the top of the lower portion 74
of the radio protocol stack 70, for completion of the overall stack
processing in the downlink direction. It will be appreciated that
the "bottom" of the upper portion 72 is taken as the stack layer at
the gateway node 22 that is exposed to the split. Likewise, the
"top" of the lower portion 74 is taken as the stack layer at the
radio node 20 that is exposed to the split.
[0067] FIG. 9 illustrates an example embodiment in the context of a
LTE network, wherein the CN 18 includes serving gateway, S-GW 80,
coupled to the gateway node 22 via a S1-UE interface, and a MME 82
coupled to the gateway node 22 via a S1-MME interface. The S-GW 80
and MME are communicatively coupled via a S11 interface, and the
S-GW 80 is further communicatively coupled to a Packet Gateway,
P-GW 84, which provides the packet-routing interface, SGi, into and
out of the network 10. The MME 82 communicatively couples to a Home
Subscriber Server, HSS 86, via an S6a interface, and the HSS 86
couples to a Policy and Charging Rules Function, PCRF 88, which is
also coupled to the P-GW 84. In the diagram, dashed connection
lines are used to illustrate Control Plane, CP, signaling, while
solid connection lines are used to illustrate User Plane, UP,
signaling.
[0068] FIG. 10 illustrates an example splitting of the radio
protocol stack 70 between the radio node 20 and the gateway node
22, in the context of the LTE network example of FIG. 9. FIG. 10
illustrates the further supporting protocol stacks used at the
various other CN nodes seen in FIG. 9 and particularly highlights
the IP link 26/IP session 28 used to link the lower portion 74 of
the split radio protocol stack 70, as implemented in the radio node
20, with the upper portion 72 of the stack 70, as implemented in
the gateway node 22. It will be appreciated that there may be any
number of split-stack "instances" implemented between the gateway
node 22 and the radio node 20, e.g., for simultaneously supporting
multiple wireless devices 12.
[0069] With the above example implementation details in mind, it
shall be appreciated that the mapping of radio bearer, RB, traffic,
e.g., PDCP PDUs, to IP sessions 28 provides for flexible
connectivity between a gateway node 22 and any number of controlled
radio nodes 20. The proposed RB-to-IP mapping schemes provide a
scalable solution that supports potentially large numbers of radio
nodes 20 with respect to a controlling gateway node 22.
[0070] Further, the mapping scheme(s) presented herein provide
radio bearer traffic granularity and a sound, robust traffic
isolation solution upon which various network use-cases become more
easily deployable by the network operator. Example use cases
include bearer-based or device-based routing policy deployment, for
efficiently routing device traffic over the IP connection
interconnecting the split stack 70, e.g., using IPv6 flow labels.
Another example is bearer-based and/or device-based access control
security policy deployment, such as where firewalling parameters or
policy settings are based on the identities of the wireless devices
12 being supported via the split-stack arrangement. Further
examples include bearer-based and/or device-based
Quality-of-Server, QoS, policy deployment, data packet inspection
at the gateway node 22 on a per device 12 and a per radio node 20
basis, and lawful interception techniques, which typically requires
per device discrimination.
[0071] The teachings herein further provide for the use of IP
service discovery for dynamic configuration of the radio node 20,
e.g. IPv6 address auto-configuration--stateless address auto
configuration or SLAAC--as well as dynamic discovery of the gateway
node 22 by each radio node 20 to be controlled by the gateway node
22. The teachings herein further provide for the use of Transport
Layer Security, TLS, encryption to secure BCCH, PCCH, SRB0 and SRB1
traffic, which is not PDCP-ciphered. Here, "SRB0" and "SRB1"
denotes Signaling Radio Bearer 0 and Signaling Radio Bearer 1,
respectively. The SRB0 and SRB1 are used for the transfer of RRC
and Non-Access Stratum signaling messages. RRC messages go between
the wireless device 12 and the radio node 20 and NAS messages go
between the wireless device 12 and the MME 82. Still further, the
teachings herein enable the use of TCP for window-based flow
control of RLC traffic in the AM mode.
[0072] In an example implementation, the radio node 20 provides the
RLC/MAC/PHY layers of the radio protocol stack 70, i.e., the lower
portion 74 of the split stack 70 at the radio node 20 includes the
RLC, MAC, and PHY layers. Correspondingly, the gateway node 22
provides centralized RRC and PDCP functions, which are managed by
the involved network operator and are connected to any number of
radio nodes 20. Thus, the gateway node 22 provides centralized
radio resource control for multiple radio nodes 20. The gateway
node 22 further provides the mapping between the GTP-U TEID-to-IP
sessions for Data Radio Bearers, DRBs, as well as the mapping of
RRC contexts-to-IP sessions for Signaling Radio Bearers, SRBs,
based on the information supplied by each such radio node 20.
[0073] In the LTE context and with reference again to FIG. 10, the
Uu and S1 interfaces are unchanged in one or more embodiments
contemplated herein. The changes are limited to the newly proposed
interface between the gateway node 22 and the radio node 20, for
communicatively coupling together the upper portion 72 of the split
radio protocol stack 70 with the lower portion 74 of the split
radio protocol stack 70. This new interface, represented in FIG. 10
as the IP link 26/IP session(s) 28, transports packets between the
protocol entities that are exposed to the split. In LTE, the CP and
UP traffic carried over this new interface. where RRC messages may
be simply forwarded on a "pass-through" basis from RLC entities to
PDCP entities and vice versa. BCCH, PCCH, SRB0 and SRB1 traffic are
sent over the IP link 26 using TLS/TCP/IP. SRB2 and DRBs are PDCP
protected, i.e. encrypted, and, therefore, are sent over the IP
link 26 using TCP or UDP. In one or more embodiments, Stream
Control Transmission Protocol, SCTP, packets are avoided to prevent
blocking issues that might otherwise arise with respect to CPE
firewalling.
[0074] FIG. 11 illustrates an example call flow diagram covering
local network attachment operations, wherein the radio node 20
connects to the local network provided by CPE. The radio node 20
sends router solicitation signaling and receives a return router
advertisement, performs SLAAC processing, and then sends a DHCPv6
information request. The radio node 20 receives a corresponding
response from the CPE that includes the address of the gateway node
22 supporting the radio node 20 and coupling it to the CN 18. Note
that the router advertisement will contain a prefix to
auto-configure an address, e.g., using SLAAC, and will have the 0
bit set to initiate stateless DHCPv6. It is also contemplated to
use a Fully Qualified Domain Name, FQDN, if load balancing and/or
failover of the gateway node 22 are required.
[0075] FIG. 12 illustrates a call flow diagram covering a secure
channel establishment between a radio node 20 and its supporting
gateway node 22. It is contemplated that in at least one embodiment
of such signaling that a client certificate is used to authenticate
the radio node 20 towards the network 10. A TLS connection may be
used for sending unencrypted control and data plane traffic over
the IP link 26/IP session 28.
[0076] FIG. 13 illustrates a call flow diagram covering processing
that follows the establishment of a secure connection between a
radio node 20 and its supporting gateway node 22. After
establishing a secure channel, the radio node 20 connects to the
gateway node 22 to initiate configuration. The gateway node 22 will
then provide the radio initialization parameters, such as radio
frequency bands, bandwidth, access schemes, antenna technology,
physical channel configurations, etc., for the radio node 20. After
receiving the radio parameters, the radio node 20 sends the set of
mappings between each radio bearer and the IP address plus the port
and/or IPv6 flow label combination that it will use for traffic on
that specific bearer, with respect to the IP link 26.
[0077] Although it may be assumed that IPv6 links are used to
transport data between the radio node 20 and the gateway node 22
for the IP link 26 supporting the stack split, the first mapping
scheme presented below is also applicable to IPv4 links. It is
assumed that there is a single PDU per IP packet, and all messages
are sent in network byte order. All contemplated schemes consider
UDP for bearers configured in RLC UM mode and TCP for RLC AM and
TM.
[0078] In a first mapping option contemplated herein, there is a
unique IP session 28 per bearer and per wireless device 12. That
is, there is an IP session 28 on the IP link 26 for each bearer
with respect to each wireless device 12 being supported by the
radio node 20.
[0079] In a second mapping option contemplated herein, there is a
unique IPv6 flow label per bearer type. As compared to the first
mapping scheme, the difference is that flow isolation is achieved
by using a different IPv6 flow label per radio bearer type. This
second scheme allows for improved packet switching based on flow
label or bearer type.
[0080] In a third mapping option, there is a unique IPv6 flow label
per wireless device 12. As compared to the second mapping scheme,
the difference with this third mapping scheme is that flow
isolation is achieved by using a different IPv6 flow label per
wireless device 12, which is identified with a C-RNTI-like ID. If
the flow labels are exchanged on demand, for example, upon initial
attachment of a wireless device 12 to the radio node 20, the IPv6
flow labels could embed the C-RNTI of the attaching wireless device
12.
[0081] FIG. 14 is a logic flow diagram illustrating another
embodiment of a method 1400 of processing at a gateway node 22 that
is configured for operation in a network 10, and for controlling a
radio node 20 that is configured to communicatively couple one or
more wireless devices 12 to the network 10 via a cell 24 provided
by the radio node 20. The method 1400 focuses on a downlink example
and begins with receiving a packet at the gateway node 22 for a
given wireless device 12 (Block 1402). Processing continues with
identifying the radio bearer or radio bearer type to be used for
conveying the received packet (Block 1404). If the received packet
is user traffic, it is associated with a DRB and processing
continues in Block 1406, with performing Robust Header Compression,
ROHC, and ciphering at the PDCP layer of the radio protocol stack
70. Here, the PDCP layer resides in the gateway node 22.
[0082] The involved DRB is mapped to an IP session 28 (Block 1408)
that provides the intra-stack connection between the split entities
of radio protocol stack 70, and the RLC mode is determined (Block
1410). For AM mode operation, the method 1400 includes checking
whether a connection to the wireless device 12 has been established
(Block 1412) and performing connection setup (Block 1414) if not.
Once the connection has been setup, or if the RLC mode is UM,
processing continues with encapsulating (Block 1416) the received
user-traffic packet in an IP packet for conveyance (Block 1418) to
the radio node 20 via the IP session 28 supported by the IP link 26
that interconnects the lower portion 74 of the split radio protocol
stack 70 in the radio node 20 with the upper portion 72 of the
split radio protocol stack 70 in the gateway node 22.
[0083] That is, the encapsulation occurs here for purposes of
conveying the packet between the split entities of the radio
protocol stack 70, as split between the gateway node 22 and the
radio node 20, and is unrelated to any IP running at protocol
layers above the split radio protocol stack 70. It will also be
appreciated that a corresponding de-encapsulation, therefore,
occurs within the lower portion 74 of the radio protocol stack 70
at the radio node 20. Thus, this usage of IP conveyance is
transparent to higher-layer protocol endpoints running at the
wireless device 12 and, e.g., at the P-GW 84 or at some server
external to the network 10, and is operative only with respect to
interconnecting the entities within the radio protocol stack 70
that are exposed to the split between the radio node 20 and the
gateway node 22.
[0084] On the other hand, with reference again to Block 1404, if
the received packet is BCCH, PCCH, or otherwise associated with
SRB0, SRB1 or SRB2 control signaling, RRC processing is performed
at Block 1420 and, for SRB1 signaling, processing includes
determining whether AS Security--a LTE security protocol associated
with RRC signaling--is active (Block 1422). If AS Security is not
active, it is contemplated herein to advantageously apply TLS, and
processing in this case thus continues with RB-to-IP-Session
mapping (Block 1428), for the IP link 26, and TLS encryption of the
received packet (Block 1430). TLS could be used for the duration of
the SRB1 traffic, but switching after AS is another option. For
SRB2 signaling, or in the case where AS Security is active, the
PDCP layer processing includes encryption of the packet, and thus
processing can continue from Block 1420 or Block 1422 with PDCP
processing (Block 1424) and RB-to-IP-Session mapping for the IP
link 26 (Block 1426).
[0085] From Block 1426, processing continues with determining
whether a connection to the wireless device 12 has been established
(Block 1432) and, if so, performing IP encapsulation of the packet
for conveyance over the IP link 26 in the mapped IP session 28
(Blocks 1434 and 1436). If the connection has not already been
setup, the connection is setup at Block 1438 (NO from Block 1432),
and then the encapsulation and conveyance operations in Blocks 1434
and 1436 are carried out.
[0086] Notably, modifications and other embodiments of the
disclosed invention(s) will come to mind to one skilled in the art
having the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the invention(s) is/are not to be limited to the
specific embodiments disclosed and that modifications and other
embodiments are intended to be included within the scope of this
disclosure. Although specific terms may be employed herein, they
are used in a generic and descriptive sense only and not for
purposes of limitation.
* * * * *