U.S. patent number 9,271,183 [Application Number 14/147,083] was granted by the patent office on 2016-02-23 for managing access channel resources by buffering service requests.
This patent grant is currently assigned to Sprint Spectrum L.P.. The grantee listed for this patent is Sprint Spectrum L.P.. Invention is credited to Siddharth S. Oroskar, Maulik K. Shah, Jasinder P. Singh.
United States Patent |
9,271,183 |
Oroskar , et al. |
February 23, 2016 |
Managing access channel resources by buffering service requests
Abstract
A method for managing access channel traffic during congested
network conditions is disclosed. A wireless connection device (WCD)
sends a service request to a particular base station for a
particular quantity of network resources. Upon the particular base
station determining that it is too loaded with network traffic to
accommodate the service request, the base station saves an
indication of the WCD's connection request, and responds with a
communication to instruct the WCD to idle and wait for a page from
the base station. The WCD, upon receiving the communication, does
not send a service request for a greater quantity of network
resources than the particular quantity until the WCD receives a
page. Once the base station determines it has sufficient network
resources to allocate to the WCD, the base station sends a page to
the WCD, which causes the WCD to send another service request.
Inventors: |
Oroskar; Siddharth S. (Overland
Park, KS), Shah; Maulik K. (Overland Park, KS), Singh;
Jasinder P. (Olathe, KS) |
Applicant: |
Name |
City |
State |
Country |
Type |
Sprint Spectrum L.P. |
Overland Park |
KS |
US |
|
|
Assignee: |
Sprint Spectrum L.P. (Overland
Park, KS)
|
Family
ID: |
55314838 |
Appl.
No.: |
14/147,083 |
Filed: |
January 3, 2014 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
72/1252 (20130101); H04W 74/06 (20130101) |
Current International
Class: |
H04W
28/02 (20090101); H04W 72/04 (20090101); H04W
72/12 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
WO20111160287A1 (with Machine Translation),Yijun Yu, Methods and
Devices for Controlling Congestion, Jun. 22, 2010, p. 6+. cited by
examiner .
LTE Quick Reference, Retry Test / Negative Test / Reject Test,
http://www.sharetechnote.com/html/Handbook.sub.--LTE.sub.--RetryTest.html
(retrieved Nov. 2013), 4 pages. cited by applicant .
Rach, http://www.sharetechnote.com/html/RACH.sub.--LTE.html
(retrieved Nov. 2013), 24 pages. cited by applicant .
Chris Johnson, Long Term Evolution (LTE) in Bullets 2nd Edition,
26.1 RRC Connection Establishment, available at
http://lte-bullets.com/LTE%20in%20Bullets%20-%20RRC%20Connection%20Establ-
ishment.pdf (retrieved Nov. 2013), 5 pages. cited by applicant
.
Chris Johnson, Long Term Evolution (LTE) in Bullets, 23.1 RRC
Connection Establishment, available at
http://lte-bullets.com/LTE%20in%20Bullets%20-%20RRC%20Establishment.pdf
(retrieved Nov. 2013), 4 pages. cited by applicant .
Freescale Semiconductor, Inc. "Long Term Evolution Protocol
Overview", Oct. 2008, 21 pages. cited by applicant.
|
Primary Examiner: Wong; Warner
Claims
We claim:
1. A method of operating a wireless network system, wherein the
wireless network system includes a base station operating to serve
wireless communication devices (WCDs) via one or more scheduled
channels and an unscheduled access channel, wherein the base
station is configured to allocate available network resources
amongst the WCDs by scheduling network traffic over the scheduled
channels so as to accommodate respective demands of the WCDs
indicated, at least in part, by respective service requests
received from the WCDs, the method comprising: receiving a first
service request from a particular WCD, wherein the first service
request specifies a particular quantity of network resources;
responsive to receiving the first service request, making a first
determination that a capacity of available network resources on the
scheduled channels is insufficient to allocate the particular
quantity of network resources to the particular WCD; and responsive
to making the first determination, the base station: (i) sending a
wait-for-page communication to the particular WCD, wherein the
wait-for-page communication causes the particular WCD to, prior to
being paged, forgo transmitting to the base station over the access
channel for the purpose of initiating a service request specifying
a greater quantity of network resources than the particular
quantity of network resources, wherein prior to sending the
wait-for-page communication, determining a quantity of available
network resources on the scheduled channels and wherein the
wait-for-page communication includes an indication of the
determined quantity of available network resources so as to further
cause the particular WCD to, prior to being paged, forgo
transmitting to the base station over the access channel for the
purpose of initiating a service request specifying a greater
quantity of network resources than the determined quantity of
available network resources; (ii) storing data indicative of the
received service request in a memory; (iii) waiting for the
capacity of available network resources on the scheduled channels
to increase; and (iv) responsive to waiting, sending a page to the
particular WCD.
2. The method of claim 1, further comprising: responsive to sending
the page to the particular WCD, receiving a second service request
from the particular WCD, wherein the second service request is
initiated by an unscheduled transmission over the access channel
from the particular WCD to the base station; and responsive to
receiving the second service request, allocating network resources
on the scheduled channels for the particular WCD and sending the
particular WCD a schedule of the allocated network resources.
3. The method of claim 2, wherein the base station schedules the
available network resources of the scheduled channels in resource
blocks that each span a non-overlapping time-frequency segment of
an available spectrum on the scheduled channels; and wherein
allocating network resources on the scheduled channels for the
particular WCD comprises: (i) determining a quantity of resource
blocks sufficient to accommodate the second service request, and
(ii) reserving the determined quantity of resource blocks for the
particular WCD.
4. The method of claim 1, wherein the wait-for-page communication
further causes the particular WCD to forgo transmitting to the base
station over the access channel prior to the particular WCD
receiving the page message.
5. The method of claim 1, and wherein a given WCD that does not
have allocated network resources on the scheduled channels with
which to communicate to the base station is configured to initiate
a connection with the base station by sending an unscheduled
transmission to the base station over the access channel, and
wherein each of the WCDs served by the base station is configured
to operate alternately: in a connected mode, in which the WCD
communicates with the base station using network resources, on the
scheduled channels, that are allocated by the base station, and in
an idle mode, in which the WCD monitors predetermined channels for
pages and does not have allocated network resources on the
scheduled channels, the method further comprising: prior to
receiving the first service request: (i) receiving, via the access
channel, an unscheduled transmission from the particular WCD; (ii)
sending the particular WCD a connection setup communication that
causes the particular WCD to transition to connected mode; and
wherein the wait-for-page communication further causes the
particular WCD to transition to idle mode.
6. The method of claim 1, further comprising: comparing the
capacity of available network resources on the scheduled channels
with the particular quantity of network resources specified by the
first service request; and basing the first determination, at least
in part, on the comparison of the capacity of available network
resources and the quantity of network resources specified by the
first service request.
7. The method of claim 1, wherein waiting for the capacity of
available network resources on the scheduled channels to increase
comprises: at least once, (i) monitoring the capacity of available
network resources on the scheduled channels, (ii) comparing the
monitored capacity to the particular quantity of network resources
specified by the first service request, and (iii) determining,
based on the comparison, whether the monitored capacity exceeds the
particular quantity of network resources; and wherein sending the
page message is performed responsive to determining that the
monitored capacity exceeds the particular quantity of network
resources.
8. The method of claim 1, further comprising: the base station
receiving a plurality of additional service requests, each at a
respective reception time from a respective WCD, wherein each of
the additional service requests specifies a respective quantity of
network resources; sending respective wait-for-page communications
to the respective WCDs so as to cause each of the WCDs to, prior to
being paged, forgo transmitting to the base station over the access
channel for the purpose of initiating a service request specifying
a greater quantity of network resources than the respective
quantity of network resources; storing an indication of the
additional service requests in the memory such that each of the
additional service requests is associated with its order of
reception at the base station; and sending pages to the respective
WCDs in the order in which their associated service requests are
received at the base station, such that each given page is sent to
a given WCD responsive to determining that the capacity of
available network resources on the scheduled channels is sufficient
to accommodate the service request from the given WCD.
9. A method of operating a wireless communication device (WCD) in a
wireless network system, wherein the wireless network system
includes a base station operating to serve a plurality of WCDs
including the WCD via one or more scheduled channels and an
unscheduled access channel, wherein the base station is configured
to allocate available network resources amongst the WCDs by
scheduling network traffic over the scheduled channels so as to
accommodate respective demands of the WCDs indicated, at least in
part, by respective service requests received from the WCDs, the
method comprising: sending a first service request from the WCD to
the base station, wherein the first service request specifies a
particular quantity of network resources; responsive to sending the
first service request, receiving a wait-for-page communication from
the base station; responsive to receiving the wait-for-page
communication, the WCD, prior to being paged, forgoing transmitting
to the base station over the access channel for the purpose of
initiating a service request specifying a greater quantity of
network resources than the particular quantity of network
resources; receiving a page from the base station; and responsive
to receiving the page, sending a second service request to the base
station, wherein the second service requests is initiated by the
WCD sending an unscheduled transmission over the access channel to
the base station.
10. The method of claim 9, further comprising, responsive to
receiving the wait-for-page communication, and prior to receiving
the page, the WCD further forgoing all transmitting to the base
station over the access channel.
11. The method of claim 9, wherein the wait-for-page communication
includes an indication of a quantity of available network
resources, the method further comprising: responsive to receiving
the wait-for-page communication, and prior to receiving the page,
the WCD further forgoing transmitting to the base station over the
access channel for the purpose of initiating a service request
specifying a greater quantity of network resources than the
indicated quantity of available network resources.
12. The method of claim 9, wherein a given WCD that does not have
allocated network resources on the scheduled channels with which to
communicate to the base station is configured to initiate a
connection with the base station by sending an unscheduled
transmission to the base station over the access channel; and
wherein the WCD is configured to operate alternately: in a
connected mode, in which the WCD communicates with the base station
using network resources, on the scheduled channels, that are
allocated by the base station, and in an idle mode, in which the
WCD monitors predetermined channels for page messages and does not
have allocated network resources on the scheduled channels, the
method further comprising: prior to sending the first service
request, the WCD: (i) while in idle mode, sending, via the access
channel, an unscheduled transmission to the base station; (ii)
responsive to sending the unscheduled transmission, receiving a
connection setup communication from the base station; and (iii)
responsive to receiving the connection setup message, transitioning
from idle mode to connected mode; and responsive to receiving the
wait-for-page communication, transitioning to idle mode.
13. The method of claim 9, further comprising: responsive to
sending the second service request, receiving a schedule of
allocated network resources.
14. A wireless network system comprising: a base station having one
or more antenna structures configured to wirelessly communicate
with wireless communication devices (WCDs) served by the base
station over one or more scheduled channels and over an unscheduled
access channel, wherein the base station is configured to allocate
available network resources amongst the WCDs by scheduling network
traffic over the scheduled channels so as to accommodate respective
demands of the WCDs indicated, at least in part, by respective
service requests received from the WCDs, and wherein a given WCD
that does not have allocated network resources on the scheduled
channels with which to communicate to the base station is
configured to initiate a connection with the base station by
sending an unscheduled transmission to the base station over the
access channel; and a controller operatively coupled to the antenna
structures of the base station, wherein the controller is
configured to: (i) receive, at the base station, a first service
request from a particular WCD, wherein the first service request
specifies a particular quantity of network resources; (ii)
responsive to receiving the first connection request, make a first
determination that a capacity of available network resources on the
scheduled channels is insufficient to allocate the particular
quantity of network resources to the particular WCD; and (iii)
responsive to making the first determination: (a) send a
wait-for-page communication to the particular WCD, wherein the
wait-for-page communication causes the particular WCD to, prior to
being paged, forgo transmitting to the base station over the access
channel for the purpose of initiating a service request specifying
a greater quantity of network resources than the particular
quantity of network resources, wherein prior to sending the
wait-for-page communication, determine a quantity of available
network resources on the scheduled channels, and include, in the
wait-for-page communication, an indication of determined quantity
of available network resources so as to further cause the
particular WCD to, prior to being paged, forgo transmitting to the
base station over the access channel for the purpose of initiating
a service request specifying a greater quantity of network
resources than the determined quantity of available network
resources; (b) store data indicative of the received service
request in a memory; (c) wait for the capacity of available network
resources on the scheduled channels to increase; and (d) responsive
to waiting, send a page to the particular WCD.
15. The wireless network system of claim 14, wherein the controller
is further configured to: responsive to sending the page to the
particular WCD, receive a second service request from the
particular WCD, wherein the second service request is initiated by
an unscheduled transmission over the access channel from the
particular WCD to the base station; and responsive to receiving the
second service request, allocate network resources on the scheduled
channels for the particular WCD and send the particular WCD a
schedule of the allocated network resources.
16. The wireless network system of claim 15, wherein the controller
is further configured to: schedule the available network resources
of the scheduled channels in resource blocks that each span a
non-overlapping time-frequency segment of an available spectrum on
the scheduled channels; and allocate network resources on the
scheduled channels for the particular WCD by: (i) determining a
quantity of resource blocks sufficient to accommodate the second
service request, and (ii) reserving the determined quantity of
resource blocks for the particular WCD.
17. The wireless network system of claim 14, wherein each of the
WCDs served by the base station is configured to operate
alternately: in a connected mode, in which the WCD communicates
with the base station using network resources, on the scheduled
channels, that are allocated by the base station, and in an idle
mode, in which the WCD monitors predetermined channels for pages
and does not have allocated network resources on the scheduled
channels, wherein the controller is further configured to, prior to
receiving the first service request: (i) receive, via the access
channel, an unscheduled transmission from the particular WCD; and
(ii) send the particular WCD a connection setup communication that
causes the particular WCD to transition to connected mode; and
wherein the wait-for-page communication further causes the
particular WCD to transition to idle mode.
18. The wireless network system of claim 14, wherein the controller
is further configured to: (i) receive, at the base station, a
plurality of additional service requests, each at a respective
reception time from a respective WCD, wherein each of the
additional service requests specifies a respective quantity of
network resources; (ii) send respective wait-for-page
communications to the respective WCDs so as to cause each of the
WCDs to, prior to being paged, forgo transmitting to the base
station over the access channel for the purpose of initiating a
service request specifying a greater quantity of network resources
than the respective quantity of network resources; (iii) store an
indication of the additional service requests in the memory such
that each of the additional service requests is associated with its
order of reception at the base station; and (iv) send pages to the
respective WCDs in the order in which their associated service
requests are received at the base station, such that each given
page is sent to a given WCD responsive to determining that the
capacity of available network resources on the scheduled channels
is sufficient to accommodate the service request from the given
WCD.
Description
BACKGROUND
Unless otherwise indicated herein, the materials described in this
section are not prior art to the claims and are not admitted to be
prior art by inclusion in this section.
A typical cellular wireless network system (wireless communication
system) may include a number of base stations with antennas that
radiate to define wireless coverage areas, such as cells and cell
sectors. Within the wireless coverage areas, a subscriber (or user)
accesses the communication services via a wireless communication
device (WCD), which can communicate by exchanging radio frequency
signals with the base stations. WCDs may include cell phones,
tablet computers, tracking devices, embedded wireless modules, and
other wirelessly equipped communication devices. In turn, each base
station may be coupled with network infrastructure that provides
connectivity with one or more communication networks, such as the
public switched telephone network (PSTN) and/or a wide area network
(WAN) for sending and receiving packet data (the internet, for
instance). These (and possibly other) elements function
collectively to form a Radio Access Network (RAN) of the wireless
communication system. With this arrangement, a WCD within coverage
of the RAN may communicate with various remote network
entities.
In general, communications on the RAN are carried out in accordance
with an air interface protocol that provides procedures for
coordinating communications between the base stations and the WCDs.
Examples of existing air interface protocols include, without
limitation, Code Division Multiple Access (CDMA) (e.g., 1xRTT and
1xEV-DO), Long Term Evolution (LTE), Wireless Interoperability for
Microwave Access (WiMAX), Global System for Mobile Communications
(GSM), among other examples. Each protocol may define its own
procedures for registration of WCDs, initiation of communications,
handoff between coverage areas, and other functions related to air
interface communication.
Protocols may also define procedures for managing communications
from the base stations to the WCDs, which is referred to as an
downlink, and for managing communications from the WCDs to the base
stations, which is referred to as an uplink.
Depending on the specific underlying technologies and architecture
of a given wireless communication system, the RAN elements may also
take different forms. In a CDMA system configured to operate
according IS-2000 and IS-856 standards, for example, the antenna
system is referred to as a base transceiver system (BTS), and is
usually under the control of a base station controller (BSC). In a
universal mobile telecommunications system (UMTS) configured to
operate according to LTE standards, the base station is usually
referred to as an eNodeB, and the entity that typically coordinates
functionality between multiple eNodeBs is usually referred to as a
mobility management entity (MME). In a CDMA system the WCD may be
referred to as an access terminal (AT); in an LTE system the WCD
may be referred to as user equipment (UE). Other architectures and
operational configurations of a RAN are possible as well.
In accordance with the air interface protocol, each coverage area
may operate on one or more carrier frequencies (or "carriers") and
may define a number of air interface channels for conveying
information between the base stations and the WCDs. These channels
may be defined in various ways, such as through frequency division
multiplexing, time division multiplexing, and/or code-division
multiplexing for instance.
By way of example, each coverage area may have a pilot channel,
reference channel or other resource on which the base station may
broadcast a pilot signal, reference signal, or other resource WCDs
may detect as an indication of coverage and may measure to evaluate
coverage strength. As another example, each coverage area may use
an access channel, an uplink control channel, or other resource on
which WCDs may transmit control messages such as connection
requests and registration requests to the base station. And each
coverage area may use a downlink control channel or other resource
on which the base station may transmit control messages such as
system information messages and page messages to WCDs. Each
coverage area may then have one or more traffic channels or other
resource for carrying communication traffic such as voice data,
packet data, and/or other data between the base station and
WCDs.
Furthermore, the available spectrum on the air interface can be
divided into time-frequency segments to define the various
channels, and also for allocation and scheduling purposes. In an
LTE system, such time-frequency segments are commonly referred to
as resource blocks and span 0.5 milliseconds in time and 180
kilohertz in bandwidth. For example, the base station can evaluate
the demands for network resources amongst its served WCDs and then
allocate its available resources to those WCDs to accommodate those
demands to the extent sufficient resources are available. The
control channels may be used to communicate between the WCDs and
the base station to facilitate evaluation of the various network
demands and also to notify the WCDs of their assigned network
resources once resources are allocated.
While communications are generally scheduled by the base station,
initiation of communication from a WCD to a base station generally
involves at least one unscheduled transmission from the WCD to the
base station. In accordance with the air interface protocol, the
base stations may provide for a shared access channel on which
unscheduled messages can be sent from WCDs to the base station to
notify the base station of the WCD's presence in the base station's
coverage area (e.g., for registration purposes). Once such an
initial unscheduled transmission is received, the base station can
then allocate initial uplink and/or downlink resources to
communicate with the WCD as necessary to manage further
communications. In particular, the WCD may use the initial uplink
resources to send information regarding the quantity of network
resources sought by the WCD. Such a communication from the WCD is
referred to as a service request. The base station can then
allocate sufficient network resources to accommodate the service
request and send an indication of the allocation to the WCD.
However, in some cases a base station is too loaded with existing
network traffic to allocate the resources sought by a WCD. In that
case, after receiving an initial communication from the WCD over
the access channel, the base station may respond by rejecting the
WCD's attempt to connect. After receiving an indication of the base
station's rejection, the WCD may then wait for some period before
attempting another connection. In practice, after receiving an
initial communication over the access channel, the base station may
first allocate some initial control channel resources to receive
further information from the WCD regarding the nature of the
connection sought by the WCD, such as a service request. The base
station can then, on the basis of that information, determine
whether the base station's network resources are sufficient to
accommodate the WCD and respond accordingly.
The access procedure described above, in which an unscheduled
transmission is sent over the access channel, is used when a WCD
does not already have any network resources, and therefore no means
to send an uplink communication to the base station. In practice,
this occurs primarily in two circumstances. First, the WCD may have
data to transmit over the network, such as occurs when a call or
internet session is originated on the WCD and the WCD begins
buffering data to send out. Second, the network may receive data to
communicate to the WCD, such as occurs when a remote entity
initiates a call or other packet data communication addressed to
the WCD. In the first case, the WCD may initiate the access
procedure on its own in response to having data to send out. In the
second case, the network first notifies the WCD that it should
initiate the access procedure by sending the WCD a page message
addressed to the WCD. Upon receiving the page message, the WCD
initiates the access procedure to establish a connection with the
network, at which point the data is delivered to the WCD.
As a result, WCDs without ongoing connections to the network
continue to monitor particular downlink control channels that are
used by the network to send out page messages. As used herein, WCDs
with allocated network resources for ongoing communications are
said to be operating in "connected mode." Connected WCDs are able
to exchange data with remote entities over the network. On the
other hand, WCDs without allocated network resources for ongoing
communications are said to be operating in "idle mode." Idle WCDs
monitor downlink control channels for pages and other system
information, but do not generally transmit uplink communications
back, which also results in reduced power consumption. To conserve
network resources, WCDs may generally be configured to default to
operating in idle mode, and transition to connected mode when data
is ready to transmit or in response to receipt of a page message.
Then, following a period of inactivity, the WCD can transition back
to idle mode.
OVERVIEW
Disclosed herein is a process and corresponding system to manage
communications over an access channel during loaded conditions.
During a basic access procedure, if a base station is loaded with
network traffic at the time it receives a service request, the base
station may reject the service request and respond to the
originating WCD to indicate the request was rejected. The
communication indicating rejection may then cause the WCD to
restart the access procedure and send another service request,
perhaps after some delay. In the event the base station is still
congested when the next service request arrives, the base station
sends another rejection, and the WCD again initiates the access
procedure and sends yet another service request. The cycle repeats
until the base station has enough network resources to grant the
service request. In the interim, the repeated unsuccessful attempts
to employ the access procedure results in increased traffic on the
access channel. Because the communications on the access channel
are generally unscheduled, elevated traffic levels on the access
channel exacerbates the possibility of interference between
transmissions from separate WCDs.
The process disclosed herein avoids such repeated unsuccessful
access channel communications during loaded conditions. According
to the present disclosure, a base station that determines it is too
loaded to accommodate a service request responds by instructing the
originating WCD to idle and wait for a page message before
submitting a service request for equal or greater network resources
than sought by the initial service request. Such a communication
from the base station is referred to herein as a "wait-for-page"
message. The WCD, upon receiving a wait-for-page communication,
operates in idle mode and does not send an additional service
request for an equal or greater quantity of network resources than
sought initially. In effect then, the wait-for-page communication
causes the WCD to forgo unscheduled transmissions on the access
channel if the purpose of such transmissions is to submit a service
request for an equal or greater quantity of network resources than
sought by the initial service request.
After receiving the wait-for-page communication, and prior to
receiving a page message, the WCD effectively acts as though it has
been informed that the base station does not have enough network
resources to grant service requests seeking an equal or greater
quantity of network resources than the initial service request.
Although the WCD may still be allowed to undergo the access
procedure and to submit a service request for a quantity of network
resources less than the quantity sought by the initial service
request.
While the WCD idles and waits for a page message, the base station
saves an indication of the service request and monitors its
available network resources while waiting for an increase in
available network resources. Upon determining that the available
network resources have increased such that sufficient resources are
available to accommodate the saved service request, the base
station then sends a page message to the WCD to override the
effects of the earlier wait-for-page communication. To facilitate
such determinations, the base station may save, for each service
request, an indication of a quantity of network resources sought by
the service request. For instance, the base station may save an
indication of a quality of service, a quantity of data, a desired
latency, minimum bit rate, and/or other parameter(s) related to the
quantity of network resources requested by a given service request.
The base station can then use the saved data to make a subsequent
determination that its available network resources are able to
accommodate the service request saved in memory, and send a page
message to the originating WCD.
After receiving the page message, the WCD initiates a connection
with the base station (e.g., using an unscheduled transmission on
the access channel) and submits another service request. The base
station then grants the service request by allocating the requested
network resources to the WCD. In addition, the base station
coordinates with other network components to establish links to
carry communications between the WCD and various remote networks in
communication with the network. With the network links established,
and resources allocated on the air interface, the WCD operates in
connected mode to exchange data with remote entities over the
network.
In some cases, a base station may maintain a buffer of service
requests from different WCDs, and can page each WCD in the order in
which the original service requests were received. For example,
while loaded, the base station can save data indicative of each
received service request. The saved data for each service request
may include indications of the quantity of network resources
requested, an identifier for the originating WCD, and the time of
reception of the service request. The base station may then
consider each saved service request, in the order of reception, and
upon having sufficient resources to grant a next service request,
send a page message to the corresponding WCD so as to cause that
WCD to connect to the base station. As a result, the base station
may page the WCDs in order, which helps to equalize the latency
associated with establishing connections among different WCDs. By
contrast, in a basic arrangement, previously rejected WCDs might
successfully establish connections based only on whichever WCD
happens to submit a connection request immediately following an
increase in available network resources.
Accordingly, in one respect, disclosed is a method of operating a
wireless network system. The wireless network system can include a
base station operating to serve wireless communication devices
(WCDs) via one or more scheduled channels and an unscheduled access
channel. The base station can be configured to allocate available
network resources amongst the WCDs by scheduling network traffic
over the scheduled channels so as to accommodate respective demands
of the WCDs indicated, at least in part, by respective service
requests received from the WCDs. And a given WCD that does not have
allocated network resources on the scheduled channels with which to
communicate to the base station can be configured to initiate a
connection with the base station by sending an unscheduled
transmission to the base station over the access channel. The
method can include receiving a first service request from a
particular WCD. The first service request can specify a particular
quantity of network resources. The method can include making a
first determination that a capacity of available network resources
on the scheduled channels is insufficient to allocate the
particular quantity of network resources to the particular WCD
responsive to receiving the first service request. The method can
include, responsive to making the first determination, the base
station: (i) sending a wait-for-page communication to the
particular WCD, wherein the wait-for-page communication causes the
particular WCD to, prior to being paged, forgo transmitting to the
base station over the access channel for the purpose of initiating
a service request specifying a greater quantity of network
resources than the particular quantity of network resources; (ii)
storing data indicative of the received service request in a
memory; (iii) waiting for the capacity of available network
resources on the scheduled channels to increase; (iv) after waiting
for the capacity of available network resources on the scheduled
channels to increase, making a second determination that the
capacity of available network resources on the scheduled channels
is sufficient to allocate the particular quantity of network
resources to the particular WCD; and (v) responsive to making the
second determination, sending a page to the particular WCD.
In another respect, disclosed is a method of operating a wireless
communication device (WCD) in a wireless network system. The
wireless network system can include a base station operating to
serve a plurality of WCDs including the WCD via one or more
scheduled channels and an unscheduled access channel. The base
station can be configured to allocate available network resources
amongst the WCDs by scheduling network traffic over the scheduled
channels so as to accommodate respective demands of the WCDs
indicated, at least in part, by respective service requests
received from the WCDs. And a given WCD that does not have
allocated network resources on the scheduled channels with which to
communicate to the base station can be configured to initiate a
connection with the base station by sending an unscheduled
transmission to the base station over the access channel. The
method can include sending a first service request from the WCD to
the base station. The first service request can specify a
particular quantity of network resources. The method can include
receiving a wait-for-page communication from the base station
responsive to sending the first service request. The method can
include, the WCD, responsive to receiving the wait-for-page
communication and prior to being paged, forgoing transmitting to
the base station over the access channel for the purpose of
initiating a service request specifying a greater quantity of
network resources than the particular quantity of network
resources. The method can include receiving a page from the base
station. The method can include sending a second service request to
the base station responsive to receiving the page. The second
service requests can be initiated by the WCD sending an unscheduled
transmission over the access channel to the base station.
In another respect, disclosed is a wireless network system
including a base station and a controller. The base station can
have one or more antenna structures configured to wirelessly
communicate with wireless communication devices (WCDs) served by
the base station over one or more scheduled channels and over an
unscheduled access channel. The base station can be configured to
allocate available network resources amongst the WCDs by scheduling
network traffic over the scheduled channels so as to accommodate
respective demands of the WCDs indicated, at least in part, by
respective service requests received from the WCDs. And a given WCD
that does not have allocated network resources on the scheduled
channels with which to communicate to the base station can be
configured to initiate a connection with the base station by
sending an unscheduled transmission to the base station over the
access channel. The controller can be operatively coupled to the
antenna structures of the base station. The controller can be
configured to receive, at the base station, a first service request
from a particular WCD. The first service request can specify a
particular quantity of network resources. The controller can be
configured to, responsive to receiving the first connection
request, make a first determination that a capacity of available
network resources on the scheduled channels is insufficient to
allocate the particular quantity of network resources to the
particular WCD. The controller can be configured to, responsive to
making the first determination: (i) send a wait-for-page
communication to the particular WCD, wherein the wait-for-page
communication causes the particular WCD to, prior to being paged,
forgo transmitting to the base station over the access channel for
the purpose of initiating a service request specifying a greater
quantity of network resources than the particular quantity of
network resources; (ii) store data indicative of the received
service request in a memory; (iii) wait for the capacity of
available network resources on the scheduled channels to increase;
(iv) after waiting for the capacity of available network resources
on the scheduled channels to increase, make a second determination
that the capacity of available network resources on the scheduled
channels is sufficient to allocate the particular quantity of
network resources to the particular WCD; and (v) responsive to
making the second determination, send a page to the particular
WCD.
Moreover, particular implementations of the present disclosure may
include other examples for saving service requests, and/or other
communications that involve unscheduled transmissions over an
access channel, including wireless communications systems other
than LTE systems.
These as well as other aspects, advantages, and alternatives will
become apparent to those of ordinary skill in the art by reading
the following detailed description, with reference where
appropriate to the accompanying drawings. Further, it should be
understood that the description provided in this overview section
and elsewhere in this document is provided by way of example
only.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a simplified block diagram of an example wireless
communication system in which the present disclosure can be
implemented.
FIG. 1B is a simplified block diagram of an example LTE system in
which the present disclosure can be implemented.
FIG. 2 is a signal flow diagram illustrating signaling between
network nodes that occurs when buffering a service request in an
LTE system.
FIG. 3 is a flow chart depicting functions that can be carried out
by a base station in a radio access network in accordance with an
example method.
FIG. 4 is another flow chart depicting functions that can be
carried out by a wireless communication device in accordance with
an example method.
FIG. 5 is a simplified block diagram of a network node arranged to
carry out various functions in accordance with the present
disclosure.
DETAILED DESCRIPTION
Together with the drawings, the foregoing description provides an
example wireless communication systems in which the present
disclosure can be implemented. It should be understood, however,
that this and other arrangements described herein are set forth
only as examples. As such, those skilled in the art will appreciate
that other arrangements and elements (e.g., machines, interfaces,
functions, orders, and groupings of functions, etc.) can be used
instead, and that some elements may be omitted altogether. Further,
many of the elements described herein are functional entities that
may be implemented as discrete or distributed components or in
conjunction with other components, and in any suitable combination
and location. Various functions described herein as being performed
by one or more entities may be carried out by hardware, firmware,
and/or software. For instance, various functions may be carried out
by a processor executing instructions stored in memory.
I. Example Communication System Architecture
FIG. 1A depicts an example communication system that includes a
radio access network (RAN) 12 having a representative base station
14 and supporting network infrastructure 16. The base station 14
includes antennas arranged to communicate with WCDs 18 in a
coverage area over an air interface 20. RAN 12 then provides
connectivity with one or more transport networks 22, such as the
PSTN or the Internet for instance. With this arrangement, each WCD
18 that is in range of the base station 14 (i.e., in its coverage
area) may register or attach with the RAN 12 and may engage in air
interface communication with the base station 14 so as to
communicate in turn with various remote entities on the transport
network(s) 22 and/or with other WCDs served by the RAN 12.
In this arrangement, the air interface 20 may be configured
according to a particular protocol, and the WCDs 18 and base
station 14 may be programmed or otherwise configured to operate
according to that protocol. According to the air interface
protocol, the network resources provided by the air interface 20
may define time-frequency segments that divide the available
spectrum for communications over the air interface 20. The base
station 14 (alone or in coordination with supporting infrastructure
16 in the RAN 12) may allocate resources to the WCDs 18 in
accordance with an allocation/scheduling routine based on various
factors so as to accommodate the respective communication demands
of the WCDs 18 and/or to achieve network performance criteria. The
base station 14 can then provide each WCD with an indication of the
schedule for their respective network resources, and the WCDs with
allocated resources can then use their respective resources to
exchange bearer data and control communications as necessary.
But a WCD without allocated resources for uplink communications
initiates contact with the base station 14 by sending an
unscheduled transmission over a shared access channel designated by
the RAN 12. The unscheduled transmission may be used to initiate an
access procedure, for example. Once the initial transmission is
received, the base station 14 may assign initial resources for
further communications between the WCD 18 and the base station 14.
For example, the initial resources may be used for the WCD 18 to
send the base station 14 a service request that specifies a
particular quality of service (e.g., by specifying a minimum bit
rate, latency, or another parameter) or otherwise designates a
quantity of network resources sought by the WCD 18. Upon receiving
the WCD's service request, the base station 14 may then determine
whether to grant the service request, which determination may be
based on whether the base station 14 has enough available network
resources to accommodate the service request (e.g., to allocate the
quantity of network resources sought by the service request).
According to the present disclosure, if the base station 14
determines it is too loaded by network traffic to grant the service
request, the base station 14 can send a "wait-for-page" message to
the WCD 18. The wait-for-page communication can cause the WCD 18 to
transition to idle mode and to forgo further service requests for
an equal or greater quantity of network resources until the WCD 18
receives a page message from the base station 14. While the WCD 18
waits, the base station 14 can save an indication of the service
request, then wait for the base station's available network
resources to increase. The saved indication of the service request
may include, for example, data indicating the identity of the WCD
18 and the quantity of network resources sought.
After saving the service request, the base station 14 can monitor
the increase in its available network resources and determine when
its resources become sufficient to accommodate the saved service
request. Upon determining the saved service request can be
accommodated, the base station 14 can send a page message to the
WCD 18. The page message overrides the effect of the earlier
wait-for-page communication. Accordingly, the WCD 18 can then
submit another service request to the base station 14, which
involves another unscheduled transmission on the access channel.
Because the second service request is sent in response to the base
station 14 determining it has sufficient network resources
available, the base station 14 is generally able to grant the
second service request from the WCD 18, at which point the base
station 14 can serve the WCD 18 in connected mode to facilitate
further communications as necessary.
By contrast, as noted above, some protocols cause the base station
14 to send a rejection when the base station 14 is too congested to
allocate resources. The rejection causes the WCD 18 to retry the
random access procedure after some delay, at which point the base
station 14 may still be too congested to allocate resources, which
leads to repeated failed attempts to initiate connections using the
access channel and exacerbates interference between the unscheduled
transmissions. Thus, the presently disclosed enhancements, which
allow for saving a service request until resources become available
and then paging the WCD, obviates the unnecessary communications
over the access channel while the base station 14 is loaded.
FIG. 1A generally represents any wireless communication system in
which the present disclosure can be implemented, and, as noted
above, variations on the arrangement shown are possible. To help
illustrate features of the present disclosure, the remainder of
this document will focus on an LTE system by way of example. Those
of ordinary skill in the art will readily appreciate, however, that
the disclosed principles can be applied as well in other types of
wireless communication systems in which connections are initiated
using unscheduled transmissions from WCDs over an access channel,
with variations where appropriate.
Example LTE Communication System
Accordingly, FIG. 1B is a simplified block diagram of a
representative LTE system as an example of the system shown in FIG.
1A. As shown in FIG. 1B, the LTE system includes an LTE RAN 24 that
primarily serves WCDs 18 with wireless packet data communication
service (but may also provide voice call service, such as
voice-over-IP service or circuit-switched fallback service). The
LTE RAN 24 is shown including a representative LTE base station 26
known as an eNodeB, a gateway system 28 including a serving gateway
(SGW) 30 and a packet data network (PDN) gateway (PGW) 32, and a
mobility management entity (MME) 34.
In practice, the eNodeB 26 includes an antenna structure and
associated equipment for engaging in LTE communication over an LTE
air interface 36 with WCDs 18 to thereby provide the LTE RAN 24
with connectivity to the WCDs 18. The gateway system 28 provides
the LTE RAN 24 with connectivity to packet-switched network(s) 40
such as the Internet and/or private networks. The various network
elements in the LTE RAN 24 are linked together to facilitate
communications between the served WCDs 18 and the remote
packet-switched network 40. The eNodeB 26 communicates with the SGW
30 over an S1-U interface, the eNodeB 26 communicates with the MME
34 over an S1-MME interface, and the MME 34 communicates with the
SGW 30 over an S11 interface. Although each of these interfaces is
shown as a direct link in FIG. 1B, in practice the various elements
of the LTE RAN 24 may sit as nodes on a wireless service provider's
core packet network, and so these and other interfaces described
herein may instead be logical connections over that packet
network.
With this network arrangement, when a WCD 18 enters into coverage
of eNodeB 26, the WCD 18 may scan for system information broadcast
by the eNodeB 26. The WCD 18 can then use the system information to
register or "attach" with the LTE RAN 24 by transmitting an attach
request to the eNodeB 26, which the eNodeB 26 forwards to the MME
34. The MME 34 and other network elements may then carry out
various functions to enable the LTE RAN 24 to serve the WCD 18.
Among other functions, the MME 34 may add the WCD 18 to a database
of registered WCDs managed by the MME 34, such as a home subscriber
server (HSS)
The MME 34 may also communicate with the gateway system 28 and with
the eNodeB 26 to setup and manage one or more bearer connections
extending between the WCD 18 and the PGW 32 and thus between the
WCD 18 and the packet-switched network 40. For instance, for each
such bearer connection, the MME 34 may create and store in data
storage a context record defining an evolved packet system (EPS)
bearer identity for the WCD 18. The MME 34 may generate and
transmit to the SGW 30 a create-session request identifying the
serving eNodeB 26, which triggers setup of a tunnel between the SGW
30 and PGW 32 and assignment of an IP address for the WCD 18. In
this process, the PGW 32 may also establish and store a context
record for the WCD 18 and may assign an IP address to the WCD 18,
and the PGW 32 may signal the assigned IP address in response to
the SGW 30. The SGW 30 may then transmit to the MME 34 a
create-session response specifying the assigned IP address.
Upon receipt of a create-session response from the SGW 30, the MME
34 may then further generate and transmit to the eNodeB 26 an
attach-accept message identifying the SGW 30 and specifying the
assigned IP address, which may trigger setup of a tunnel between
the eNodeB 26 and the SGW 30 and assignment of a corresponding
radio bearer identity defining a tunnel between the WCD 18 and the
eNodeB 26. And the eNodeB 26 may forward to the WCD 18 an
indication of the assigned IP address. Through this process, a
bearer would thus be established between the WCD 18 and the PGW 32,
including a series of tunnels extending (i) between the WCD 18 and
the eNodeB 26, (ii) between the eNodeB 26 and the SGW 30, and (iii)
between the SGW 30 and the PGW 32, and the WCD 18 would have an
assigned IP address that it can use for communication on the
packet-switched network 40. With each such bearer established, the
eNodeB 26 may then serve the WCD 18 in connected mode in which the
eNodeB 26 manages communications to and from the WCD 18 by
allocating and scheduling resources for such communications.
Network Resource Allocation
As noted above, the LTE air interface 36 may span a particular
segment of spectrum, with a given carrier frequency and bandwidth.
The available spectrum may be subdivided into time-frequency
segments referred to as resource blocks (RBs). For example, the RBs
may each span 0.5 millisecond timeslot and have a bandwidth of 180
kHz. That is, during each 0.5 millisecond timeslot, the air
interface may define a number of 180 kHz RBs. In practice, these
RBs may be numbered sequentially across the bandwidth, and groups
of the RBs may define RB groups that may be numbered as well.
Overhead system information broadcast by the eNodeB 26 may inform
the WCDs 18 in the coverage area which RB and RB groups are defined
on the air interface. The WCDs can then use that information to
understand RB assignments keyed to RB number and RB group number
and otherwise to determine which RBs to use to send and receive
data.
The eNodeB 26 (alone or in combination with MME 34 or other network
infrastructure) may manage assignment of RBs for the WCD to use in
receiving communications from the eNodeB 26 (i.e., downlink
communications). For example, when a WCD 18 has data to transmit to
the eNodeB 26 (i.e., uplink communications), the WCD 18 may
transmit to the eNodeB 26 a service request for an assignment of
uplink resources on the air interface 36. The service request may
specify a quantity of data ready to be transmitted from the WCD 18,
such as in a buffer status report. The service request may also
specify a quality of service for the connection (e.g., a quality of
service class identifier (QCI)), or may specify other aspects of
the uplink assignment sought, such as target bit rate or latency,
for instance. Additionally or alternatively, the service request
may specify a particular bearer type for the air interface 36, such
as in cases where the various RBs available for allocation are
grouped to define different bearer types that may be used to carry
different types of communications, for example, guaranteed bit-rate
communications and non-guaranteed bit-rate communications and the
like.
The eNodeB 26 may then perform a scheduling process in which the
eNodeB 26 determines how many RBs to assign for uplink transmission
to provide the requested type and/or quantity of data transmission
requested by the WCD 18. In one approach, upon receiving a service
request, the eNodeB 26 refers to a schedule of RBs in upcoming
timeslot(s), and the eNodeB 26 assigns to the WCD 18 a number of
RBs from those timeslot(s) as necessary and available. The eNodeB
26 may then transmit to the WCD 18 a control message (downlink
control information) specifying the assigned RBs by RB number or RB
group number, or otherwise indicating the schedule of network
resources allocated to the WCD 18. In some cases, semi-persistent
scheduling is employed such that a given allocation provides
resources with a given quality level on an ongoing basis until the
allocation is changed. Semi-persistent scheduling can thereby
reduce the number of control messages used to indicate assigned
resources.
Upon receipt of an assignment of RBs, the WCD 18 may then transmit
some or all of the data that prompted the initial service request
as IP packets using the assigned RBs. Each packet bears the WCD's
assigned IP address as source address and an appropriate IP address
as destination address. Upon receipt of the packets, the eNodeB 26
may then forward the packets using an appropriate tunnel to the
gateway system 28 for transmission by the PGW 32 to the
packet-switched network 40, at which point the packets are routed
according to their respective destination addresses.
Similar to the allocation of uplink resources, the eNodeB 26 (alone
or in combination with associated network infrastructure) may
manage assignment of RBs for the WCD 18 to receive communications
from the eNodeB 26 (i.e., downlink communications). For example,
when the LTE RAN 24 has data to communicate to the WCD 18 (e.g.,
due to a remote-initiated phone call, incoming email, etc. reaching
the gateway system 28), the eNodeB 26 may assign one or more
upcoming RBs on the downlink for use by the WCD 18. The eNodeB 26
can then inform the WCD 18 of the assigned RBs and transmit the
data to the WCD 18 using the assigned RBs.
WCD Operation Modes
Once the WCD 18 is registered with the eNodeB 26, the WCD 18 can
then operate in an idle mode in which the WCD 18 monitors a
downlink control channel to receive overhead information and to
check for any page messages pertinent to the WCD 18. While in idle
mode, the WCD 18 is generally not engaged in ongoing communication
using the LTE RAN 24. To conserve network resources while the WCD
18 is in idle mode, the WCD 18 may not sustain a continuous
connection with the eNodeB 26, and may instead "wake up" as needed
to activate its radio and monitor for relevant communications over
the downlink control channel. Accordingly, the downlink control
channel may be configured to facilitate discontinuous transmission
from the eNodeB 26. Generally, while in the idle mode, the WCD 18
does not have allocated uplink resources with which to send
communications back to the eNodeB 26.
To engage in communication using the RAN, the WCD 18 first
transitions to a connected mode, active mode, or other mode in
which the eNodeB 26 allocates network resources for the WCD 18 to
use. When the LTE RAN 24 has a communication (such as a voice call
or other traffic) to provide to a WCD 18 that is registered with
the network but is operating in the idle mode, the network may page
the WCD 18 in an effort to facilitate assigning traffic channel
resources to use to deliver the data to the WCD 18. The WCD 18
receives the page message, and initiates connection with the eNodeB
26. The eNodeB 26 and/or other network entities may then establish
links between the eNodeB 26 and other network entities to carry
communications to and from the WCD 18 over the LTE RAN 24. The
eNodeB 26 also assigns resources on the air interface 36, and thus
transitions the WCD 18 to a connected mode in which the WCD 18 can
engage in communication with remote entities on the packet-switched
network 40.
Likewise, when the WCD 18 is idle and seeks to initiate (or
originate) a communication (such as to place a voice call or engage
in other bearer communication), the WCD 18 may initiate connection
with the eNodeB 26 and send a request for a desired quantity of
network resources to the eNodeB 26. Links for carrying bearer data
to and from the WCD 18 can then be established by the network, and
the eNodeB 26 can assign network resources to the WCD 18 for use to
carry communications over the air interface 36, similarly
transitioning the WCD 18 to a connected mode in which the WCD 18
can engage in ongoing communication over the LTE RAN 24.
The eNodeB 26 (and/or other components in the LTE RAN 24) can also
cause the WCD 18 to transition from connected mode back to idle
mode. For example, following a period of inactivity by the WCD 18,
the network can send the WCD 18 a release message, which causes the
network to tear down the network links established for the WCD 18,
and to cease allocating resources to the WCD 18. After returning to
idle mode, the WCD 18 continues to monitor downlink control
channels for page messages and system information, but does not
have resources allocated for sending messages back to the
network.
To track the various WCDs in connected/idle modes associated with a
given eNodeB, the MME 34 may assign a state to each WCD within its
tracking network to reflect the current status of the WCDs as
operating in connected mode or operating in idle mode. Based on the
states associated with each WCD, the LTE RAN 24 then allocates
resources to particular WCDs on an ongoing basis. At the same time,
the individual WCDs may also have a state parameter that reflects
the current state of the WCDs and determines the behavior of the
WCDs. When transitioning between modes, the values of the state
parameters maintained by the individual WCDs and the MME 34 can be
adjusted so as to agree with one another. Although, in general, one
state parameter may shift before the other depending on the manner
in which the transition is initiated.
Random Access Procedure
While communications to and from the WCD 18 are generally scheduled
by the eNodeB 26 as noted above, initiation of communication from
the WCD 18 to the eNodeB 26 generally involves at least one
unscheduled transmission from the WCD 18 to the base station 26. In
particular, while the WCD 18 is in idle mode, the WCD 18 generally
does not have resources allocated for sending an uplink
communication. In the LTE RAN 24, the idle WCD 18 may initiate a
connection with the eNode B 26 using a contention-based random
access procedure. The procedure involves contention between
competing WCDs, because unscheduled transmissions from different
WCDs may interfere with one another, given that the eNodeB 26 does
not coordinate/schedule those transmissions. Two interfering WCDs
are then said to be in contention for the attention of the eNodeB
26, and the process to determine which of the two WCDs (if any) is
successful is referred to as resolving the contention.
The random access procedure begins with the eNodeB 26 broadcasting
system information that specifies its physical random access
channel (PRACH) for carrying unscheduled transmissions. For
example, the system information may designate time-frequency
windows (e.g., RBs) designated for PRACH transmissions as well as
other network information (e.g., network capabilities,
synchronization information, etc.) The unscheduled transmissions
can each include a preamble code to differentiate transmissions
received in the same time-frequency window. WCDs in the base
station's coverage area detect the system information broadcast,
randomly select a preamble code, and send a message using the
selected preamble code to the base station over PRACH, which
message is referred to as a preamble message. The preamble codes
are configured such that the eNodeB 26 is able to use code
differentiation to resolve preamble messages with different
preamble codes. But, because the preamble codes are independently
randomly selected by the WCDs 18, it is possible for multiple WCDs
to select the same preamble code, in which case the messages
interfere with one another and result in the previously noted
contention. If one of the interfering preamble messages is stronger
than the others, the eNodeB 26 may be able to successfully decode
the message with the strongest signal despite the increased noise
from the others. But if none of the interfering preamble messages
are significantly stronger than the others, the eNodeB 26 may fail
to decode any of them.
The eNodeB 26 receives the preamble message over PRACH and responds
with a random access response (RAR) during a response window that
is based on the time-frequency window used to send the initial
preamble message. As a result, all WCDs that sent preamble messages
during a given time-frequency window monitor the same response
window. A given RAR may therefore include data addressed to each of
the preamble codes received in the preceding PRACH time-frequency
window. For example, the RAR may include indicators for each of the
preamble codes the eNodeB 26 received, and the WCD(s) that used
those codes for their preamble messages then use the indicators to
identify the data addressed to them. If a given WCD does not
identify an indicator corresponding to the preamble code used by
that WCD (such as may occur if the preamble message could not be
decoded by the eNodeB due to interference or otherwise), the WCD
restarts the random access procedure by selecting a new preamble
code and transmitting another preamble message over PRACH.
For a WCD that does identify an indicator corresponding to their
selected preamble code in the RAR, the data addressed to the WCD
may include an assignment of initial control channel uplink and
downlink resources to allow the WCD to exchange further information
with the eNodeB 26. In addition, the RAR can assign a temporary
cell radio network temporary identifier (temporary C-RNTI) to
identify the WCD 18 in subsequent communications, and can also
indicate a timing offset for the WCD 18 to use to account for
propagation delays to the eNodeB 26 or to otherwise synchronize
uplink communications.
The WCD 18 uses the uplink resources assigned in the RAR and sends
the eNodeB 26 a connection request. Among other information, the
connection request may include a unique identifier for the WCD 18
(e.g., a temporary mobile subscriber identity (TMSI), a previously
assigned C-RNTI, a random number, or another unique identifier).
The WCD 18 then monitors the downlink resource granted in the RAR
for a response from the eNodeB 26. The eNodeB 26 responds with a
contention resolution message that includes the WCD's unique
identifier. Receiving a matched unique identifier in the contention
resolution message provides confirmation that the WCD's connection
request was received by the eNodeB 26. A failure to match may
occur, for example, if multiple WCDs transmitted the initial
preamble message in the same time-frequency window using the same
preamble code. If the signal from one of the WCDs is stronger than
the other(s), the base station may be able to decode the preamble
message (and subsequent connection request) from that one WCD, but
not the other(s). The WCD that sent the weaker signal may still
receive the RAR, but the unique identifier included in the
connection request message (and subsequent response from the base
station) allows a given WCD to determine whether the eNodeB 26 is
receiving and decoding signals from that WCD or from another
WCD.
The contention resolution message thus resolves the contention due
to the possibility of multiple WCDs using the same preamble code.
If a WCD receives a contention resolution message that does not
match its unique identifier, the WCD discards its temporary C-RNTI
and restarts the random access procedure by selecting a new
preamble code and transmitting another preamble message over PRACH.
The WCD that passed contention resolution (i.e., that received back
its matching unique identifier) promotes its temporary C-RNTI to a
full C-RNTI for use in subsequent communications with the eNodeB
26, and continues exchanging messages with the base station as
necessary to setup a connection.
In some arrangements, when the eNodeB 26 does not have enough
available network resources to accommodate additional traffic, the
eNodeB 26 may respond to a PRACH preamble message, or to a
subsequent service request, by denying the attempt to connect and
then sending an appropriate message to the originating WCD. To
effect a denial, the eNodeB 26 may send a rejection message, a
release message, and/or a redirection message. A rejection message
may be sent in response to a connection request and is used to
notify the WCD 18 that the eNodeB 26 is too congested by network
traffic to allocate resources for the WCD 18. Instead, the
rejection message instructs the WCD 18 to wait for some interval,
in idle mode, until attempting another connection. A release
message may be sent following a service request and, like the
rejection message, causes the WCD 18 to transition to idle mode and
wait for some interval before attempting another connection. A
redirection message identifies another nearby eNodeB or other
resource so as to cause the WCD 18 to scan for the other resource
and initiate a connection, which thereby redirects the WCD 18 to
the other identified resource.
Following a rejection message or release message, the idle WCD 18
generally initiates the random access procedure yet again to make a
connection with the eNodeB 26. But the eNodeB 26 may still be
congested when the next preamble message is received, at which
point the eNodeB 26 may deny the WCD 18 yet again. The process of
unsuccessfully undertaking the random access procedure may
therefore be repeated until the eNodeB 26 has adequate network
resources to allocate resources to the WCD 18, at which point a
connection may be successfully established. In the interim, the
communications between the WCD 18 and the eNodeB 26 consume
resources on PRACH and various control channels. Among other
effects, the elevated communications on PRACH leads to increased
contention in the random access procedure. Embodiments of the
present disclosure provide an enhanced approach to managing PRACH
resources under loaded conditions. In practice, upon receiving a
service request that cannot be accommodated due to network loading,
rather than send a release message, the eNodeB 26 sends a message
to instruct the WCD 18 to idle and wait for a page message before
re-attempting the random access procedure for the purpose of
submitting a service request for the same or greater quantity of
network resources. Such a message is referred to herein as a
wait-for-page communication. The eNodeB 26 saves the service
request and waits for its capacity of available network resources
to increase. Once sufficient network resources are available to
accommodate the saved service request, the eNodeB 26 pages the WCD
18, which causes the WCD 18 to initiate the random access
procedure, transition to connected mode, and submit another service
request to the eNodeB 26.
II. Example Signal Flow
FIG. 2 shows an example signaling process between the WCD 18, the
eNodeB 26, and the MME 34. In particular, FIG. 2 illustrates
signaling that occurs in an LTE system when the wait-for-page
communication is sent in response to a service request. A timeline
101 indicates the timing of certain signals in the signal flow
diagram in FIG. 2. For example purposes, the various communications
represented in FIG. 2 are designated in accordance with messages
used in the radio resource control (RRC) protocol, such as
connection requests, service requests, acknowledgements, and so on.
Moreover, it is noted that alternative implementations may include
more or less specific communications between various entities, such
as overhead communications, acknowledgements, status inquiries and
reports, and so forth. The signaling process illustrated by FIG. 2
may therefore be supplemented and/or modified to comply with
specific signaling protocols, standards, etc., as will be
appreciated.
The signaling process begins with the WCD 18 initiating the random
access procedure. In practice, the WCD 18 detects system
information broadcast from the eNodeB 26, randomly selects a
preamble code, and transmits a preamble message 102 to the eNodeB
26 over PRACH at time T.sub.0. The eNodeB 26 receives the preamble
message 102 and responds with a random access response message
(RAR) 104. The RAR 104 can assign initial uplink and downlink
control channel resources to allow the WCD 18 to exchange further
information with the eNodeB 26.
The WCD 18 uses the uplink resources assigned by the RAR 104 and
sends the eNodeB 26 an RRC Connection Request 106. The WCD 18 then
monitors the downlink resource indicated in the RAR 104 for an RRC
Connection Setup 108 from the eNodeB 26. The WCD 18 receives the
RRC Connection Setup 108 from the eNodeB 26, at time T.sub.1, which
resolves the contention in the random access procedure (e.g., by
matching a unique identifier included in the RRC Connection Request
106). The RRC Connection Setup 108 can also include a scheduling
command for the WCD 18 to communicate additional setup information.
In response to receiving the RRC Connection Setup 108, the WCD 18
transitions to connected mode, and sends an RRC Connection Setup
Complete 110 to the eNodeB 26, which includes a service request
(e.g., by including a buffer status report or the like). The eNodeB
26 receives the RRC Connection Setup Complete 110 at time T.sub.2,
and determines whether to grant the service request. The service
request may specify a quantity of data ready to be transmitted from
the WCD 18, and may also specify a particular quality of service
and/or bearer type for carrying that data. If the eNodeB 26
determines that sufficient network resources are available to
accommodate the service request, the eNodeB 26 can communicate with
the MME 34 and/or other network entities to establish tunnels for
bearer data and allocate resources for communications on the air
interface, as described above.
The eNodeB 26 can determine whether it has sufficient network
resources available to accommodate an incoming service request by,
for example, determining a quantity of resource blocks (RBs)
necessary to accommodate the service request, and comparing the
determined quantity with a quantity of available RBs in upcoming
timeslots. The determination may additionally or alternatively be
made based on, for example, comparing the quantity of available RBs
with a threshold value. As used herein, available RBs refer to RBs
in the eNodeB's designated spectrum that are not already allocated
for use by another WCD. Thus, a given eNodeB's capacity of
available network resources (e.g., quantity of available RBs) is
generally a function of both the total bandwidth of that eNodeB's
air interface and the network loading conditions on the eNodeB. In
addition, the quantity of network resources available at any given
time and/or requested by a given service request may be specified
by a quality of service (QoS) parameter (e.g., a measure of bit
rate, latency, etc.), a quality of service class identifier (QCI),
a number of RBs (a bulk number or a number per unit time), a bearer
type, or another measure. As a result, the determination of whether
to grant a given service request may be made on the basis of
whether a particular number of RBs are available per unit time on
an ongoing basis in addition to, or as an alternative to, whether a
particular bulk number of RBs are available during one or more
upcoming timeslots.
If the eNodeB 26 determines it does not have sufficient available
resources to accommodate the service request (as in FIG. 2), the
eNodeB 26 may send the WCD 18 a "wait-for-page" message 112 at time
T.sub.3. The wait-for-page communication 112 is interpreted by the
WCD 18 as a directive that the WCD 18 should, in addition to
transitioning to idle mode, forgo submitting certain service
requests until the WCD 18 receives a page message from the eNodeB
26. In particular, the wait-for-page communication 112 directs the
WCD 18 to idle and to not send service requests for a quantity of
network resources equal or greater than the quantity sought by the
initial service request (in the RRC Connection Setup Complete 110).
As such, the WCD 18 is directed to not re-attempt the random access
procedure (and thus to refrain from transmitting over PRACH) for
the purpose of submitting such a service request until the WCD 18
is paged by the eNodeB 26. Thus, after receiving the wait-for-page
communication 112, the WCD 18 can be configured to operate in idle
mode and, while idling, to consider any proposed service requests
before initiating the random access procedure for the purpose of
submitting those service requests. In practice, the WCD 18 can
check whether a proposed service requests specifies an equal or
greater quantity of network resources than the quantity sought
initially, and to only proceed with the random access procedure if
the proposed service request is for a lesser quantity. While
idling, the WCD 18 also monitors a predetermined downlink control
channel (e.g., the PDCCH) for page messages from the eNodeB 26 and
other system information.
To facilitate clarity and expediency in the remaining description
herein, reference is made to WCDs that forgo service requests for a
"greater quantity" of network resources than an initial service
request. But this description encompasses forgoing service requests
for an equal or greater quantity of network resources. For
instance, in network resources may be allocated in distinct
quantities or RB groups associated with different bearer types, or
traffic types, and each the various types may be sorted according
to a hierarchy based on the quantity of network resources consumed
by each. As such, WCDs may then forgo service requests that seek a
bearer type of an equal or greater hierarchical level than the
initial service request.
Moreover, in some examples, rather than directing the WCD to forgo
PRACH transmissions only to the extent they are used to initiate a
service request for a greater quantity of RBs than originally
sought, the wait-for-page communication 112 may simply direct the
WCD 18 to forgo all PRACH transmissions. Alternatively, the
wait-for-page communication 112 may itself include an indication of
a maximum quantity of network resources that may be requested by a
service request. In such an example, the wait-for-page
communication 112 may be interpreted as a directive that prohibits
PRACH transmissions to the extent they are used to initiate service
requests for network resources in excess of the maximum
indicated.
The wait-for-page communication 112 may be implemented as a
modified RRC Release message that includes one or more additional
parameters configured to direct the WCD 18 to perform the desired
functions. The wait-for-page communication 112 may also be
implemented as another modified message in accordance with RRC
protocol, as an entirely new RRC message, and/or as a message in
accordance with another standard or protocol.
Meanwhile, as the WCD 18 idles in response to the wait-for-page
communication 112, the eNodeB 26 saves an indication of the service
request included in message 110 and waits for the capacity of
available network resources to increase. After the capacity of
available network resources increases, the eNodeB 26 sends a page
message 114 to the WCD 18 at time T.sub.4. Upon receiving the page
message 110, the WCD 18 sends a second PRACH preamble message 116.
The eNodeB then responds with a RAR 116, and the WCD 18 sends
another RRC Connection Request 120. In response, the eNodeB 26
sends an RRC Connection Setup message 122, at time T.sub.5.
The WCD 18 then transitions to connected mode, and sends an RRC
Connection Setup Complete 124, which is received by the eNodeB 26
at time T.sub.6. As before, the RRC Connection Setup Complete 124
can include a service request. So long as the eNodeB 26 continues
to have sufficient network resources at time T.sub.6 to accommodate
the service request, the eNodeB 26 sends an S11 application message
126 to the MME 34 that includes the service request. In practice,
the eNodeB 26 can undertake a similar determination as to whether
to grant the second service request (in message 122) as described
above in connection with the initial service request (in message
110). But because the second service request is sent in response to
the eNodeB 26 determining that it has sufficient resources to
accommodate the previously received service request (in message
110), the eNodeB 26 is likely to grant the second service request
unless, for example, there is a decrease in available network
resources between times T.sub.4 and T.sub.6 or an increase in the
quantity of network resources sought by the WCD 18.
If the eNodeB 26 determines to grant the second service request (as
in FIG. 2), the eNodeB 26, MME 34, and/or other network entities
can then exchange additional control communications as necessary to
establish communication links for bearer traffic and resources on
the air interface. Such process may include, for example,
authenticating the WCD 18, establishing tunnel endpoint identifiers
(TEIDs) to map packets of data between the WCD 18, the eNodeB 26,
and the SGW 30, configuring security parameters for such
communications, as well as other functions. Once the communication
link is established, the WCD 18 can exchange packets with remote
entities as desired to thereby satisfy the service request.
III. Example Operations
FIGS. 3 and 4 are flow charts illustrating processes performed by
separate network components to achieve efficient use of the access
channel during loaded conditions by buffering incoming service
requests. The process 50 shown in FIG. 3 may be performed by a base
station, such as an eNodeB, according to an example embodiment. The
process 70 shown in FIG. 4 may be implemented by another network
component, such as a WCD, according to an example embodiment. It
should be understood that the processes 50, 70, or portions
thereof, may be implemented by other network components or
combinations of network components, and/or may be implemented for
other purposes, without departing from the scope of the present
disclosure. For clarity, the various functions in the process 50
are described herein solely from the perspective of an eNodeB
receiving a service request from a particular WCD, and the various
functions in the process 70 are described herein solely from the
perspective of a WCD seeking to connect with an LTE RAN via a
particular eNodeB.
At block 52, the eNodeB receives a service request from a WCD. The
service request may be initiated by an unscheduled transmission on
an access channel or otherwise involve such an unscheduled
transmission on the access channel. For example, the service
request may be preceded by the random access procedure, which is
initiated by a preamble message over PRACH. At block 54, the eNodeB
determines whether network channel resources are available to
accommodate the service request. For example, the eNodeB may
determine a quantity of RBs sought by the service request, and
evaluate whether enough RBs are available during an upcoming
interval to allocate to the WCD. As noted above in connection with
FIG. 2, the quantity of network resources sought by the service
request may be specified based on various factors, such as an
amount of data to be carried, a quality of service class identifier
(QCI), a bearer type, a minimum bit rate or latency, or another
indicator related to a total number of RBs and/or a desired number
of RBs per unit time. Accordingly, the eNodeB may make the
determination at block 54 by evaluating the quantity of traffic
channel RBs available in an immediate upcoming interval as well as
on an ongoing basis and comparing that quantity with the quantity
sought by the service request.
If, in block 54, the eNodeB determines that network resources are
available to accommodate the service request, then the process 50
proceeds to block 66. At block 66, the eNodeB allocates network
resources to the WCD and provides a schedule of the allocated
resources to the WCD. The eNodeB may also coordinate with other
network entities to establish links within the RAN for carrying
bearer traffic between the WCD and remote entities (e.g., tunnels
for carrying communications between the WCD and a gateway system).
Block 66 thus includes transitioning the WCD from idle mode to
connected mode. Following block 66, the WCD can engage in
communications with remote entities using the allocated
resources.
If, in block 54, the eNodeB determines instead that resources are
not available to accommodate the service request, then the process
50 proceeds to block 56. At block 56, the eNodeB saves an
indication of the service request in a memory. For example, the
eNodeB may save data indicative of the quantity of network
resources sought by the service request and a unique identifier for
the originating WCD to facilitate sending a page to that WCD
subsequently. As used herein, saving data indicative of a received
service request along with identifying information for the WCD that
sent the service request is generally referred to as "buffering"
the service request.
At block 58, the eNodeB sends a wait-for-page communication to the
WCD. As described above in connection with FIG. 2, the
wait-for-page communication causes the WCD to forgo at least some
transmissions on the access channel until the WCD receives a page
message from the eNodeB. The prohibition on transmissions over the
access channel may extend to access channel transmissions used to
initiate a service request for the same or greater quantity of
network resources than the quantity sought by the initial service
request. Additionally or alternatively, the temporary prohibition
caused by the wait-for-page communication may extend to all service
requests, or to service requests seeking a quantity of network
resources greater than a quantity specified by the wait-for-page
communication. For instance, the eNodeB may include in the
wait-for-page communication an indication of the quantity of its
available network resources, and the WCD can then forgo service
requests seeking a greater quantity.
At block 60, the eNodeB waits for the capacity of its available
network resources to increase. The wait block 60 may involve
iteratively evaluating the capacity of available network resources
(e.g., the quantity of available RBs) and, for each iteration,
determining whether the capacity is sufficient to accommodate the
service request saved in memory. The wait block 60 may additionally
or alternatively involve repetitively evaluating the capacity of
available network resources, and comparing the capacity with a
threshold value. Upon determining that the available capacity is
sufficient to accommodate the saved service request (or exceeds a
threshold), the process 50 may proceed with block 62.
Meanwhile, as the eNodeB waits for its capacity of available
network resources to increase, in block 60, the WCD operates in
idle mode and monitors a predetermined control channel for a page
message. At block 62, the eNodeB may send a page message to the
WCD. The page message overrides the WCD's prohibition on certain
access channel transmissions imposed by the wait-for-page
communication, and thereby causes the WCD to send a second service
request to the eNodeB. The second service request may be in
initiated by an unscheduled transmission on the access channel,
such as a preamble message on PRACH.
At block 64, the eNodeB receives the second service request from
the WCD. In response to the second service request, the process 50
may return to block 54 to again determine whether network resources
are available to accommodate the second service request. And then,
upon determining that sufficient network resources are available,
the process 50 may proceed with block 66 to setup the connection.
At block 66 the eNodeB can allocate resources to the WCD so as to
grant the second service request, establish links for carrying
bearer traffic through the RAN, and provides the schedule of
allocated network resources to the WCD, thereby transitioning the
WCD to connected mode.
In some cases, the eNodeB may maintain a buffer of service requests
from multiple WCDs, and can page each WCD in the order in which the
original service requests were received. As a result the eNodeB can
page the WCDs in order, which may help equalize latency associated
with making initial connections among the WCDs served by the
eNodeB. By contrast, in some systems, the eNodeB may make a
connection with whichever WCD happens to submit a connection
request immediately following an increase in available network
resources. To track the order of reception of multiple service
requests, the memory may store an indication of the reception time
for each received service request, for example. Additionally or
alternatively, each service request saved to memory can be
associated with an index number of another incrementing value that
can be used to determine the time order of each saved service
request.
The WCDs associated with each service request in the buffer can
then be paged in order once resources become available. For
example, the eNodeB may evaluate each buffered service request
individually and determine for each buffered service request
whether available network resources are sufficient to accommodate
the service request and, if not, wait until such resources become
available. Upon determining that sufficient network resources are
available to accommodate the next one of the service requests in
the buffer, the eNodeB can then send a page message addressed to
the WCD corresponding to that service request. Then, the eNodeB can
repeat the process for the next buffered service request (e.g., the
service request received next in time).
Referring now to FIG. 4, at block 72, the WCD initiates connection
with an eNodeB using an unscheduled transmission on an access
channel. For example, the WCD may send a preamble message over
PRACH to initiate the random access procedure described above. As
described in connection with FIG. 2, in response to the unscheduled
transmission, the WCD may receive a connection setup message from
the eNodeB, which resolves contention in the random access
procedure, allocates initial uplink and downlink control channel
resources, and transitions the WCD to connected mode. At block 74,
the WCD sends a service request for a particular quantity of
network resources. As noted in FIG. 2, the service request may be
included in a connection setup complete message (e.g., by including
a buffers status report). The service request may specify the
particular quantity of network resources sought by indicating a
quality of service class identifier (QCI), bearer type, bit rate,
latency, or another measure of a quantity and/or rate of resource
blocks sought for the WCD.
At block 76, the WCD receives a wait-for-page communication from
the eNodeB in response to the servicer request. Upon receiving the
wait-for-page communication, the WCD transitions to idle mode
(e.g., adjusts the value of its state parameter), and monitors
predetermined downlink control channels for a page message from the
base station, at block 78. While waiting for the page message
(block 78), the WCD forgoes further unscheduled transmissions to
the eNodeB over the access channel for the purpose of initiating a
service request for an equal or greater quantity of network
resources than sought by the initial service request. Moreover, the
WCD may forgo access channel transmissions for the purpose of
initiating a service request for a quantity of network resources
greater than a quantity indicated by the wait-for-page
communication, or may simply forgo access channel transmissions
entirely. The reduced access channel transmissions thereby reduce
congestion over PRACH that would otherwise occur due to repeated
attempts to complete the random access procedure.
The WCD interprets the wait-for-page communication as a directive
to cause the WCD to operate as described in connection with block
78 (i.e., to forgo at least some use of the access channel). The
wait-for-page communication may be implemented as an enhanced
communication in accordance with the RRC protocol, such as an RRC
Release or RRC Rejection message with one or more extra parameters.
Upon receipt, the WCD may implement the directive by temporarily
removing the particular cell and/or particular base station from a
listing of available cells the WCD is allowed to connect to. For
example, the WCD may maintain a listing of neighboring cells,
perhaps derived in part from system information broadcasts, and
also maintain access control parameters associated with each cell.
The access control parameters can specify whether or not the WCD is
permitted to initiate connection with those cells (e.g., by
initiating the random access procedure and sending a connection
request). Implementing the directive from the wait-for-page
communication may involve adjusting the access control parameters
(until receipt of a subsequent page) such that the WCD is barred
from sending another connection request to the same cell for the
same connection type, or for a connection type that demands an even
greater quantity of network resources.
In addition to waiting for the page message from the particular
eNodeB, in block 78, the WCD may also attempt to initiate a
connection with another base station. For example, after receiving
the wait-for-page communication, the WCD may monitor pilot signals
from another eNodeB with an overlapping coverage area, and attempt
to register with such other eNodeB. The WCD may send a registration
request and/or access request to the other eNodeB. Of course, in
practice, registering with the other eNodeB generally involves
using the random access procedure to initiate communications with
the other eNodeB. To allow the WCD to proceed as such, the
wait-for-page communication's instruction to forgo further access
channel transmissions can be implemented with eNodeB specificity.
For example, the WCD may forgo sending service requests (preceded
by access channel transmissions) to the particular eNodeB that sent
the wait-for-page communication, but still send access channel
transmissions to other eNodeBs.
In the event the WCD successfully forms a connection with another
eNodeB during block 78, the process 70 may end and the WCD may
ignore a subsequent page message from the particular eNodeB.
Additionally or alternatively, upon the WCD being registered with
the network via another eNodeB, the MME (or another network entity)
may notify the particular eNodeB and that eNodeB can then remove
the pending service request from its memory. Such communications
may occur, for example, in response to the WCD informing the LTE
RAN (after connecting through the other eNodeB) that the WCD
previously received a wait-for-page communication from the
particular eNodeB.
However, in circumstances in which the WCD is unsuccessful in
connecting to another base station, or in which there are no base
stations with overlapping coverage areas, the WCD continues to wait
in idle mode until it receives a page. Then, at block 80, the WCD
receives a page message from the eNodeB. The page message allows
the WCD to again utilize the access channel without restriction. In
other words, the overrides the earlier instruction imposed by the
wait-for-page communication to forgo (at least some) transmissions
using the access channel. In response to receiving the page
message, at block 80, the WCD again initiates connection with the
eNodeB using an unscheduled transmission on the access channel, at
block 82. Block 82 may involve, for example, the WCD sending a
preamble message over PRACH. At block 84, the WCD sends a second
service request for network resources. Similar to the first service
request, the second service request may include a buffer status
report that indicates data ready to be sent by the WCD and may
indicate a quality of service class identifier, a minimum bit-rate,
latency, or the like to specify a desired quantity and/or rate of
RBs sought by the WCD.
The eNodeB can then determine to grant the second service request,
and then exchange signals with the MME and/or other network
entities to establish links for bearer communications and allocate
resources for communicating with the WCD over the eNodeB's air
interface. At block 86, the WCD receives a schedule of the
allocated resources from the eNodeB and engages in communication
over the LTE RAN using those resources.
IV. Example RAN Components
FIG. 5 is a simplified block diagram of an example RAN component
91, according to an example embodiment. In particular, FIG. 5
illustrates functional components that might be found in a RAN
component 91 that is arranged to operate in accordance with the
embodiments described above. As shown, the RAN component 91 may
include a communication interface 90, a processing unit 92, and
data storage 94, all of which may be communicatively linked
together by a system bus, network, or one or more other connection
mechanisms 96. The data storage 94 may include a non-transitory
computer readable medium and includes program logic 98 that, when
executed by the processing unit 92, cause the RAN component 91 to
function in accordance with the present disclosure.
In practice, RAN component 91 may take the form of an eNodeB or a
WCD, or may take the form of another component of an LTE network.
Further, the illustrated components of RAN component 91 (e.g.,
communication interface 90, a processing unit 92, and/or data
storage 94) may be distributed and/or subdivided between one or
more entities in an LTE network and/or in another network. It
should be understood that an example system may also take the form
of another network entity or combinations of other network
entities, without departing from the scope of the present
disclosure.
In RAN component 91, communication interface 90 may comprise one or
more or wired or wireless communication interfaces and/or other
associated equipment for engaging in communications with other
network entities and/or for engaging in RF communications with
mobile stations according to one or more air interface protocols.
Thus, the network interface 90 may include antenna structures
configured to send and receive radio communications to define an
interface (e.g., the LTE air interface 36 described above in
connection with FIG. 1B). The communication interface 90 may
comprise any sort of communication link or mechanism enabling the
RAN component 91 to exchange signaling and bearer data with other
network entities, such as used to create tunnels for passing IP
packets between the PGW 32 and WCD 18. Further, processing unit 92
may comprise one or more processors (e.g., general purpose and/or
special purpose processors), such as microprocessors for
instance.
Data storage 94 may be a non-transitory computer readable medium.
For example, data storage 94 may take the form of one or more
volatile and/or non-volatile storage components, such as magnetic,
optical, or organic storage components, integrated in whole or in
part with processing unit 92. As further shown, data storage 94
contains program logic 98 (e.g., machine language instructions)
executable by processing unit 92 to carry out various functions,
such as the functionality of the example methods and systems
described herein.
For instance, in an example in which the networking node 91 is
implemented as a base station, the communication interface 90 may
include one or more antenna structures configured to wirelessly
communicate with WCDs served by the base station over one or more
scheduled channels and over an unscheduled access channel. The base
station can be configured to allocate available network resources
amongst the WCDs by scheduling network traffic over the scheduled
channels so as to accommodate respective demands of the WCDs
indicated, at least in part, by respective service requests
received from the WCDs. A given WCD that does not have allocated
network resources on the scheduled channels with which to
communicate to the base station can be configured to initiate a
connection with the base station by sending an unscheduled
transmission to the base station over the access channel. Also, the
processing unit 92 may be operatively coupled to the antenna
structures of the base station and the processing unit 92 and the
program logic 98 may form a controller configured to (i) receive,
at the base station, a first service request from a particular WCD,
wherein the first service request specifies a particular quantity
of network resources; (ii) responsive to receiving the first
connection request, make a first determination that a capacity of
available network resources on the scheduled channels is
insufficient to allocate the particular quantity of network
resources to the particular WCD; and (iii) responsive to making the
first determination: (a) send a wait-for-page communication to the
particular WCD, wherein the wait-for-page communication causes the
particular WCD to, prior to being paged, forgo transmitting to the
base station over the access channel for the purpose of initiating
a service request specifying a greater quantity of network
resources than the particular quantity of network resources; (b)
store data indicative of the received service request in a memory;
(c) wait for the capacity of available network resources on the
scheduled channels to increase; (d) after waiting for the capacity
of available network resources on the scheduled channels to
increase, make a second determination that the capacity of
available network resources on the scheduled channels is sufficient
to allocate the particular quantity of network resources to the
particular WCD; and (e) responsive to making the second
determination, send a page to the particular WCD.
Example embodiments have been described above. It should be
understood, however, that variations from these embodiments are
possible, while remaining within the true spirit and scope of the
disclosure.
* * * * *
References