CN106604207B

CN106604207B - Packet-based cell access and selection method in M2M communication

Info

Publication number: CN106604207B
Application number: CN201611069710.5A
Authority: CN
Inventors: 徐少毅
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2016-11-22
Filing date: 2016-11-22
Publication date: 2020-03-17
Anticipated expiration: 2036-11-22
Also published as: CN106604207A

Abstract

The invention provides a packet-based cell access and selection method in M2M communication. The method comprises the following steps: grouping the MTCD equipment according to the service characteristics of the MTCD of the machine type communication equipment, and determining a group length MTCD equipment for each group; the MTCD equipment sends an access request signaling to a base station, and the base station broadcasts own state information after receiving the access request signaling, wherein the state information comprises: available subcarriers and the remaining power space of each subcarrier; and the group leader MTCD equipment judges whether to request to access the base station or not according to the state information and the service characteristics of all MTCD equipment in the group. According to the invention, MTCD devices with the same service and close distance are grouped based on the characteristics of the mass of MTCD devices, and the application and selection of cell access are carried out by taking the group as a unit, so that a signaling storm generated when the mass of MTCD devices are independently applied can be avoided, and the blockage of a PUCCH channel is effectively avoided.

Description

Packet-based cell access and selection method in M2M communication

Technical Field

The invention relates to the technical field of wireless communication, in particular to a grouping-based cell access and selection method in M2M communication.

Background

With the rapid development of M2M (Machine to Machine) service, the convergence of M2M and LTE-a (LTE-Advanced) network is a necessary trend for future communication development, and is also an important application scenario in fifth generation mobile communication (5G). But this also presents some new challenges for M2M communication over LTE-a networks. Since M2M devices are numerous and mainly perform uplink communication, uplink resource scheduling is one of the major problems to be solved.

M2M communication has several features:

the number of M2M devices is huge, several orders of magnitude higher than the number of H2H (human-to-human) devices. It is reported that the number of H2H users and the number of M2M devices active in a cell are roughly 50 and 30000, respectively, and 3GPP recommends that a single cell should support at least 1000 MTCD devices.

The data packets sent by M2M devices vary widely. For example, a conventional measurement device may send only a few bits of data, while a video device like a monitor probe will have data volume on the order of Mbps.

The QoS (Quality of Service) requirements are also different. Some devices are time-tolerant, such as smart meters, water meters and other devices which report some readings regularly; but some have strict time constraints such as monitoring and alarm type devices. The requirements of the devices in different application scenarios, such as throughput and packet loss rate, are also different.

The triggering modes of the reported data are different. Some are periodic and some are event triggered.

Low mobility. M2M devices are fixed in position, move infrequently or move at low speed in a defined area.

Since the requirement of M2M communication, generally MTCD (Machine Type communication Device), reports a data volume much larger than that of control signaling sent by a base station or MTCG (Machine Type communication gateway), the scheduling and resource allocation of uplink data are mainly contradictory, and this is exactly contrary to the communication characteristics of cellular networks.

Due to the nature of the above M2M communications, especially considering the massive nature of MTCDs, it is clearly not reasonable if multiple MTCDs access a macrocell simultaneously, since the number of devices that can be accommodated by each macrocell is limited, and so many devices sending access requests to the macrocell base station simultaneously would incur a significant amount of signaling overhead. Meanwhile, the macro base station is overloaded, and the surrounding small base stations may not have enough users, which results in unbalanced load and waste of energy.

Disclosure of Invention

The embodiment of the invention provides a packet-based cell access and selection method in M2M communication, so as to avoid channel blockage generated when massive MTCD (multiple terminal communication device) equipment applies for independently.

In order to achieve the purpose, the invention adopts the following technical scheme.

A method for packet-based cell access and selection in M2M communication, comprising:

grouping the MTCD equipment according to the service characteristics of the MTCD of the machine type communication equipment, and determining a group length MTCD equipment for each group;

the group leader MTCD equipment sends an access request signaling to a base station, and the base station broadcasts own state information after receiving the access request signaling, wherein the state information comprises: available subcarriers and the remaining power space of each subcarrier;

and the group length MTCD equipment judges whether to request to access the base station or not according to the state information and the service characteristics of all MTCD equipment in the group where the MTCD equipment is located.

Further, the grouping the MTCD devices according to the service characteristics of the MTCD devices to determine a group length MTCD device for each group includes:

according to the service characteristics of each MTCD device, the MTCD devices with the same service characteristics are divided into a cluster, the MTCD devices in a specified position range in the cluster are divided into a group, each group is allocated with a group ID, one group length MTCD device is selected from all the MTCD devices in each group according to a set rule, and the reporting period of the MTCD devices in each group is adjusted to be the same time point and period, wherein the service characteristics comprise: at least one of QoS, delay tolerance threshold, data transmission period, residual capacity, minimum time advance, channel state information with the base station, memory and buffer area required when transmitting data.

Further, the selecting a group length MTCD device from all MTCD devices in each group according to a set rule includes:

selecting MTCD equipment with the most residual capacity from all MTCD equipment in each group as MTCD equipment with the group length;

alternatively, the first and second electrodes may be,

selecting an MTCD device with the best channel state with a base station from all MTCD devices in each group as a group length MTCD device;

alternatively, the first and second electrodes may be,

selecting the MTCD equipment with the minimum time advance from all MTCD equipment in each group as the MTCD equipment with the group length;

alternatively, the first and second electrodes may be,

selecting MTCD equipment with the largest memory from all MTCD equipment in each group as group length MTCD equipment;

alternatively, the first and second electrodes may be,

the MTCD device requiring the minimum or maximum buffer level or closest to the full-group average buffer level when transmitting data in the full group is selected from all the MTCD devices in each group as the group length MTCD device.

Further, the method further comprises the following steps:

the number of MTCD devices in each group, K, is determined by:

k ═ n TB × capacity per TB)/resource required by each MTCD device

Wherein nTB is the number of TB allocated to the group;

each MTCD device in the group is assigned a device index number, and the MTCD device ID is the group ID + device index number.

Further, the method further comprises the following steps:

the method comprises the steps of classifying special equipment specially used for monitoring and alarming types into a special access group, wherein the special access group does not set an access group length, the special access group sets a group ID, each MTCD equipment in the special access group has a terminal index number, and the ID of the MTCD equipment is the group ID plus the equipment index number.

Further, the group leader MTCD device sends an access request signaling to the base station, and the base station broadcasts its own state information after receiving the access request signaling, where the state information includes: the available subcarriers and the remaining power space for each subcarrier include:

the MTCD serving as the group length calculates the maximum power strength of a sending signaling according to the power consumption of all MTCD equipment of the group, and sends an access request signaling according to the sending power lower than the maximum power strength;

after receiving the access request signaling, each eNB and other small cell base stations broadcast their own status information on different frequencies, where the status information includes: the available subcarriers and the remaining power space for each subcarrier.

Further, the determining, by the group leader MTCD device, whether to request access to the base station according to the status information and the service characteristics of all MTCD devices in the group in which the MTCD device is located includes:

after receiving state information broadcasted by a base station, a group leader MTCD device extracts available subcarriers and the remaining power space of each subcarrier in the state information, and when the remaining power space of the available subcarriers is larger than the required resource of the group, judges that the group can access the cell of the base station, and sends an access cell request signaling to the base station on an access channel, wherein the access cell request signaling carries the required resource of all MTCD devices in the group, and the required resource of the group is the sum of the required resources of all MTCD devices in the group;

and after receiving the access cell request signaling, when the required resources of all the MTCD equipment in the group carried in the access cell request signaling are smaller than the remaining power space of the available subcarriers and the number of the remaining users capable of being accommodated by the base station is larger than the total number of the MTCD equipment in the group, allowing the group with the long MTCD equipment to access the cell.

Further, the method further comprises the following steps:

the access cell request signaling also carries service priority information of the group, when the base station receives the access cell request signaling sent by a plurality of group length MTCD devices, required resources of all the MTCD devices of the group carried in each access cell request signaling are smaller than the remaining power space of available subcarriers, and the number of the remaining users which can be accommodated by the base station is larger than the total number of the MTCD devices of the group, the service priorities of the groups are compared, and the group with higher service priority is allowed to access the cell.

Further, the method further comprises the following steps:

when the group is not successfully accessed to the cell after a set time period, the group leader MTCD equipment increases the transmission power of an access request signaling, and transmits the access request signaling on an access channel according to the increased transmission power, wherein the increased transmission power is less than the maximum power strength of the transmission signaling of the group; or, the group leader MTCD equipment sends a special distress signal to prompt a nearby base station in a sleep mode to wake up to realize cell access.

Further, the method further comprises the following steps:

after sending a request access signaling on an access channel, the group leader MTCD equipment monitors the access channel, if the request access signaling sent by other group leader MTCD equipment is monitored, the monitored request access signaling is analyzed, and when the analyzed request access signaling is the same as a target cell in the request access signaling sent by the group leader MTCD equipment and the priority of an analyzed group is higher than that of the group where the group leader MTCD equipment is located, the target cell in the request access signaling sent by the group leader MTCD equipment is changed or the request access signaling is sent after the group leader MTCD equipment backs off for a period of time.

As can be seen from the technical solutions provided by the embodiments of the present invention, the embodiments of the present invention group MTCD devices having the same service and a close distance based on the characteristics of mass MTCD devices, and apply and select cell access in units of groups, so that signaling storms generated when mass MTCD devices apply for individually can be avoided, and the blocking of PUCCH channels is effectively avoided.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.

Fig. 1 is a process flow diagram of a method for packet-based cell selection and access according to an embodiment of the present invention;

fig. 2 is a schematic diagram of grouping MTCD devices according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

For the convenience of understanding the embodiments of the present invention, the following description will be further explained by taking several specific embodiments as examples in conjunction with the drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.

Based on the problems in the prior art, the embodiment of the invention provides a cell selection and access method based on grouping, which can effectively avoid the overload of a macro base station and can also realize the cell access problem of massive MTCDs.

The processing flow of the above method for packet-based cell selection and access is shown in fig. 1, and includes the following processing steps:

step 1, grouping the MTCD devices according to the service characteristics of the machine type communication devices MTCD, and determining a group length MTCD device for each group.

Fig. 2 is a schematic diagram of grouping MTCD devices according to an embodiment of the present invention. The grouping process of the MTCD devices includes three processes of clustering, grouping, and group length determination, and first, MTCD devices having the same traffic characteristics are grouped into a cluster according to the traffic characteristics of the respective MTCD devices. Grouping the MTCD equipment in a specified position range in a cluster into a group on the basis of the cluster, and allocating a group ID to each group, wherein the service characteristics comprise: QoS (Quality of Service), delay tolerance threshold, data transmission period, residual capacity, minimum time advance, channel state information between base stations, memory and buffer required for transmitting data.

The number of MTCD devices in each group, K, is determined by:

k ═ n TB × capacity per TB)/resource required by each MTCD device

Wherein nTB is the number of TB allocated to the group;

each MTCD device in the group is assigned a device index number, and the MTCD device ID is the group ID + device index number. To facilitate storage and management of information, the ID numbers of the member MTCD devices in the group are set to be continuously distributed. The capacity of each TB (Transmission Block) is set according to actual conditions.

Then, a long MTCD device is selected from all MTCD devices in each group according to a set rule, and for devices in the normal access group, if data needs to be reported periodically, the reporting periods of the members in the group can be adjusted to the same time point and period. The group length determination may use the following different rules depending on the application. The information can be obtained by the base station after the random access is successful and the channel measurement is performed, and the rule for determining the setting of the group length comprises:

alternatively, the first and second electrodes may be,

The special equipment specially used for monitoring and warning types is classified into a special access group, for the special access group, because members of the group are some equipment with monitoring and warning functions, the QoS and the time and period of initiating a request are difficult to predict (basically no period can be said), and the required time delay is very strict, therefore, a group length is not set for the group, the members in the access group can automatically initiate an uplink scheduling request when needed, and the specific process is the same as that of normal LTE equipment. The special access group sets a group ID, each MTCD device in the special access group has a terminal index number, and the ID of the MTCD device is the group ID plus the device index number.

The MTCD devices are grouped together for the purpose of grouping MTCD devices with the same traffic characteristics, and then a group leader performs a Request for Uplink resources on behalf of the entire group, so that PUCCH (Physical Uplink Control CHannel) CHannel blocking due to SR (Scheduling Request) information being transmitted when a single MTCD device applies for resources is avoided as much as possible.

When a new MTCD device first accesses the network, after the random access is successful, the MTCD device reports its corresponding M2M service characteristics to the base station. And the base station allocates a group ID and an equipment index number to the MTCD according to the service characteristics reported by the MTCD equipment, and when the MTCD number of the group to which the MTCD belongs is greater than the preset maximum value, the base station automatically adds a group ID, namely newly builds a group. Each member knows the group ID of the access group in which it is located, which ID will be used as a mask for use when transmitting common signaling on the PDCCH channel, thereby reducing the signaling load of the PDCCH channel.

And step 2, the group leader MTCD equipment sends an access request signaling to the base station. The base station broadcasts own state information after receiving the access request signaling, wherein the state information comprises: the available subcarriers and the remaining power space for each subcarrier.

After grouping the MTCD equipment according to the same service type, the group leader initiates an access request. From the perspective of saving the MTCD power consumption, the MTCD serving as the group length calculates the maximum power strength of the sending signaling according to the power consumption of all MTCD equipment in the group, and sends the access request signaling according to the sending power lower than the maximum power strength.

After receiving the access request signaling, each eNB and SBS (Small Cell Base Station) broadcasts its own status information on different frequencies, where the status information includes: the available subcarriers and the remaining power space for each subcarrier. Note that to avoid collision of multiple signals, the broadcast information should be frequency divided, i.e. broadcast on different frequencies.

When the eNB and the SBS accommodate new users, the eNB and the SBS change their own state information and broadcast it in a new access period.

And step 3, the group leader MTCD equipment judges whether to request to access the base station or not according to the state information and the service characteristics of all MTCD equipment of the group in which the MTCD equipment is positioned.

And after receiving the state information broadcasted by the base station, the group leader MTCD equipment judges whether the base station can be accessed according to the state information. Extracting the available subcarriers and the remaining power space of each subcarrier in the state information, when the remaining power space of the available subcarriers is larger than the required resources of the group, judging that the group can be accessed to the cell of the base station, and sending an access cell request signaling to the base station on an access channel, wherein the access cell request signaling carries the required resources of all the MTCD devices of the group, and the required resources of the group are the sum of the required resources of all the MTCD devices of the group. And if the MTCD equipment with the group length judges that the base station cannot be accessed according to the state information, continuing to wait and selecting other base stations.

In practical application, the access cell request signaling also carries service priority information of the group, when the base station receives the access cell request signaling sent by a plurality of group length MTCD devices, and the required resources of all MTCD devices of the group carried in each access cell request signaling are smaller than the remaining power space of the available subcarriers, and the number of the remaining users that can be accommodated by the base station is larger than the total number of the MTCD devices of the group, the service priorities of the groups are compared, and the group with higher service priority is allowed to access the cell.

For a group leader MTCD Device with D2D (Device-to-Device direct communication) functionality, a request access signal is sent on an access channel and the channel is listened to at other times. If the request access signaling sent by other group leader MTCD equipment is intercepted, the intercepted request access signaling is analyzed, and when the analyzed result shows that the target cell is the same as the target cell in the request access signaling sent by the analyzed group, and the priority of the analyzed group is higher than the priority of the group in which the analyzed group is located, the target cell in the request access signaling sent by the analyzed group is changed or the request access signaling is sent after the target cell is retreated for a period of time.

In practical applications, if the number of MTCD devices under a certain SBS is small, the existing MTCD devices are transferred to other SBS devices, and the SBS devices are temporarily turned off to save power.

The SBS base station may also perform sleep mode to save power when MTCD devices in a cell are in a longer sleep period.

In summary, the embodiments of the present invention group MTCD devices with the same traffic and close distances based on the characteristics of massive MTCD devices, and apply and select cell access in units of groups, so as to avoid signaling storm generated when massive MTCD devices apply for individually, and effectively avoid the blocking of PUCCH channels.

The embodiment of the invention avoids the burden of the base station, transfers the load of the base station to the surrounding small cells and realizes load balance. It is achieved that the MTCD groups that can be accessed are selected according to priority, the higher the priority the higher the probability of access of the group cells. The capacity limit of the small cell is avoided being exceeded when a plurality of MTCD subgroups access a certain SBS simultaneously.

The embodiment of the invention adopts a method of gradually increasing the power of the transmitted signal to save the energy consumption of the MTCD equipment, and adopts the SBS sleep mode and the SBS shutdown mode to effectively save the energy consumption of the SBS.

Those of ordinary skill in the art will understand that: the figures are merely schematic representations of one embodiment, and the blocks or flow diagrams in the figures are not necessarily required to practice the present invention.

From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for packet-based cell access and selection in M2M communication, comprising:

the group leader MTCD equipment judges whether to request to access the base station or not according to the state information and the service characteristics of all MTCD equipment of the group where the MTCD equipment is located;

the group leader MTCD equipment sends an access request signaling to a base station, and the base station broadcasts state information of the base station after receiving the access request signaling, wherein the state information comprises: the available subcarriers and the remaining power space for each subcarrier include:

2. The method of claim 1, wherein the grouping of the MTCD devices according to their traffic characteristics to determine a group length MTCD device for each group comprises:

3. The method of claim 2, wherein the selecting a group length MTCD device from all MTCD devices in each group according to a set rule comprises:

alternatively, the first and second electrodes may be,

4. The method of claim 3, further comprising:

the number of MTCD devices in each group, K, is determined by:

k ═ n TB × capacity per TB)/resource required by each MTCD device

Wherein nTB is the number of TB allocated to the group;

each MTCD device in the group is assigned a device index number, the ID of the MTCD device is the group ID + the device index number, and the TB is the transmission resource block.

5. The method of claim 1, further comprising:

6. The method of claim 5, wherein the determining, by the group leader MTCD device, whether to request access to the base station according to the status information and the traffic characteristics of all MTCD devices in the group to which the MTCD device belongs comprises:

7. The method of claim 6, further comprising:

8. The method of claim 1, further comprising:

9. The method of claim 7, further comprising: