WO2015042822A1

WO2015042822A1 - Method for distributing neighbour discovery resources

Info

Publication number: WO2015042822A1
Application number: PCT/CN2013/084297
Authority: WO
Inventors: 韩锋; 孟艳; 蒋琦; 刘铮
Original assignee: 上海贝尔股份有限公司
Priority date: 2013-09-26
Filing date: 2013-09-26
Publication date: 2015-04-02
Also published as: CN105519194A; CN105519194B

Abstract

The present invention relates to a method for distributing neighbour discovery resources by a base station and sending neighbour discovery signals by a user equipment in a wireless communication system, characterized in that a network supporting neighbour discovery and formed by the base station supports a first type of discovery mechanism based on user equipment non-dedication and a second type of discovery mechanism based on user equipment dedication at the same time. The method can be applied to a resource distribution method of D2D neighbour discovery of a cellular network, which enables the network to flexibly distribute neighbour discovery resources according to network conditions. In addition, the distribution can realize the distinguishing of priorities based on subscription, possibilities of collision, etc., thereby improving user experience. Moreover, the method enables both a connected user equipment and a dormant user equipment to support neighbour discovery.

Description

Method for allocating neighbor discovery resources

Technical field

The present invention relates to the field of wireless communications, and more particularly to a method for allocating neighbor discovery resources.

Background Art Device-to-device (D2D) communication as a 3GPP Release 12 technology is being watched by standardization organizations such as 3GPP SA and RAN, thereby supporting various scenarios such as public security and commercial applications. The necessary and core components of D2D communication are neighbor discovery of surrounding user equipment. At this stage, two types of neighbor discovery are defined in RAN1, as follows:

Type 1: The discovery process allocates resources for discovery signal transmission based on non-user equipment specific, wherein these resources can be used for all user equipments or a group of user equipment;

Type 2: The discovery process allocates resources for discovery signal transmission based on user equipment specificity, where:

a) Type 2A: Resources are dynamically allocated to each dedicated neighbor discovery signal transmission instance;

b) Type 2B: Resources are allocated semi-persistently to each dedicated neighbor discovery signal instance.

From the above definition, the discovery of type 1 is a competition-based solution, and the discovery of type 2 is a non-contention-based solution. In fact, the above two types of discovery processes have their own advantages, but also have their shortcomings. The table below shows some of the results of the above two types of analysis: Table 1: Type 1 Type 2 Advantages and Disadvantages Type 1 Type 2 Advantages Simple, Low Overhead, Low Conflict, Compact Network Application to Hibernate User Control Devices Disadvantages High Conflict Possibilities, High Overhead, Unavailable Energy Consumption, No Network control for user devices that are accurate to sleep

However, detailed implementations for neighbor discovery have not been clearly presented so far. And because of their respective advantages and disadvantages, they have not finally decided which type of discovery will be applied in 3GPP, and these contents are crucial for supporting device-to-device communication under cellular networks. Summary of the invention

In light of the above understanding of the background art and the technical problems that exist, the present invention proposes a detailed resource allocation method for neighbor discovery. In particular, in the present invention, a network for neighbor discovery will support both type 1 (non-user device specific) discovery and type 2 (user device specific) discovery. The base station is capable of semi-statically allocating Type 1 and Type 2 discovery resources based on network conditions such as discovery load conditions, user equipment characteristics, discovery of collision conditions, and the like. The base station should broadcast the type 1 resource to all user equipments by means of its system broadcast information, and the user equipment-specific type 2 resources are transmitted to the specific user equipment according to the user neighbor discovery requirements.

Resources discovered by neighbors assigned to Type 1 and Type 2 can be configured in TDM or FDM or federated TDM/FDM. In type 1 resources, The user equipment can autonomously transmit the discovery signal based on carrier sensing or based on predefined rules, and specific predefined rules based on the user equipment identity and neighbor discovery subframes will be given in subsequent embodiments. In order to reduce transmission collisions, a time hopping scheme based on user equipment identification will be introduced into the discovery period, and some hash function is needed to determine when the user equipment should transmit its discovery signal. In the type 2 resource, the base station can explicitly allocate the discovery resource to each D2D user equipment.

Additionally, the base station can determine which user equipment can use which type of discovery resource. Typically, user equipment-specific and non-competitive type 2 resources can be applied to user equipment in a connected state, such as user equipment with high collision probability, high subscription priority, and the like. User equipment such as a dormant state and a connected state user device having a low collision probability, a low subscription priority, etc., can apply a content type 1 based resource.

Further, for each type of discovery mechanism, user equipments with different priority levels are allowed to transmit their discovery signals with different transmission opportunities in one discovery cycle. For example, a user equipment with a high subscription priority is allowed to transmit its discovery signal multiple times with a high transmission opportunity in one discovery cycle. This will increase the likelihood of discovery of these user devices for other surrounding user devices and increase potential D2D communication opportunities. Conversely, a user equipment with a low subscription priority is allowed to transmit only its discovery signal once in a single discovery cycle. This will result in more discovery flexibility for the network and a good user experience for the user.

More specifically, the first aspect of the present invention provides a method for allocating neighbor discovery resources in a base station in a wireless communication system, characterized in that a network formed by the base station supporting neighbor discovery simultaneously supports user equipment based A non-dedicated first type of discovery mechanism and a second type of discovery mechanism based on user equipment.

In a preferred embodiment of the present invention, the base station semi-statically allocates resources for the first type of neighbor discovery and resources for the second type of neighbor discovery according to network conditions.

In a preferred embodiment of the invention, the network condition comprises at least one of the following: - discover signal load conditions;

- user device characteristics; and

- Found a signal collision condition.

In a preferred embodiment of the invention, the base station broadcasts a first type of resource to all user equipments by means of system broadcast information.

In a preferred embodiment of the present invention, the base station sends a second type of resource to a specific user equipment according to a neighbor discovery requirement of a specific user equipment.

In a preferred embodiment of the present invention, the base station configures resources allocated to the first type and the second type of discovery in a TDM or FDM or a combined TDM/FDM manner.

In a preferred embodiment of the present invention, the base station applies a time hopping scheme determined based on the user equipment identity or based on the neighbor discovery subframe during the discovery period and the discovery week.

In a preferred embodiment of the present invention, the time hopping scheme includes:

- 1 ) = 11, (i 1). ^ - /^ modLNj , where the number of discovery subframes for the first type of neighbor discovery mechanism in one discovery period is indicated, t is the current discovery period, M indicates the number of PRB pairs in each discovery subframe, I indicates the number of transmission opportunities allowed, (π^Ο, η^)) are the index and discovery subframe of the PRB pair used during the ith transmission, respectively. And mi (ί) < M; (0 < ^; mi (-1) = 50, and the UE_ID of the dormant user equipment is (IMSI mod 1024), and the UEJD of the connected user equipment is its C-RNTI; or

- ! ^二^+^ )!^ ! ^" , where Jmod , ί = 0,·'',Ι-1, Υ_ _] =ΌΕ identity≠0 , ,4 = 39827 , Ζ = 65537 and i = K/ ² J> 11 ₅ is the index of the time slot allocated to the neighbor discovery in one radio frame, 预 is a predefined time interval between transmission opportunities and is configured by the network through high-level messages.

In a preferred embodiment of the invention, the wireless communication system comprises an LTE system and an IEEE 802.16m system.

In a preferred embodiment of the invention, mutually orthogonally configured for the first Types of discovered resources and resources for the second type of discovery.

A second aspect of the present invention also provides a method for selecting a resource discovered by a neighbor in a user equipment in a wireless communication system, characterized in that the user equipment autonomously transmits based on carrier sensing or based on predefined rules. Discover the signal.

In a preferred embodiment of the present invention, the predefined rule includes a time hopping scheme in the form of a hash function, where the time hopping scheme includes:

- ^(0 = (111,.(-1).[/ - /Z^modLNj, where the number of discovery subframes for the first type of neighbor discovery mechanism in one discovery period is indicated, t is The current discovery period, M indicates the number of PRB pairs in each discovery subframe, I indicates the number of allowed transmission opportunities, and (1^(0,11)) are the PRB pairs used during the ith transmission, respectively. Index and find the subframe and 01)< ;1^( <^;1^(-1) = 50, and the UE_ID of the sleeping user equipment is (IMSI mod 1024), and the UE_ID of the connected user equipment is its C- RNTI; or

- n _i (t) = (Y _i + i»A) mod [N, J , where Y _{ ^(AY^ odD , i = , 7_j = UE identity≠ 0 , A = 9 21 , D = 65537 and i

Is the index of the time slot allocated to the neighbor discovery in a radio frame, Δ is a predefined time interval between transmission opportunities and is configured by the network through high-level messages.

The present invention proposes a resource allocation method for D2D neighbor discovery of a cellular network, which enables the network to flexibly allocate neighbor discovery resources according to network conditions. In addition, the allocation can achieve prioritization based on subscriptions and collision possibilities, etc., thereby improving the user experience. Furthermore, the read method enables both connected user devices and dormant user devices to support neighbor discovery. DRAWINGS

Other features, objects, and advantages of the present invention will become apparent from the Detailed Description of Description

Figure 1 shows an application scenario of a method in accordance with the present invention;

Figure 2 shows Type 1 and Type 2 in TDM mode in accordance with the present invention. Schematic diagram of resource allocation;

3 is a schematic diagram showing resource allocation of Type 1 and Type 2 in a joint TDM/FDM manner according to the present invention;

Figure 4 is a flow chart showing the differentiation of discovery resources in a base station;

FIG. 5 is a schematic diagram showing resource allocation of type 1 and type 2 of an application time hopping scheme;

Figure 6 is a flow chart showing a method of using a base station in conjunction with a user equipment in accordance with the present invention.

Throughout the drawings, the same or similar reference numerals indicate the same or similar devices (module) or steps. DETAILED DESCRIPTION OF THE INVENTION In the following detailed description of the preferred embodiments, reference will be made to The accompanying drawings illustrate, by way of example, specific embodiments The exemplary embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the invention. Therefore, the following detailed description is not to be considered as limiting

Figure 1 shows an application scenario of the method according to the invention, i.e. there is a need for mutual discovery between UE1 and UE2.

The detailed discovery process design will be described below, and the solution can be applied to the LTE system. Of course, similarly, those skilled in the art will appreciate that the solution should be applicable to other systems, such as the IEEE 802.16m system. The following three ^ ¹ introduces the main idea of the present invention, namely: resource allocation type 1 and type 2 neighbor discovery, discovery transmission opportunities and access to subscription priority.

1, resource allocation for type 1 and type 2 discovery

The base station will allocate type 1 and type 2 discovery resources in the form of TDM, FDM or joint TDM/FDM based on the current network. 2 shows a resource allocation diagram of Type 1 and Type 2 in a TDM manner according to the present invention, and 3 shows a schematic diagram of resource allocation for Type 1 and Type 2 in a combined TDM/FDM manner in accordance with the present invention. In the discovery subframe, the resource of type 1 and the resource of type 2 are orthogonally arranged with each other.

Resource configuration can be semi-static. As an example, if the number of user equipments with neighbor discovery requirements is small, then more Type 2 resources can be configured. Conversely, more Type 1 resources can be configured. The base station will broadcast Type 1 resources to all user equipment in the system broadcast information, for example in SIB1. For Type 2 resources, the base station sends explicit user equipment specific commands to indicate the resources used for discovery.

Additionally, the base station can determine which types of discovery resources are used by which connected user devices based on each user device. Typically, Type 2 resources can be applied to user devices in a connected state, such as user devices with high collision probability, high subscription priority, and the like. For example, a user equipment having a connection state such as a low collision probability, a low subscription priority, and a user equipment in a sleep state can apply a content type 1 based resource. Figure 4 shows a flow chart for distinguishing discovery resources in a base station.

2, found transmission opportunities

As indicated above, high priority user equipment is allowed to transmit discovery signals over time in one discovery cycle, thereby enabling other user equipment to discover the user equipment with high probability. The above priority can be determined by the subscription priority of the user equipment or the decision of the base station itself, such as the likelihood of collision. In particular, for type 1 contention-based discovery user equipment, it is advantageous to determine and design rules based on user equipment identity and neighbor discovery subframes. Here, a time hopping scheme in the form of a hash function will be introduced to reduce the likelihood of collision. An example is given below:

Figure 5 shows a resource allocation diagram for Type 1 and Type 2 of an application time hopping scheme. It is assumed that N1 indicates the number of discovery subframes for the Type 1 neighbor discovery mechanism in one discovery period, t is the current discovery period, and M indicates the number of PRB pairs in each discovery process. I indicates the number of transmission opportunities allowed. (rrii (0,^(0) is the index and the discovery sub-frame of the PRB pair used during the i-th transmission, respectively, and mi O M^W A^ has the following formula to give ni(t), ie:

Rij ( = (m, {t~ \) - UE_ ID) mod [N," ϊ = 0,1,..., 1-1 (1)

Where, at the beginning mi (-l) = 50. Note that the above formula is cyclically shifted by the period N1. And the user equipment autonomously selects 111). Each user equipment can transmit its discovery signal using the selected PRB pair.

For a dormant user equipment, its UEJD is given in (IMSI mod 1024). For a connected user equipment, the UE-ID is its C-RNTI itself. The above formula allows the user equipment transmitting on the same subframe to be transmitted on the same subframe at the next time due to the introduction of m^-l). This greatly increases the likelihood of discovery. As shown in Figure 2, the priority is UE3>UE2>UE1. And compared to the discovery signal of UE1 only once, the discovery signal of UE2 and the discovery signal of UE3 are transmitted twice.

In another implementation example, there is the following formula to determine η _; (ί) , which is similar

The search space design of the PDCCH, namely:

! ^ ^二^ + )!!!. !^" , where,

, ί = 0, · · ·, 1 - 1 , 7_! - UE identity≠ 0 , = 39827 , = 65537 and i = [n _s /2j , is the index of the time slot allocated to the neighbor discovery in one radio frame , Δ is a predefined time interval between transmission opportunities and is configured by the network through high-level messages.

The following figure 5 shows an example of the above formula, the priority is UE3>UE2>UEL and the discovery signal of UE2 and the discovery signal of UE3 three times will be transmitted twice compared to the discovery signal of UE1 only once. Here, Δ = ^{2 is} merely exemplary.

Those skilled in the art will appreciate that the invention is not limited to the above formula. based on

UEJD and other forms of formulas and hash functions that may have used discovery sub-frames are also encompassed within the scope of the present invention.

For type 2 discovery user equipment, the base station can explicitly transmit (π, _; (0, η _; (ή) form of discovery resources to transmit its discovery signal.

3, get the subscription priority

6 is a flow chart showing a method for using a base station in cooperation with a user equipment according to the present invention. The first four steps are all prior art and will not be described here. In the 5th step The middle base station will acquire the predetermined priority, and in the sixth step, distinguish the type 1 and type 2 discovery resources based on the acquired subscription priority.

The base station can obtain a subscription priority to determine the discovery resource allocation. For this purpose, Figure 5 shows a simplified registration and authentication process. After accessing the service, the server determines the subscription priority and should send its acknowledgment message to the corresponding base station. Based on this, the base station can determine whether the type 1 or type 2 resource is allocated to the user equipment accordingly.

The present invention proposes a resource allocation method for D2D discovery of a cellular network, which allows the network to flexibly allocate discovery resources according to network conditions. In addition, the allocation enables prioritization based on subscriptions and collision possibilities, etc., thereby improving the user experience. Furthermore, the read method enables both connected user devices and dormant user devices to support neighbor discovery.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments are to be considered as illustrative and not limiting in any way. In addition, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. A plurality of elements recited in the device claims can also be realized by one element. The first, second, etc. words are used to denote names and do not represent any particular order.

Claims

claims

1. A method for allocating neighbor discovery resources in a base station in a wireless communication system, characterized in that the network formed by the base station to support neighbor discovery also supports a first type of discovery mechanism based on non-dedicated user equipment. and a second type of discovery mechanism based on user equipment specificity.

2. The method according to claim 1, wherein the base station semi-statically allocates resources for the first type of neighbor discovery and resources for the second type of neighbor discovery based on network conditions.

3. The method according to claim 2, wherein the network conditions include at least one of the following:

- Discover signal load conditions;

- User equipment characteristics; and

- Signal collision conditions found.

4. The method according to claim 1, wherein the base station broadcasts the first type of resources to all user equipments by means of system broadcast information.

5. The method according to claim 1, wherein the base station sends the second type of resource to the specific user equipment according to the neighbor discovery requirements of the specific user equipment.

6. The method according to claim 1, wherein the base station operates in TDM or

The resources allocated to the first type and the second type of discovery are configured in an FDM or combined TDM/FDM manner.

7. The method according to claim 1, wherein the base station applies a time hopping scheme determined based on the user equipment identity or based on the neighbor discovery subframe during the discovery period and the discovery period.

8. The solution according to claim 7, wherein the time-hopping solution includes:

- n _; ( = (m,. (/ - 1) · C/^ _ / ) mod [N, J , where indicates the discovery subframe used for the first type neighbor discovery mechanism in a discovery cycle The number of , t is the current discovery period, M indicates the number of PRB pairs in each discovery subframe, Ϊ indicates the number of allowed transmission opportunities, (0), 11)) are used during the i-th transmission, respectively. PRB pair The index and discovery subframe are 111 ) <;11 ) <^;1^(-1) = 50, and the UEJD of the dormant user equipment is (IMSI mod 1024), and the UEJD of the connected user equipment is its C- RNTI; or

― n _i (0 = + A)modLN ₁ ‖ , where,

, ϊ = 0,···, 1-1, Y_ _x =UE identity≠0, = 39827, D = 65537 and i = ln _s /2j, 11 ₅ is the time slot allocated for neighbor discovery in a wireless frame The index of , Δ is the predefined time interval between transmission opportunities and is configured by the network via high-level messages.

9. The method according to claim 1, wherein the wireless communication system includes an LTE system and an IEEE 802.16m system.

10. The method according to claim 1, wherein the resources used for the first type of discovery and the resources used for the second type of discovery are configured orthogonally to each other.

11. A method for selecting resources for neighbor discovery in user equipment in a wireless communication system, characterized in that the user equipment autonomously transmits discovery signals based on carrier sensing or based on predefined rules.

12. The method according to claim 11, wherein the predefined rules include a time-hopping scheme in the form of a hash function, wherein the time-hopping scheme includes:

-

, where, indicates the number of discovery subframes used for the first type of neighbor discovery mechanism in a discovery cycle, t is the current discovery cycle, M indicates the number of PRB pairs in each discovery subframe, and I represents The number of transmission opportunities allowed, (1^(0, 11)) are the index of the PRB pair used during the i-th transmission and the discovery subframe respectively and ]^(0<;1)<^₁;1^( -1) = 50, and the UE ID of the dormant user equipment is (IMSI mod 1024), and the UE_ID of the connected user equipment is its C-RNTI; or

― 11 )=(¾+ , )1110(1[>^》, where =( 1^)11 (^ , ΐ = 0,···,Ι-1 , 7_! = UE identity≠ 0 , = 39827 , D = 65537 and z' = L" _s / ² ", ^ is the index of the time slot allocated to neighbor discovery in a radio frame, Δ is the predefined time interval between transmission opportunities and is determined by the network via higher layer messages Make allocation