WO2017025795A1

WO2017025795A1 - Method and apparatus for controlling data packet transmission in a device-to-device communication

Info

Publication number: WO2017025795A1
Application number: PCT/IB2016/001178
Authority: WO
Inventors: Yong Liu; Fang-Chen Cheng; Dong Li; Yun DENG
Original assignee: Alcatel Lucent
Priority date: 2015-08-07
Filing date: 2016-07-19
Publication date: 2017-02-16
Also published as: CN106455088A; CN106455088B

Abstract

Embodiments of the present disclosure relate to a method and apparatus for controlling data packet transmission in a D2D communication. The method comprises: obtaining, by a current user equipment, data packet priority information regarding other user equipments; and controlling data packet transmission of the current user equipment based on the data packet priority information. According to the embodiments of the present disclosure, a support mechanism for a data packet priority may be introduced at an access stratum of the D2D communication, thereby supporting preferential transmission of the data packet across different UEs using the data packet priority, further satisfying the priority needs of the application layer, and facilitating a user to use.

Description

METHOD AND APPARATUS FOR CONTROLLING DATA PACKET TRANSMISSION IN A DEVICE-TO-DEVICE COMMUNICATION

FIELD OF THE INVENTION

[0001] Embodiments of the present disclosure relate to a wireless communication field, and more specifically relate to a method and apparatus for controlling data packet transmission in a device-to-device (D2D) communication.

BACKGROUND OF THE INVENTION

[0002] With rapid population of intelligent terminals and exploded growth of network communication capacity, the demand on evolution towards the fifth generation (5G) wireless communication technologies becomes more apparent and urgent.

[0003] In the evolution towards the 5G wireless communication technologies, D2D communication, as a key candidate technology for 5G, has a potential of enhancing system performance, enhancing user experience, and expanding cellular communication applications, and thus attracts wide attention.

[0004] Among wide applications of D2D communication (e.g., the scenario where a fire fighter uses a walkie-talkie to communicate with each other during executing an official duty), user priority needs to be distinguished sometimes (e.g., the head of the firefighting team has a high priority) so as to better support the application and achieve a more user-satisfactory communication.

[0005] However, in R12 version of the long-term evolution (LTE) of the third generation partnership project (3GPP), only a broadcast communication mode was specified for the D2D communication, without providing support to the priority. Therefore, the priority demands at the application level in the D2D communication cannot be satisfied currently at an access stratum.

SUMMARY OF THE INVENTION

[0006] An objective of the embodiments of the present disclosure is to introduce a support mechanism for a data packet priority at the access stratum of the D2D communication, so as to use the data packet priority to support preferential transmission of a data packet across different user equipments (UEs).

[0007] According to an embodiment of the present disclosure, there is provided a method for controlling data packet transmission in a device-to-device communication, comprising: obtaining, by a current user equipment, data packet priority information regarding other user equipments; and controlling data packet transmission of the current user equipment based on the data packet priority information.

[0008] In one embodiment, the obtaining, by a current user equipment, data packet priority information regarding other user equipments comprises: further obtaining, by the current user equipment, resource amount information for data packet transmission regarding the other user equipments; and wherein the controlling data packet transmission of the current user equipment based on the data packet priority information comprises: controlling the data packet transmission of the current user equipment based on the data packet priority information and the resource amount information.

[0009] In one embodiment, the obtaining, by the current user equipment, data packet priority information and resource amount information for data packet transmission regarding other user equipments comprises: monitoring physical side -link control channels of the other user equipments so as to obtain the data packet priority information and the resource amount information.

[0010] In one embodiment, the controlling data packet transmission of the current user equipment based on the data packet priority information and the resource amount information comprises: determining, based on the data packet priority information and the resource amount information, a network traffic load amount associated with priorities higher than the data packet priority of the current user equipment and identical to the data packet priority of the current user equipment; and determining, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment.

[0011] In one embodiment, the determining, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment comprises: determining, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load.

[0012] In one embodiment, the determining whether to continue the data packet transmission of the current user equipment based on the network traffic load comprises: determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount.

[0013] In one embodiment, the determining, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load comprises: continuing the data packet transmission if the network traffic load amount is less than or equal to a predetermined threshold; and further determining whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold.

[0014] In one embodiment, the further determining whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold, comprises: stopping the data packet transmission if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is higher than or equal to the predetermined threshold; and determining whether to continue the data packet transmission based on random resource assignment processing, if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is lower than the predetermined threshold, wherein the random resource assignment processing comprises: performing random permutation on the current user equipment and other user equipments at the same priority as the current user equipment, so as to be assigned with different random priority values; determining, based on the random priority values, a network traffic load amount associated with the current user equipment and other user equipments having a higher priority than the data packet priority of the current user equipment; continuing the data packet transmission if the network traffic load amount is less than or equal to an available resource amount; and stopping the data packet transmission if the network traffic load amount is larger than the available resource amount.

[0015] In one embodiment, the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises: determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and accessing the channel to start the data packet transmission if the channel is idle.

[0016] In one embodiment, the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises: determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determining, if the channel is idle, whether to start the data packet transmission based on a back-off processing, wherein the back-off processing comprises: determining a back-off period based on a current available resource amount and the data packet priority of the current user equipment; and accessing the channel to start the data packet transmission if the channel continues idle during the back-off period.

[0017] In one embodiment, the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises: determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determining, if the channel is idle, whether to start the data packet transmission based on an access probability, comprising: determining an access probability based on a current available resource amount and the data packet priority of the current user equipment; generating a random number between 0 and 1 ; and accessing the channel to start the data packet transmission if the random number is less than or equal to the access probability.

[0018] According to the embodiments of the present disclosure, there is further provided an apparatus for controlling data packet transmission in a device-to-device communication, comprising: an obtaining unit configured to obtain, by a current user equipment, data packet priority information regarding other user equipments; and a controlling unit configured to control data packet transmission of the current user equipment based on the data packet priority information.

[0019] In one embodiment, the obtaining unit is further configured to obtain, by the current user equipment, resource amount information for data packet transmission regarding the other user equipments; and wherein the controlling unit is further configured to control the data packet transmission of the current user equipment based on the data packet priority information and the resource amount information.

[0020] In one embodiment, the obtaining unit monitors physical side-link control channels of the other user equipments so as to obtain the data packet priority information and the resource amount information.

[0021] In one embodiment, the controlling unit is configured to determine, based on the data packet priority information and the resource amount information, a network traffic load amount associated with priorities higher than the data packet priority of the current user equipment and identical to the data packet priority of the current user equipment; and determine, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment.

[0022] In one embodiment, the controlling unit is configured to: determine, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load.

[0023] In one embodiment, the controlling unit is configured to determine, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount.

[0024] In one embodiment, the controlling unit is configured to: determine to continue the data packet transmission if the network traffic load amount is less than or equal to a predetermined threshold; and further determine whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold.

[0025] In one embodiment, the controlling unit is configured to: determine to stop the data packet transmission if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is higher than or equal to the predetermined threshold; and determine whether to continue the data packet transmission based on random resource assignment processing, if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is lower than the predetermined threshold, wherein the random resource assignment processing comprises: performing random permutation on the current user equipment and other user equipments at the same priority as the current user equipment, so as to be assigned with different random priority values; determining, based on the random priority values, a network traffic load amount associated with the current user equipment and other user equipments having a higher priority than the data packet priority of the current user equipment; continuing the data packet transmission if the network traffic load amount is less than or equal to an available resource amount; and stopping the data packet transmission if the network traffic load amount is larger than the available resource amount.

[0026] In one embodiment, the controlling unit is configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and access the channel to start the data packet transmission if the channel is idle.

[0027] In one embodiment, the controlling unit is configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine, if the channel is idle, whether to start the data packet transmission based on a back-off processing, wherein the back-off processing comprises: determining a back-off period based on a current available resource amount and the data packet priority of the current user equipment; and accessing the channel to start the data packet transmission if the channel continues idle during the back-of period.

[0028] In one embodiment, the controlling unit is configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine, if the channel is idle, whether to start the data packet transmission based on an access probability, comprising: determining an access probability based on a current available resource amount and the data packet priority of the current user equipment; generating a random number between 0 and 1 ; and accessing the channel to start the data packet transmission if the random number is less than or equal to the access probability.

[0029] According to the embodiments of the present disclosure, a support mechanism for a data packet priority may be introduced at an access stratum of the D2D communication, thereby supporting preferential transmission of the data packet across different UEs using the data packet priority, further satisfying the priority needs of the application layer, and facilitating a user to use. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0030] The accompanying drawings illustrated here provide further understanding of the present disclosure and constitute a portion of the present disclosure. Schematic embodiments of the present disclosure and their explanations are used for interpreting the present disclosure, not constituting improper limitation of the present disclosure. In the accompanying drawings:

[0031] Fig. 1 illustrates a flow diagram of a method for controlling data packet transmission in a D2D communication according to the embodiments of the present disclosure;

[0032] Fig. 2 illustrates a flow diagram of a method for controlling ongoing data packet transmission in a D2D communication according to the embodiments of the present disclosure;

[0033] Fig. 3 illustrates a flow diagram of a method for controlling arriving data packet transmission in a D2D communication according to the embodiments of the present disclosure; and

[0034] Fig. 4 illustrates a schematic block diagram of an apparatus for controlling data packet transmission in a D2D communication according to the embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] A basic idea of the embodiments of the present disclosure is to introduce a support mechanism for a data packet priority at an access stratum of a D2D communication, so as to use the data packet priority to support preferential transmission of the data packet across different UEs. More specifically, by controlling, based on priorities of data packets transmitted by all UEs on a D2D network, their respective ongoing or arriving data packet transmission at each D2D UE, priority transmission of data packets is implemented on the whole D2D network, i.e., performing transmission according to priority.

[0036] In order to make the objectives, technical solutions and advantages of the present disclosure much clearer, the present disclosure will be illustrated in further detail in conjunction with the accompanying drawings and preferred embodiments.

[0037] In order to facilitate understanding, a typical scenario in a D2D communication network will be first described. In one typical scenario, multiple D2D UEs each transmits data in a broadcast mode designated in the 3GPP LTE R12. Specifically, spectrum resources pre-assigned to a network node such as a base station are partitioned, on a time domain within a scheduling Assignment (SA) period, into an SA control period portion and a data period portion, wherein scheduling information for data transmission is transmitted using its corresponding physical side-link control channel (PSCCH) in the SA control period portion, including resource assignment information, data packet transmission mode, etc.; meanwhile, data/data packets are transmitted using its corresponding physical side -link data channel (PSSCH) in the data period portion. Before D2D broadcast data transmission, the SA control information is first transmitted so as to implement discontinuous reception (DRX). Then, the UE will first decode the SA control information and then decide whether to decode the data packet and how to perform decoding based on the SA control information.

[0038] Fig. 1 illustrates a flow diagram of a method 100 for controlling data transmission in a D2D communication according to the embodiments of the present disclosure. The method may be implemented at each of a plurality of UEs in a D2D communication.

[0039] As illustrated in Fig. 1, at step S 101, a current UE obtains data packet priority information regarding other UEs.

[0040] As well known, an upper layer of the UE may provide a series of data packet priorities of possible values to the access stratum. N priority levels may be represented by integers such as 1, 2, ... , N, wherein a larger value represents a higher priority level.

[0041] As an explicit indication of a data packet priority level, the data packet priority level may be included in the PSCCH as a portion of SA control information, such that the UE may notify the priority level of its data packet to other entity.

[0042] As an implicit indication of a data packet priority level, the data packet priority level is associated with an SA resource pool, such that the SA resource pool is divided based on the data packet priority, such that through the location of the SA control information in the SA resource pool, i.e., the source of the PSCCH, the priority information of data packets to be transmitted in the data period portion of the same SA period may be known.

[0043] According to one embodiment of the present disclosure, the current UE may obtain the data packet priority information regarding other UEs by monitoring the PSCCHs from the other UEs.

[0044] In one specific embodiment, the current UE may obtain, by monitoring the PSCCHs from the other UEs, the SA control information transmitted thereby, then obtaining the data packet priority information regarding the other UEs from the SA control information. For example, the data packet priority information regarding a respective UE is obtained by decoding the SA control information.

[0045] In another specific embodiment, the current UE may obtain which SA resource pool the PSCCH comes from by monitoring the PSCCHs from the other UEs, and then may obtain the data packet priority information regarding a respective UE based on a preconfigured correspondence relationship between the S A resource pool and the data packet priority.

[0046] The current UE, after obtaining the data packet priority information regarding the other UEs, enters into step S 102 to control the data packet transmission of the current UE based on the obtained data packet priority information regarding the other UEs.

[0047] Here, any control scheme known or future developed in the art may be adopted to control the data packet transmission of the current UE based on the obtained data packet priority information regarding the other UEs, so as to implement transmission on the access stratum according to the data packet priority level.

[0048] According to one embodiment of the present disclosure, the data packet transmission of the current UE may be controlled based on the data packet priority information regarding the other UEs by considering the network traffic load amount regarding the data packet priority. Hereinafter, it will be described in more detail so as to better convey the main idea of the present disclosure, without constituting any limitation to the present disclosure.

[0049] For example, according to one embodiment of the present disclosure, in step S 101, the current UE may also obtain the resource amount information for data packet transmission regarding the other UEs. In one embodiment, the resource amount information for data packet transmission regarding the other UEs may be obtained by monitoring the PSCCHs from the other UEs, e.g., the SA control information (e.g., resource assignment information) transmitted therein. The resource amount information for data packet transmission may refer to a spectrum resource for data packet transmission as pre-assigned by a network node such as a base station. For example, the resource amount information for data packet transmission regarding a respective UE is obtained by decoding the S A control information.

According to one embodiment of the present disclosure, the data packet transmission of the current UE may be controlled based on the data packet priority information and the resource amount information for the data packet transmission regarding the other UEs. For example, in one specific embodiment, a network traffic load amount associated with priorities higher than the data packet priority of the current UE and identical to the data packet priority of the current UE is determined based on the data packet priority information and the resource amount information, and whether to perform data packet transmission for the current UE is determined based on the network traffic load amount. In other words, according to the embodiments of the present disclosure, whether to perform data packet transmission of the current UE may be determined without considering a network traffic load amount caused by other UEs that has a lower priority than the data packet priority of the current UE while only considering the network traffic load amount caused by other UEs that have a higher priority than the data packet priority level of the current UE and that have the same data packet priority of the current UE.

[0050] According to one embodiment of the present disclosure, for ongoing data packet transmission of the current UE, it may be determined whether to continue data packet transmission based on the network traffic load amount. According to one embodiment of the present disclosure, for arriving data packet transmission of the current UE, it may be determined whether to start data packet transmission based on the network traffic load amount.

[0051] In the above circumstance, according to one embodiment of the present disclosure, only the network traffic load amount on a current period (S A period) may be considered, or the network traffic load amount on the previous one or more periods may be considered in combination. In one embodiment, whether to perform the data packet transmission of the current UE may be determined based on an average network traffic load amount on a plurality of periods. The present disclosure has no limitation thereto.

[0052] Hereinafter, more detailed depiction of the method above will be made in conjunction with Fig. 2 and Fig. 3.

[0053] Fig. 2 illustrates a flow diagram of a method 200 for controlling ongoing data packet transmission in a D2D communication according to the embodiments of the present disclosure.

[0054] As illustrated in Fig. 2, in step S201, the current UE obtains data packet priority information and resource amount information for data packet transmission regarding the other UEs.

[0055] For example, at the current t"¹ SA period (t is a positive integer), the current UE i obtains data packet priority information PR (j) and resource amount information nRB (j, t) for data packet transmission regarding other UE j. Operation of this step is similar to the operation depicted previously in conjunction with step S101, which will not be detailed here.

[0056] Then, at step S202, based on the data packet priority information and the resource amount information for data packet transmission regarding the other UEs obtained at step S201, a network traffic load amount associated with priorities higher than the data packet priority of the current UE and the priorities identical to the data packet priority of the current UE is determined.

[0057] The network traffic load amount may be a function of the D2D traffic amount and associated priority level. According to one embodiment of the present disclosure, the network traffic load amount may be determined by a weighted sum of the resource block amounts consumed by data packet transmission of relevant UEs. For example, at the UE i, the network traffic load amount WL (t) at the I^th period may be expressed as the following equation (1):

WL (t) = ∑ _{PR U)≥PR {i)]} a(PR ( j), n_SB ( j, t)) n_SB ( j, t)

[0058] j s_B (i.t _{( 1 )}

[0059] Wherein, ^tx ' represents a set of transmitting UEs observed by the UE i at the I^th period; ^ ^ also includes UE i itself if UE i transmits at the t"¹ period. ^^ ⁾ represents the priority level of packets transmitted from UE j. ⁿRB ^J ^^ represents the number of resources/ resource blocks consumed by data packets from UE j at the I^th period. {PR(j)≥PR⁽0} j_{s an} indication function, which indicates that the function value is 1 if PR(j) >PR(i) stands; while the function value is 0 if PR(j) >PR(i) does not stand. is a scaling factor depending on packet priority and the amount of resources consumed by UE j.

[0060] In the example above, two special cases may exist:

[0061] Special case 1 : & (PR ⁽ Λ ^URB ⁽ 0⁾ — 1 _{Then the network traffic load} amount represents the amount of resources consumed by ongoing data packet transmission of UEs having a priority level higher than and identical with the data packet priority level of the current UE.

[0062] Special case 2: ^a (^PR ( Λ RB ⁽ 0⁾ = ^ ^_RB ( j, t) ^ ^ network traffic load amount represents the amount of ongoing data packet transmission of UEs having a priority level higher than and identical with the data packet priority level of the current UE.

[0063] According to one embodiment of the present disclosure, the network traffic load amount may be calculated through moving average of on M (M is a positive integer) SA periods. For example, the network traffic load amount WL may be represented as equation (2) below:

1 ⁰

WL = ∑WL (t)

[0064] ^M (2)

[0065] Next, in step S203, the network traffic load amount WL is compared with the predetermined threshold WL^.

[0066] According to one embodiment of the present disclosure, a predetermined threshold WL_ffe- may be configured by an eNB or pre -configured by a network.

[0067] As well known, in the 3GPP LTE R12 version, a data resource pool (PSSCH) is assigned to the D2D broadcast. With different transmitting patterns employed by transmitting UEs, the data resource pool may accommodate parallel transmissions from multiply transmitting UEs.

[0068] In this case, for example, for N priority levels 1, 2, N, wherein a larger value represen tts a hi-gher priori '_tty, M N t th_iresh_io \lAds WL_t ^m _hr ^r (l), WL_t ^m _hr ^r (2), ... , WL_t ^m _hr ^r (N) may , be con _ffi.gured , for the data resource pool. Because a higher priority needs a smaller traffic load in the data

. WL_thr (l)≥WL_thr (2)≥. . .≥WL_thr (N)

resource pool, ^{mr mr mr}

[0069] In one embodiment, ^ ⁼ (²) ⁼ · · · ⁼

it is only needed to configure a single value for the predetermined threshold. [0070] In another embodiment, ^^™™ may be used to represent the highest priority level of the transmitting UE m ^S* ® , wherem ¾(0 = ¾(/,-^ +l)u...uS_ft(/,-l)uS_ft(/,0) _f ^

[0071] If it is determined ^— ^¾^ir _{m ste}p §203, the method enters into step S209, where the current UE i continues transmitting its ongoing data packet. [0072] If it is determined ^> _{m ste}p §203, the method enters into step S204. In this case, it may be further determined whether the data resource may accommodate a portion of the ongoing data packet transmission with the priority PR (i), so as to sufficiently utilize the network resource. More detailed depiction will be provided hereinafter.

[0073] As illustrated in Fig. 2, in step S204, a network traffic load amount ^^ (ΡΡ(ί)) associated with a priority higher than the data packet priority of the current UE may be determined.

Based on the network traffic load amount _; it _may be further determined whether to continue data packet transmission.

[0074] Here, the network traffic load amount ^^ (ΡΡ(ί)) _may ^_e determined in a similar

WL (PR(i) t) manner as depicted in step S202. For example, the network traffic load amount ^h ' associated with the priority level higher than PR (i) at the I^th period may be represented as following equation (3):

WL_h (PR ( , t) = ∑ l,™o»™( l ⁽-^PR ( Λ U, t )n_RB {j )

[0075] ^JeS'^< -'^} (3)

[0076] In one embodiment, the network traffic load amount ^^ (ΡΚ(ί)) -_{g ca}i_cui_alecj through moving average on M (M is a positive integer) SA periods. For example, the network traffic load amount ^^ (ΡΚ(ί)) _may ¾_{e eX}p_resse(j into equation (4) below:

WL _h (PR (i)) = - - ∑WL _h (PR (i), t)

[0077] ^M '=-« +1 (4)

[0078] In step S205, the network traffic load amount ^^ (ΡΡ(ί)) -_{g com}p_are(j _wi_m the predetermine

[0079] If

method enters into step S210, stopping data packet transmission. In one embodiment, the current UE may stop transmission of relevant data information in the current SA period, or may begin to stop transmission of both relevant SA control information and data information from a next S A period.

[0080] If ^WLh (^PR(¹ ^ < ^WL'hr _{> t}he method proceeds to step S206. This case indicates that the data resource may accommodate a portion of ongoing data packet transmission of the priority PR(i), i.e., only a part of UEs with the priority PR(i) can continue data packet transmission, or only a part of UEs with the priority PR (i) need to stop data packet transmission.

[0081] According to one embodiment of the present disclosure, a random resource assignment method may be employed to further determine whether the current UE continues the data packet transmission. Hereinafter, it will be described with reference to steps S206 - S210.

[0082] In step S206, the current UE and other UEs at a same priority with the current UE are randomly permutated so as to be assigned with different random priority values.

[0083] For example, S(PR(^l ) _may ^_{e use(}j _to represent a set of transmitting UEs at the same priority level with the UE i; this set also includes the UE i, here ^( (i)) ^e ^^a ) _

[0084] According to one embodiment of the present disclosure, random permutation may be performed to the elements in S(PR(iJ) _{^ SQ as tQ 0}¾_{lam m}e set ^^or . Suppose the index of UE j within ^or is ind(j), ind() representing an index mapping function.

[0085] In this way, all transmitting UEs with the same priority as the UE i are randomly ordered, thereby being assigned with different random priority values/ random values.

[0086] Then, in step S207, the network traffic load amount WL_C; associated with the current UE and other UEs having a higher data packet priority than the current UE is determined based on the random priority values.

[0087] In one embodiment of the present disclosure, the network traffic load amount WL_C; of the UEs with an index smaller than or equal to Ind(i) within ^or may be determined. For example, in a similar manner as depicted above, the network traffic load amount WL_C; may be represented as equation (5) below:

1 ⁰

^WL rf = T ∑ ∑i_u,,}a⁽^ ⁽ ½ ⁽ j. ) ¾ ( j.

[0088] t=-M +l je S { PR {i ), lnd { j )< lnd {i ) [0089] Wherein, if UE j performs transmission at the I^th period, ^^{ί ί1} is 1 ; if the UE j does not perform transmission at the I^th period, ^^{ί ί1} is 0.

[0090] Next, in step S208, the calculated network traffic load amount WL_c/ is compared with

WL

current network available resource amount ^av . [0091] In the embodiment of the present disclosure, it may be assumed that WL_av = WL_thr - WL_h (PR(i))

[0092] If it is determined ^{WLd ≤ WL}°^V at step S208, the method proceeds to step S209, where the current UE i continues the data packet transmission. [0093] If it is determined ^{> WL}°^V at step S208, the method proceeds to step S210, where the current UE i stops the data packet transmission.

[0094] What has been described above is a procedure of further determining whether to continue data packet transmission using a random resource assignment method. However, it should be understood that any appropriate method known or future developed in the art may be employed to further determine whether the current UE continues to perform data packet transmission, without limiting to the random resource assignment method.

[0095] For example, in a special case, with reference to step S204, if a ( vPR ( wj)^/,> n K_RB„( v Jj ,' t)) = l / n K_RB„( ^\ Jj ,^■> t) _m . equati .on 3. and _J the transmitting _T U_TCE performs transmission at each period, the UE i may directly determine whether to continue data packet transmission based on the probability, without a need of adopting the random resource assignment method above. For example, the probability of stopping data packet transmission may be represented as equation (6) below:

_ WL _thr - WL _h (P_{R (l ) w}

WL - WL _h (PR (i))

[0096] I l, WL _h (PR (i)) > WL _{lhr (6)}

[0097] In this case, according to one embodiment, the current UE i may generate a random number, and the compares the random number with the probability above, thereby determining whether to continue data packet transmission. For example, if the random number is less than or equal to the probability value above, data packet transmission is stopped; while if the random number is larger than the probability value, data packet transmission is continued.

[0098] What has been depicted above in conjunction with Fig. 2 is a procedure of controlling ongoing data packet transmissions in a D2D communication according to one embodiment of the present disclosure. Hereinafter, a procedure of controlling arriving data packet transmission in a D2D communication according to one embodiment of the present disclosure will be described with reference to Fig. 3. It may be understood that the two control procedures may be separately executed or concurrently executed at the D2D UE.

[0099] Before entering into the data packet transmission state, the UE decodes the SA control information from the transmitting UEs to sense data channels. Controlling the arriving data packet transmission may mean controlling access to the data channels. According to the embodiments of the present disclosure, a busy degree of the channel may be determined by considering network traffic load amount of ongoing transmission associated with the priority identical to or higher than that of the current UE and the traffic load to be transmitted by the current UE, thereby determining an access policy dependent on the busy degree of the channel.

[0100] As illustrated in Fig. 3, in step S301 , the current UE obtains data packet priority information and resource amount information for data packet transmission regarding other UEs. Then, in step S302, network traffic load amount associated with the priorities higher than the data packet priority of the current UE and identical to the data packet priority of the current UE is determined based on the data packet priority information and the resource amount information for data packet transmission regarding other UEs as obtained in step S301. Processing in step S301 and step S302 is similar to the processing in step S201 and step S202 above, which will not be detailed here.

[0101] After the network traffic load amount WL associated with the priorities higher than the data packet priority of the current UE and identical to the data packet priority of the current UE is determined, a busy degree of the channel is determined based on the network traffic load amount WL and the resource amount to be used for data packet transmission of the current UE, thereby determining an access policy based on the busy degree of the channel. Hereinafter, more detailed depiction is provided in conjunction with steps S303- S306.

[0102] In step S303, it is determined whether a sum of the WL and the resource amount for the current UE is greater than a predetermined threshold WL,_¾r.

[0103] In one embodiment, the current UE i may estimate/predict the resource amount to be used for the current UE. for example, the resource amount for the current UE may be predicted _t through frac(i)a(PR(i) ,' η„Λί) )η„Λί) , wherei■n n ^R _K ^B _R ( ·i) ' represent .s an average amount . o _ff the resource blocks to be consumed by the data packet in the SA period; ^J f ic( ^vi ') denotes an average proportion of the SA periods during which the UE i will transmit data packets, for example, if the UE i will transmit data packets in two periods every three periods on average, then frac(l)— 2/3 n_m (i) _an(j frac(l) ^_g derived from the estimation/ prediction by the UE i.

[0104] In step S303, if ^{WL +} frac(i)a(PR(i) , n_RB (i) )n_RB (i) > WL_{thr then ¾ ig} considered that the channel is busy during the current SA period. Therefore, return to step S301 to continue repeating S301 - S303 during subsequent periods.

r_n, _{n;i Tf} WL + frac{i) {PR{i) , n_m {i) )n

M ^β _m ^ΒU) ≤ WL_†hr . . . . . _{t t t} [0105] If , it is considered that the channel is idle in the current S A period. In this case, it may be considered to access the channel.

[0106] In the present embodiment, if the channel is sensed to be idle, the UE may not immediately perform transmission in subsequent SA periods; instead, it may perform back-off processing so as to avoid the circumstance in which multiple UEs start transmission during one SA period. The back-off processing refers to continuously sensing the channel within a specific period after the channel is sensed idle, and accessing the channel if the channel continues idle within the specific period of time. Hereinafter, detailed depiction will be made with reference to steps S304 - S306.

[0107] In step S304, a back-off period is determined based on the current available resource amount and the data packet priority of the current UE.

[0108] According to one embodiment of the present disclosure, the back-off period may be computed based on the number of SA periods. The number m_¾ac¾0j^of SA periods for back-off may be associated with the data packet priority and the current available resource amount, as illustrated in equation (7) below:

[0109] ^m^off = f^PR ⁽ Λ VL, VL_thc ) _(?)

[0110] Wherein, the lower the priority level is, the more is the number of SA periods for back-off. The smaller the current available resource amount is, the more is the number of SA periods for back-off.

[0111] In one embodiment, for example, the back-off period may be further designed into equation (8) below:

[0112] ^Β backoff - =

( i )) )

6(WL - WL)

[0113] wherein " ^thr denotes a scaling factor associated with the current available resource amount, which may be configured by the eNB or pre-configured by the network; ^mfix ^ ¹ ^ denotes a fixed back-off period for the priority PR (i); ^mrd ^ ¹ ^ denotes a random back-off period within [0, CW(PR (i))], wherein CW(PR (i)) denotes a back-off window of the priority PR (i). ^mrd ^ ¹ ^ may be used for preventing multiple UEs with the same priority from simultaneously starting transmission within one SA period. The value m_¾ac¾0j^ of the back-off period is approximated to an integer.

[0114] Next, in step S305, it is determined whether the channel continues idle during the back-off period. The processing in this step may be implemented through a similar processing in step S303, which will not be detailed here.

[0115] If it is determined in step S305 that the channel continues idle, the method enters into step S306 to access the channel to start data packet transmission.

[0116] If it is determined at step S305 that the channel does not continue idle, the method returns to step S301 to continue repeating S301-S305 during a subsequent period, till the channel continues idle during the back-off period and then accesses to the channel.

[0117] In the embodiment depicted in conjunction with Fig. 3, a back-off processing is introduced in the access mechanism; therefore, while providing the priority support, the circumstance in which multiple UEs start transmission simultaneously during one SA period is avoided, thereby reducing the possibility of network congestion and enhancing the D2D communication performance.

[0118] However, instead of back-off processing, in another embodiment, whether to start data packet transmission may be determined based on an access probability.

[0119] According to the embodiments of the present disclosure, the access probability of the UE may be associated with the data packet priority and the current available resource amount. For example, the access probability P_ac of the UE may be represented into equation (9) below:

[0120] P_ac = f(PR \ WL, WL_{t (9)}

[0121] The higher the priority level is, the higher the access probability P_ac is. The larger the

WL - WL

current available resource amount ^thr is, the higher the access probability P_ac is.

[0122] In one embodiment, whether to start data packet transmission may be determined by generating a random number between 0 and 1 and then comparing the random number and the access probability. For example, if the random number is less than or equal to the access probability, the channel is accessed; if the random number is larger than the access probability, the channel is not accessed, and the channel is continued to be sensed.

[0123] The access probability -based access mechanism may also provide priority support, and meanwhile reduce the possibility for multiple UEs to start transmission on one S A period, thereby enhancing the D2D communication performance.

[0124] In other embodiments, the back-off processing might not be performed. Instead, as mentioned above, after sensing the channel idle in step S303, immediately access the channel. However, this access mechanism requires reserving enough margin to an SA resource pool size, such that the SA resource pool can accommodate more transmitting UEs than the data resource pool, and so the reception performance of the SAs at the transmitting UEs is acceptable. In contrast, the back-off processing-based access mechanism and the access probability-based access mechanism as mentioned above do not have such a requirement on the SA resource pool size.

[0125] By far, what has been described above with reference to Figs. 1-3 is a method for controlling data packet transmission based on a data packet priority in a D2D communication according to the embodiments of the present disclosure. Through the method, a support mechanism for the data packet priority may be introduced at the access stratum of the D2D communication, such that the data packet priority is used to support preferential transmission of the data packet across different UEs, thereby enhancing the D2D communication performance.

[0126] Corresponding to the method for controlling data packet transmission in a D2D communication as described above, the embodiments of the present disclosure further provide an apparatus for controlling data packet transmission in a D2D communication.

[0127] Fig. 4 illustrates a schematic block diagram of an apparatus 400 for controlling data packet transmission in a D2D communication according to the embodiments of the present disclosure. The apparatus may be implemented at each of multiple UEs in the D2D communication.

[0128] As illustrated in Fig. 4, the apparatus 400 may comprise an obtaining unit 401 and a controlling unit 402.

[0129] According to the embodiments of the present disclosure, the obtaining unit 401 may be configured to obtain, by a current user equipment, data packet priority information regarding other user equipments. The controlling unit 402 may be configured to control data packet transmission of the current user equipment based on the data packet priority information.

[0130] In one embodiment, the obtaining unit 401 may be further configured to obtain, by the current user equipment, resource amount information for data packet transmission regarding the other user equipments. The controlling unit 402 may be further configured to control data packet transmission of the current user equipment based on the data packet priority information and the resource amount information.

[0131] In one embodiment, the obtaining unit 401 may be configured to monitor physical side -link control channels of the other user equipments so as to obtain the data packet priority information and the resource amount information.

[0132] In one embodiment, the controlling unit 402 may be configured to determine, based on the data packet priority information and the resource amount information, a network traffic load amount associated with priorities higher than the data packet priority of the current user equipment and identical to the data packet priority of the current user equipment; and determine, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment.

[0133] In one embodiment, the controlling unit 402 may be configured to determine, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load.

[0134] In one embodiment, the controlling unit 402 may be configured to determine, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount.

[0135] In one embodiment, the controlling unit 402 may be configured to: determine to continue the data packet transmission if the network traffic load amount is less than or equal to a predetermined threshold; and further determine whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold.

[0136] In one embodiment, the controlling unit 402 may be configured to: determine to stop the data packet transmission if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is higher than or equal to the predetermined threshold; and determine whether to continue the data packet transmission based on random resource assignment processing, if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is lower than the predetermined threshold.

[0137] In one specific embodiment, the random resource assignment processing may comprise: performing random permutation on the current user equipment and other user equipments at the same priority as the current user equipment, so as to be assigned with different random priority values; determining, based on the random priority values, a network traffic load amount associated with the current user equipment and other user equipments having a higher priority than the data packet priority of the current user equipment; continuing the data packet transmission if the network traffic load amount is less than or equal to an available resource amount; and stopping the data packet transmission if the network traffic load amount is larger than the available resource amount.

[0138] In one embodiment, the controlling unit 402 may be configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and access the channel to start the data packet transmission if the channel is idle.

[0139] In one embodiment, the controlling unit 402 may be configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine whether to start the data packet transmission based on a back-off processing if the channel is idle.

[0140] In one specific embodiment, the back-off processing may comprise: determining a back-off period based on a current available resource amount and the data packet priority of the current user equipment; and accessing the channel to start the data packet transmission if the channel continues idle during the back-off period.

[0141] In one embodiment, the controlling unit 402 may be configured to: determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine whether to start the data packet transmission based on an access probability if the channel is idle.

[0142] In one specific embodiment, an access probability is determined based on a current available resource amount and the data packet priority of the current user equipment; a random number between 0 and 1 is generated; and if the random number is less than or equal to the access probability, the channel is accessed to start the data packet transmission.

[0143] The apparatus for controlling data packet transmission in a D2D communication as described above corresponds to the processing of the method for controlling data packet transmission in the D2D communication as previously described. Therefore, its specific details may refer to the method or controlling data packet transmission in the D2D communication as previously described, which will not be detailed here.

[0144] Those skilled in the art should understand that the embodiments of the present disclosure may be provided as a method, an apparatus or a computer program product. Therefore, the embodiments of the present disclosure may adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present disclosure may employ a form of a computer program product implemented on one or more computer usable storage mediums (including, but not limited to, a disk memory, a CD-ROM, an optical memory, etc.) containing computer-usable program codes.

[0145] In a typical configuration, the computing device comprises one or more processors (CPU), an input/output interface, a network interface, and a memory, the memory may comprise a volatile memory, a random access memory (RAM), and/or a non-volatile memory in a computer readable medium, e.g., a read-only memory (ROM) or a flash memory (flash RAM). An internal memory is an example of the computer readable medium.

[0146] The computer readable medium includes a permanent and non-permanent, mobile and immobile medium, which may implement information storage by any method or technology. The information may be a computer readable instruction, a data structure, a program module or other data. An example of the storage medium of the computer includes, but not limited to, a phase-change memory (PRAM), a static random access memory (SRAM), a dynamic random access memory (DRAM), other type of random access memory (RAM), a read-only memory (ROM), an electric erasable programmable read-only memory (EEPROM), a flash memory body or other internal memory technologies, a read-only optical memory(CD-ROM), a digital multifunctional optical disck (DVD) or other optical storage, a cassette-type tape, a magnetic tape magnetic disc memory or other magnetic memory device or any other non-transfer medium, available for storing the information that may be accessed by the computing device. As defined herein, the computer readable medium does not include a transient computer readable medium, e.g., modulated data signal and carrier.

[0147] It should be further noted that the terms "comprise," "include" or any other variant intends for a non-exclusive inclusion, such that a procedure, a method, a merchandise or apparatus which include a series of elements not only include those elements, but also include other elements not are not explicitly listed, or further comprise elements inherent to that process, method, merchandise or device. Without more limitations, an element limited by the statement "comprising a ..." does not exclude existence of additional identical elements in the process, method, merchandise or device that include the elements. [0148] What have been described above are only embodiments of the present disclosure, not intended to limit the present disclosure. To those skilled in the art, the present disclosure may have various modifications and changes. Any amendments, equivalent replacements and improvements made within the spirit and principle of the present disclosure should be included within the scope of the claims of the present disclosure.

Claims

I/We claim:

1. A method for controlling data packet transmission in a device-to-device communication, comprising:

obtaining, by a current user equipment, data packet priority information regarding other user equipments; and

controlling data packet transmission of the current user equipment based on the data packet priority information.

2. The method according to claim 1 ,

wherein the obtaining, by a current user equipment, data packet priority information regarding other user equipments comprises:

further obtaining, by the current user equipment, resource amount information for data packet transmission regarding the other user equipments; and

wherein the controlling data packet transmission of the current user equipment based on the data packet priority information comprises:

controlling the data packet transmission of the current user equipment based on the data packet priority information and the resource amount information.

3. The method according to claim 2, wherein the obtaining, by the current user equipment, data packet priority information and resource amount information for data packet transmission regarding other user equipments comprises:

monitoring physical side-link control channels of the other user equipments so as to obtain the data packet priority information and the resource amount information.

4. The method according to claim 2, wherein the controlling data packet transmission of the current user equipment based on the data packet priority information and the resource amount information comprises:

determining, based on the data packet priority information and the resource amount information, a network traffic load amount associated with priorities higher than the data packet priority of the current user equipment and identical to the data packet priority of the current user equipment; and

determining, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment.

5. The method according to claim 4, wherein the determining, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment comprises:

determining, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load.

6. The method according to claim 4 or 5, wherein the determining whether to continue the data packet transmission of the current user equipment based on the network traffic load comprises:

determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount.

7. The method according to claim 5, wherein the determining, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load comprises:

continuing the data packet transmission if the network traffic load amount is less than or equal to a predetermined threshold; and

further determining whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold.

8. The method according to claim 7, wherein the further determining whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold, comprises:

stopping the data packet transmission if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is higher than or equal to the predetermined threshold; and

determining whether to continue the data packet transmission based on random resource assignment processing, if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is lower than the predetermined threshold, wherein the random resource assignment processing comprises:

performing random permutation on the current user equipment and other user equipments at the same priority as the current user equipment, so as to be assigned with different random priority values;

determining, based on the random priority values, a network traffic load amount associated with the current user equipment and other user equipments having a higher priority than the data packet priority of the current user equipment;

continuing the data packet transmission if the network traffic load amount is less than or equal to an available resource amount; and

stopping the data packet transmission if the network traffic load amount is larger than the available resource amount.

9. The method according to claim 6, wherein the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises:

determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and accessing the channel to start the data packet transmission if the channel is idle.

10. The method according to claim 6, wherein the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises:

determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determining, if the channel is idle, whether to start the data packet transmission based on a back-off processing, wherein the back-off processing comprises:

determining a back-off period based on a current available resource amount and the data packet priority of the current user equipment; and

accessing the channel to start the data packet transmission if the channel continues idle during the back-off period.

11. The method according to claim 6, wherein the determining, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount comprises:

determining whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and

determining, if the channel is idle, whether to start the data packet transmission based on an access probability, comprising:

determining an access probability based on a current available resource amount and the data packet priority of the current user equipment;

generating a random number between 0 and 1 ; and

accessing the channel to start the data packet transmission if the random number is less than or equal to the access probability.

12. An apparatus for controlling data packet transmission in a device-to-device communication, comprising:

an obtaining unit configured to obtain, by a current user equipment, data packet priority information regarding other user equipments; and

a controlling unit configured to control data packet transmission of the current user equipment based on the data packet priority information.

13. The apparatus according to claim 12,

wherein the obtaining unit is further configured to obtain, by the current user equipment, resource amount information for data packet transmission regarding the other user equipments; and

wherein the controlling unit is further configured to control the data packet transmission of the current user equipment based on the data packet priority information and the resource amount information.

14. The apparatus according to claim 13, wherein the obtaining unit monitors physical side -link control channels of the other user equipments so as to obtain the data packet priority information and the resource amount information.

15. The apparatus according to claim 13, wherein the controlling unit is configured to determine, based on the data packet priority information and the resource amount information, a network traffic load amount associated with priorities higher than the data packet priority of the current user equipment and identical to the data packet priority of the current user equipment; and determine, based on the network traffic load amount, whether to perform data packet transmission for the current user equipment.

16. The apparatus according to claim 15, wherein the controlling unit is configured to determine, for ongoing data packet transmission of the current user equipment, whether to continue the data packet transmission based on the network traffic load.

17. The apparatus according to claim 15 or 16, wherein the controlling unit is configured to determine, for an arriving data packet transmission of the current user equipment, whether to start the data packet transmission based on the network traffic load amount.

18. The apparatus according to claim 16, wherein the controlling unit is configured to:

determine to continue the data packet transmission if the network traffic load amount is less than or equal to a predetermined threshold; and

further determine whether to continue the data packet transmission based on the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment, if the network traffic load amount is greater than the predetermined threshold.

19. The apparatus according to claim 18, wherein the controlling unit is configured to:

determine to stop the data packet transmission if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is higher than or equal to the predetermined threshold; and

determine whether to continue the data packet transmission based on random resource assignment processing, if the network traffic load amount associated with the priorities higher than the data packet priority of the current user equipment is lower than the predetermined threshold, wherein the random resource assignment processing comprises:

20. The apparatus according to claim 17, wherein the controlling unit is configured to:

determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and access the channel to start the data packet transmission if the channel is idle.

21. The apparatus according to claim 17, wherein the controlling unit is configured to:

determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine, if the channel is idle, whether to start the data packet transmission based on a back-off processing, wherein the back-off processing comprises:

accessing the channel to start the data packet transmission if the channel continues idle during the back-of period.

22. The apparatus according to claim 17, wherein the controlling unit is configured to:

determine whether the channel is idle based on the network traffic load amount and the resource amount information for data packet transmission of the current user equipment; and determine, if the channel is idle, whether to start the data packet transmission based on an access probability, comprising:

generating a random number between 0 and 1 ; and