Apparatus, method, and computer program

Abstract

The disclosure relates to an apparatus comprising: means for determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, N CCE, p , based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, N CCE, p , to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and means for monitoring the physical downlink control channel candidates.

Description

[0001] APPARATUS, METHOD, AND COMPUTER PROGRAM

[0002] Field of the disclosure

[0003] The present disclosure relates to techniques for determining physical downlink control channel candidates in a communication system.

[0004] Background

[0005] A communication system can be seen as a facility that enables communication sessions between two or more entities such as communication devices, base stations (BSs) and / or other nodes by providing carriers between the various entities involved in the communications path.

[0006] The communication system may be a wireless communication system. Examples of wireless systems comprise public land mobile networks (PLMN) operating based on radio standards such as those provided by 3GPP, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). The wireless systems can typically be divided into cells, and are therefore often referred to as cellular systems.

[0007] The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and / or parameters which shall be used for the connection are also typically defined. Examples of standard are 4G, 5G or 6G standards.

[0008] Summary

[0009] According to an aspect there is provided an apparatus comprising: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, / VCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, / VCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0010] The control resource set size, NCCE p, and / or the reduced control resource set size may be expressed as a number of control channel elements.

[0011] The distance between the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0012] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0013] The function may use the reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set the distance between the physical downlink control channel candidates for an aggregation level, L.

[0014] The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, ; or a maximum number of physical downlink control channel candidates, f°r anaggregation level, L, a search space, s, and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

[0015] The apparatus may comprise: determining the reduced control resource set size based on at least one of the control resource set size, NCCE p, and a value, XL.

[0016] The determining the reduced control resource set size based on the control resource set size, NCCE p,ar|d the value, XL, may comprise: determining the reduced control resource set size by subtracting the value, XL, from the control resource set size, NCCE p.

[0017] The value, XL, may be determined based on at least one of: the control resource set size, NCCE p, an aggregation level, L; a maximum number of physical downlink control channel candidates, Mg „ , for an aggregation level, L, a search space s and a carrier indicator value nCI; another control resource set size, CCEK; or a modulo function, mod. The value, XL, may be determined based on:

[0018] Xl= f 1 + mod(NCCE,p / (L x M^CI)) if mod(NCCE p / (L x M^)) < N^Ershootand NCCE.p> CCEKo otherwise

[0019] The apparatus may comprise: receiving, from a base station, the other control resource set size, CCEK.

[0020] The other control resource set size, CCEK, may be set in standards.

[0021] The other control resource set size , CCEK, may be selected by the base station amongst a set of control resource set sizes CCEKpreviously received from the base station (e.g., configured).

[0022] The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element.

[0023] The other control resource set sizes, CCEK, may be set in standards..

[0024] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0025] The apparatus may comprise: receiving, from a base station, an index, K .

[0026] The index, K , may be selected by the base station amongst a set of indexes, K , previously received from the base station (e.g., configured).

[0027] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element.

[0028] The set of indexes, K , may be set in standards.

[0029] The index, K , may be received via radio resource control signaling or via medium access control control element. The apparatus may comprise: determining the other control resource set size, CCEKbased on the index, K .

[0030] The other control resource set size CCEKmay be a first control resource set size, of a first peak of user equipment blocking probability; and the index, K , may be an index,

[0031] Alternatively, the other control resource set size, CCEK, may be a first control resource set size , CCEk of another peak of user equipment blocking probability.

[0032] A user equipment blocking probability may be defined as the probability that all the physical downlink control channel candidates monitored by a user equipment are blocked by (e.g., overlapped with) physical downlink control channel candidates allocated to other user equipment.

[0033] The user equipment blocking probability may depend on at least one of: the control resource set size, NCCE p, an aggregation level L or a number of user equipment.

[0034] The user equipment blocking probability may comprise peaks of user equipment blocking probability.

[0035] A first peak of user equipment blocking probability may be associated with a first control resource set size,’ CCEKsttart(L) .

[0036] Each subsequent peak of user equipment blocking probability may be associated with a first control resource set size .

[0037] The first control resource set size, CCE^start(L), may be dependent on at least one of: an index ,Kstart(L)<anaggregation level, L, and a maximum number , of physical downlink control channel candidates for an aggregation level L, a search space s and a carrier indicator value .nci-

[0038] Peaks of user equipment blocking probability may be separated by gaps. A gap between peaks of user equipment blocking probability may depend on at least one of: an aggregation level, L , and a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value >ncr

[0039] Each peak of user equipment blocking probability may have a number of consecutive control resource set sizes ,N^ershoot(e.g., window).

[0040] The number of consecutive control resource set sizes ,N^ershoot(e.g., window), of a peak of user equipment blocking probability may be dependent on an aggregation level ,L , (e.g., may be equal to the aggregation level ,L).

[0041] The index, Kstart(L), may be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0042] The determining control resource set size, CCEK, based on the index, K , may be based on: CCEK= is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value, nCI.

[0043] The other control resource set size, CCEK, may be a threshold control resource set size,CCEKTH ■

[0044] The threshold control resource set size, CCEKTHmay not be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0045] The function may use at least one of: a pseudo-random number, Yp nn ; a physical downlink control channel candidate index, an aggregation level, L; a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; a carrier indicator value, nc / ; a modulo function, mod; or an integer, i.

[0046] The function may be based on: mod (NCCE p- XL) / L] + i

[0047] The apparatus may be a user equipment.

[0048] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0049] The method may be performed by an apparatus.

[0050] The control resource set size, NCCE p, and / or the reduced control resource set size may be expressed as a number of control channel elements.

[0051] The distance between the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0052] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0053] The function may use the reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set the distance between the physical downlink control channel candidates for an aggregation level, L. The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, ; or a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s, and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

[0054] The method may comprise: determining the reduced control resource set size based on at least one of the control resource set size, NCCE p, and a value, XL.

[0055] The determining the reduced control resource set size based on the control resource set size, NCCE p, and the value, XL, may comprise: determining the reduced control resource set size by subtracting the value, XL, from the control resource set size, NCCE p.

[0056] The value, XL, may be determined based on at least one of: the control resource set size, NCCE p,anaggregation level, L; a maximum number of physical downlink control channel candidates, Mg „ , for an aggregation level, L, a search space s and a carrier indicator value nCI; another control resource set size, CCEK; or a modulo function, mod.

[0057] The value, XL, may be determined based on:

[0058] Xl= f 1 + mod(NCCE.p / (L x M^CI)) if mod(NCCE p / (L x M^)) < N^ershootand NCCE.p> CCEKto otherwise

[0059] The method may comprise: receiving, from a base station, the other control resource set size, CCEK.

[0060] The other control resource set size, CCEK, may be set in standards.

[0061] The other control resource set size , CCEK, may be selected by the base station amongst a set of control resource set sizes CCEKpreviously received from the base station (e.g., configured).

[0062] The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element. The other control resource set sizes, CCEK, may be set in standards..

[0063] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0064] The method may comprise: receiving, from a base station, an index, K .

[0065] The index, K , may be selected by the base station amongst a set of indexes, K , previously received from the base station (e.g., configured).

[0066] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element.

[0067] The set of indexes, K , may be set in standards.

[0068] The index, K , may be received via radio resource control signaling or via medium access control control element.

[0069] The method may comprise: determining the other control resource set size, CCEK. based on the index, K .

[0070] The other control resource set size CCEKmay be a first control resource set size, of a first peak of user equipment blocking probability; and the index, K , may be an index,Kstart( '

[0071] Alternatively, the other control resource set size, CCEK, may be a first control resource set size , CCEk ( another peak of user equipment blocking probability.

[0072] A user equipment blocking probability may be defined as the probability that all the physical downlink control channel candidates monitored by a user equipment are blocked by (e.g., overlapped with) physical downlink control channel candidates allocated to other user equipment. The user equipment blocking probability may depend on at least one of: the control resource set size, NCCE p, an aggregation level L or a number of user equipment.

[0073] The user equipment blocking probability may comprise peaks of user equipment blocking probability.

[0074] A first peak of user equipment blocking probability may be associated with a first control resource set size,’ CCEKsttart(L) .

[0075] Each subsequent peak of user equipment blocking probability may be associated with a first control resource set size .

[0076] The first control resource set size, CCE^start(L), may be dependent on at least one of: an index ,Kstart(L)<anaggregation level, L, and a maximum number , of physical downlink control channel candidates for an aggregation level L, a search space s and a carrier indicator value .nci-

[0077] Peaks of user equipment blocking probability may be separated by gaps.

[0078] A gap between peaks of user equipment blocking probability may depend on at least one of: an aggregation level , L , and a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value >nci-

[0079] Each peak of user equipment blocking probability may have a number of consecutive control resource set sizes ,N^ershoot(e.g., window).

[0080] The number of consecutive control resource set sizes ,N^ershoot(e.g., window), of a peak of user equipment blocking probability may be dependent on an aggregation level ,L , (e.g., may be equal to the aggregation level ,L).

[0081] The index, Kstart(L), may be dependent on at least one of: an aggregation level, L; or a number of user equipment. The determining control resource set size, CCEK, based on the index, K , may be based on: CCEK= is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value, nCI.

[0082] The other control resource set size, CCEK, may be a threshold control resource set size,CCEKTH ■

[0083] The threshold control resource set size, CCEKTHmay not be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0084] The function may use at least one of: a pseudo-random number, Yp nn ; a physical downlink control channel candidate index, an aggregation level, L; a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; a carrier indicator value, nc / ; a modulo function, mod; or an integer, i.

[0085] The function may be based on: mod (NCCE pXL) / L] + i

[0086] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates. According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0087] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0088] According to an aspect there is provided an apparatus comprising: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the selected physical downlink control channel candidate.

[0089] The apparatus may be a base station.

[0090] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size,NCCE,P > based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the selected physical downlink control channel candidate.

[0091] The method may be performed by an apparatus.

[0092] The apparatus may be a base station.

[0093] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the selected physical downlink control channel candidate.

[0094] According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, JVCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, / VCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the selected physical downlink control channel candidate. According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the selected physical downlink control channel candidate.

[0095] According to an aspect there is provided an apparatus comprising: means for determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and means for monitoring the physical downlink control channel candidates.

[0096] The control resource set size, NCCE p, and / or the reduced control resource set size may be expressed as a number of control channel elements.

[0097] The distance between the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0098] The function may use the reduced control resource set size smaller than the control resource set size, NCCE p, to set the distance between the physical downlink control channel candidates for an aggregation level, L.

[0099] The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, ; or a maximum number of physical downlink control channel candidates, f°r anaggregation level, L, a search space, s , and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates. The function may use the control resource set size, NCCE p, to set the control resource set p where the physical downlink control channel candidates are located.

[0100] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0101] The apparatus may comprise: means for determining the reduced control resource set size based on at least one of the control resource set size, NCCE p, and a value, XL.

[0102] The means for determining the reduced control resource set size based on the control resource set size, NCC p, and the value, XL, may comprise: means for determining the reduced control resource set size by subtracting the value, XL, from the control resource set size, NCCE p.

[0103] The value, XL, may be determined based on at least one of: the control resource set size,NCCE,P;anaggregation level, L; a maximum number of physical downlink control channel candidates, „ , for an aggregation level L, a search space s and a carrier indicator value nCI; a number of consecutive control resource set sizes of a peak of user equipment blocking probability, N^ershoot; an other control resource set size, CCEK; or a modulo function mod.

[0104] The value, XL, may be determined based on: to otherwise

[0105] The apparatus may comprise: means for receiving, from a base station, the other control resource set size, CCEK.

[0106] The other control resource set size, CCEK, may be set in standards.

[0107] The other control resource set size, CCEK, may be selected by the base station amongst a set of control resource set sizes, CCEK, previously received from the base station (e.g., configured). The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element.

[0108] The other control resource set sizes, CCEK, may be set in standards.

[0109] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0110] The apparatus may comprise: means for receiving, from a base station, an index, K .

[0111] The index, K , may be selected by the base station amongst a set of indexes K previously received from the base station (e.g., configured).

[0112] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element.

[0113] The set of indexes, K , may be set in standards.

[0114] The index, K , may be received via radio resource control signaling or via medium access control control element.

[0115] The apparatus may comprise: means for determining the other control resource set size, CCEK, based on the index, K .

[0116] The other control resource set size, CCEK, may be a first control resource set size, CCEKstart(L), of a first peak of user equipment blocking probability; and the index, K , is an index, Ks^ar^(L).

[0117] The other index Kstart(L) may be dependent on at least one of: an aggregation level, L; or a number of user equipment. The means for determining the other control resource set size, CCEK, may be based on the index, K , may be based on: where is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value, nCI.

[0118] The other control resource set size, CCEK, may be a threshold control resource set size,CCEKTH -

[0119] The threshold control resource set size, CCEKTH, may not be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0120] The function may use at least one of: a pseudo-random number, ; a physical downlink control channel candidate index, ; an aggregation level, L; a maximum number of physical downlink control channel candidates, Ms^ax, foranaggregation level, L, a search space, s , and all carrier indicator values nc / ; a carrier indicator value, nc / ; a modulo function, mod; or an integer, i.

[0121] The function may be based on: mod[(NCCE P) / L] + i

[0122] The apparatus may be a user equipment.

[0123] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates. The method may be performed by an apparatus.

[0124] The control resource set size, NCCE p, and / or the reduced control resource set size may be expressed as a number of control channel elements.

[0125] The distance between the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0126] The function may use the reduced control resource set size smaller than the control resource set size, NCCE p, to set the distance between the physical downlink control channel candidates for an aggregation level, L.

[0127] The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, ; or a maximum number of physical downlink control channel candidates, f°r anaggregation level, L, a search space, s , and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

[0128] The function may use the control resource set size, NCCE p, to set the control resource set p where the physical downlink control channel candidates are located.

[0129] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0130] The method may comprise: determining the reduced control resource set size based on at least one of the control resource set size, NCCE p, and a value, XL.

[0131] The determining the reduced control resource set size based on the control resource set size,NCCE,P> and the value, XE, may comprise: determining the reduced control resource set size by subtracting the value, XL, from the control resource set size, NCCE p.

[0132] The value, XL, may be determined based on at least one of: the control resource set size,NCCE,P;anaggregation level, L; a maximum number of physical downlink control channel candidates, , for an aggregation level L, a search space s and a carrier indicator value nCI; a number of consecutive control resource set sizes of a peak of user equipment blocking probability, N^ershoot; an other control resource set size, CCEK; or a modulo function mod.

[0133] The value, XL, may be determined based on:

[0134] XL= [ 1 + mod( to otherwise

[0135] The method may comprise: receiving, from a base station, the other control resource set size, CCEK.

[0136] The other control resource set size, CCEK, may be set in standards.

[0137] The other control resource set size, CCEK, may be selected by the base station amongst a set of control resource set sizes, CCEK, previously received from the base station (e.g., configured).

[0138] The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element.

[0139] The other control resource set sizes, CCEK, may be set in standards.

[0140] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0141] The method may comprise: receiving, from a base station, an index, K .

[0142] The index, K , may be selected by the base station amongst a set of indexes K previously received from the base station (e.g., configured).

[0143] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element. The set of indexes, K , may be set in standards.

[0144] The index, K , may be received via radio resource control signaling or via medium access control control element.

[0145] The method may comprise: determining the other control resource set size, CCEK, based on the index, K .

[0146] The other control resource set size, CCEK, may be a first control resource set size, CCEKstart(L), of a first peak of user equipment blocking probability; and the index, K , is an index, Kstart(L).

[0147] The other index Kstart(L) may be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0148] The determining the other control resource set size, CCEK, may be based on the index, K , may be based on: where is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space, s , and a carrier indicator value, nCi.

[0149] The other control resource set size, CCEre, may be a threshold control resource set size,CCEKTH -

[0150] The threshold control resource set size, CCEKTH, may not be dependent on at least one of: an aggregation level, £; or a number of user equipment.

[0151] The function may use at least one of: a pseudo-random number, ; a physical downlink control channel candidate index, ; an aggregation level, L\ a maximum number of physical downlink control channel candidates, AfJmax, for an aggregation level, L, a search space, s , and all carrier indicator values nC{; a carrier indicator value, nC{; a modulo function, mod; or an integer, i.

[0152] The function may be based on:

[0153] The apparatus may be a user equipment.

[0154] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0155] According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0156] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates. According to an aspect there is provided an apparatus comprising: means for determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and means for allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and means for transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0157] The apparatus is a base station.

[0158] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size,NCCE,P> based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0159] The method may be performed by an apparatus.

[0160] The apparatus is a base station.

[0161] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0162] According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, JVCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0163] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0164] According to an aspect there is provided an apparatus comprising: means for determining physical downlink control channel candidates to monitor within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and means for monitoring the physical downlink control channel candidates.

[0165] In this disclosure, the expressions “setting an offset” and “setting the value of an offset” may be used interchangeably.

[0166] In this disclosure, the terms “offset” and “shift” may be used interchangeably. The function may use the value, Xm L, to set an offset for only one physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0167] The function may use the value, Xm L, to set an offset for a last physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0168] The control resource set, p , may have a control resource set size, NCCE p, and the function uses the control resource set size, NCCE p, to set a distance between physical downlink control channel candidates other than the at least one physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0169] The control resource set size, NCCE pand / or the reduced control resource set size may be expressed as a number of control channel elements.

[0170] The distance between physical downlink control channel candidates other than the at least one physical downlink control channel candidate amongst the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0171] The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, ; or a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

[0172] The function may use the control resource set size, NCCE p, to set the control resource set, p , where the physical downlink control channel candidates are located.

[0173] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0174] The value, Xm L, may be determined based on at least one of: the control resource set size, NCCE p,anaggregation level, L; a physical downlink control channel candidate index, ;a maximum number of physical downlink control channel candidates, , for an aggregation level, L, a search space, s , and a carrier indicator value, nCI; a number of consecutive control resource set sizes of a peak of user equipment blocking probability, N^ershoot; another control resource set size, CCEK; or a modulo function ,mod.

[0175] The value Xm Lmay be determined based on: to otherwise

[0176] The apparatus may comprise: means for receiving, from a base station, the control resource set size, CCEK,.

[0177] The other control resource set size, CCEK, may be set in standards.

[0178] The other control resource set size, CCEK, may be selected by the base station amongst a set of control resource set sizes, CCEK, previously received from the base station (e.g., configured).

[0179] The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element.

[0180] The other control resource set sizes, CCEK, may be set in standards.

[0181] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0182] The apparatus may comprise: means for receiving, from a base station, an index, K .

[0183] The index, K , may be selected by the base station amongst a set of indexes, K , previously received from the base station (e.g., configured).

[0184] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element.

[0185] The set of indexes, K , may be set in standards. The index, K , may be received via radio resource control signaling or via medium access control control element.

[0186] The apparatus may comprise: means for determining the other control resource set size, CCEK, based on the index, K .

[0187] The other control resource set size, CCEK, may be a first control resource set size, of a first peak of user equipment blocking probability; and the index, K , may be an index, Kstart(L)-

[0188] The index, Kstart(L), may be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0189] The means for determining the other control resource set size, CCEK, based on the index,

[0190] K , is based on: CCEK= = Kstart(L) J x L x Msnr, where is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space s and a carrier indicator value, nCI.

[0191] The other control resource set size, CCEK, may be a threshold control resource set size,CCEKTH-

[0192] The threshold control resource set size, CCEKTH, may not be dependent on at least one of: an aggregation level, £; or a number of user equipment.

[0193] The function may use at least one of: a pseudo-random number, Yp nn ; a physical downlink control channel candidate index, ; an aggregation level, L; a maximum number of physical downlink control channel candidates, Ms^ax, foranaggregation level, L, a search space, s , and all carrier indicator values, nCI; a carrier indicator value, nc / ; a modulo function, mod; or an integer, i.

[0194] The function may be based on:

[0195] The apparatus may be a user equipment.

[0196] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates to monitor within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0197] The method may be performed by an apparatus.

[0198] In this disclosure, the expressions “setting an offset” and “setting the value of an offset” may be used interchangeably.

[0199] In this disclosure, the terms “offset” and “shift” may be used interchangeably.

[0200] The function may use the value, Xm L, to set an offset for only one physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0201] The function may use the value, Xm L, to set an offset for a last physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0202] The control resource set, p , may have a control resource set size, NCCE p, and the function uses the control resource set size, NCCE p, to set a distance between physical downlink control channel candidates other than the at least one physical downlink control channel candidate amongst the physical downlink control channel candidates.

[0203] The control resource set size, NCCE pand / or the reduced control resource set size may be expressed as a number of control channel elements. The distance between physical downlink control channel candidates other than the at least one physical downlink control channel candidate amongst the physical downlink control channel candidates may be expressed as a number of control channel elements.

[0204] The function may use at least one of: an aggregation level, L; a physical downlink control channel candidate index, m^ci; or a maximum number of physical downlink control channel candidates, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

[0205] The function may use the control resource set size, NCCE p, to set the control resource set, p , where the physical downlink control channel candidates are located.

[0206] The location of a physical downlink control channel candidate may be expressed as an index of a control channel element.

[0207] The value, Xm L, may be determined based on at least one of: the control resource set size, NCCE p,anaggregation level, L; a physical downlink control channel candidate index, ;a maximum number of physical downlink control channel candidates, , for an aggregation level, L, a search space, s , and a carrier indicator value, nCI; a number of consecutive control resource set sizes of a peak of user equipment blocking probability, N^ershoot; another control resource set size, CCEK; or a modulo function ,mod.

[0208] The value Xm Lmay be determined based on: to otherwise

[0209] The method may comprise: receiving, from a base station, the control resource set size, CCEK).

[0210] The other control resource set size, CCEK, may be set in standards. The other control resource set size, CCEK, may be selected by the base station amongst a set of control resource set sizes, CCEK, previously received from the base station (e.g., configured).

[0211] The other control resource set sizes, CCEK, may be received via radio resource control signaling or via a SearchSpace information element.

[0212] The other control resource set sizes, CCEK, may be set in standards.

[0213] The other control resource set size, CCEK, may be received via radio resource control signaling or via medium access control control element.

[0214] The method may comprise: receiving, from a base station, an index, K .

[0215] The index, K , may be selected by the base station amongst a set of indexes, K , previously received from the base station (e.g., configured).

[0216] The set of indexes, K , may be received via radio resource control signaling or via a SearchSpace information element.

[0217] The set of indexes, K , may be set in standards.

[0218] The index, K , may be received via radio resource control signaling or via medium access control control element.

[0219] The method may comprise: determining the other control resource set size, CCEK, based on the index, K .

[0220] The other control resource set size, CCEK, may be a first control resource set size, CCEKstart(L), of a first peak of user equipment blocking probability; and the index, K , may be an index, Kstart(L)- The index, Kstart(L), may be dependent on at least one of: an aggregation level, L; or a number of user equipment.

[0221] The determining the other control resource set size, CCEK, based on the index, K , is based on: CCEK= whereL„C[is a maximum number of physical downlink control channel candidates for an aggregation level, L, a search space s and a carrier indicator value, nCI.

[0222] The other control resource set size, CCEK, may be a threshold control resource set size,CCE«™-

[0223] The threshold control resource set size, CCEKTH, may not be dependent on at least one of: an aggregation level, ; or a number of user equipment.

[0224] The function may use at least one of: a pseudo-random number, ; a physical downlink control channel candidate index, m^C[; an aggregation level, L; a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; a carrier indicator value, nCI; a modulo function, mod; or an integer, i.

[0225] The function may be based on:

[0226] The apparatus may be a user equipment.

[0227] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates to monitor within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates. According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates to monitor within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0228] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates to monitor within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

[0229] According to an aspect there is provided an apparatus comprising: means for determining physical downlink control channel candidates within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and means for allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and means for transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0230] The apparatus may be a base station.

[0231] According to an aspect there is provided a method comprising: determining physical downlink control channel candidates within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and r transmitting the physical downlink control channel on the allocated physical downlink control channel candidate. The method may be performed by an apparatus.

[0232] The apparatus may be a base station.

[0233] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining physical downlink control channel candidates within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and r transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0234] According to an aspect there is provided an apparatus comprising circuitry configured to perform: determining physical downlink control channel candidates within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and r transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0235] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: determining physical downlink control channel candidates within a control resource set, p , based on a function, wherein the function uses a value, Xm L, to set on offset for at least one physical downlink control channel candidate amongst the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and r transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

[0236] According to an aspect, there is provided a computer readable medium comprising program instructions stored thereon for performing at least one of the above methods. According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

[0237] According to an aspect, there is provided a non-volatile tangible memory medium comprising program instructions stored thereon for performing at least one of the above methods.

[0238] In the above, many different aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the aspects described above.

[0239] Various other aspects are also described in the following detailed description and in the attached claims.

[0240] List of abbreviations

[0241] AF: Application Function

[0242] AL: Aggregation Level

[0243] AMF: Access and Mobility Management Function

[0244] BS: Base Station

[0245] CCE: Control Channel Element

[0246] CSS: Common Search Space

[0247] CORESET: Control Resource Set

[0248] CU: Centralized Unit

[0249] DCI: Downlink Control Information

[0250] DL: Downlink

[0251] DU: Distributed Unit gNB: gNodeB

[0252] IE: Information Element loT: Internet of Things

[0253] LTE: Long Term Evolution

[0254] MIB : Master Information Block MS: Mobile Station

[0255] MTC: Machine Type Communication

[0256] NEF: Network Exposure Function

[0257] NF: Network Function

[0258] NR: New radio

[0259] NRF: Network Repository Function

[0260] OFDM: Orthogonal Frequency Division Multiplexing

[0261] PLMN: Public Land Mobile Network

[0262] PLICCH: Physical Uplink Control Channel

[0263] PUSCH: Physical Uplink Shared Channel

[0264] PDCCH: Physical Downlink Control Channel

[0265] RAM: Random Access Memory

[0266] (R)AN: (Radio) Access Network

[0267] RACH: Random Access Channel

[0268] RB: Resource Block

[0269] REG: Resource Element Group

[0270] ROM: Read Only Memory

[0271] SIB: System Information Block

[0272] SSB: Synchronisation Signal Block

[0273] UE: User Equipment

[0274] USS: User Equipment specific Search Space

[0275] 4G: 4thGeneration

[0276] 5G: 5thGeneration

[0277] 5GC: 5G Core network

[0278] 5GS: 5G System

[0279] 6G: 6thGeneration

[0280] Brief Description of the Figures

[0281] Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

[0282] Fig. 1 shows a schematic representation of an example 5G system;

[0283] Fig. 2 shows a schematic representation of an example control apparatus; Fig. 3 shows a schematic representation of an example user equipment;

[0284] Fig. 4 shows an example of physical downlink control channel candidates for a user equipment;

[0285] Fig. 5 shows an example of physical downlink control channel candidates for ten user equipment;

[0286] Fig. 6 shows an example of a graph of a user equipment blocking probability as a function of a control resource set size for an aggregation level one and for a number of user equipment equal to ten, twenty, thirty and forty and an overall user equipment blocking probability as a function of a control resource set size for a number of user equipment equal to ten, twenty, thirty and forty calculated for an existing hashing function;

[0287] Fig. 7 shows an example of a graph of a user equipment blocking probability as a function of a control resource set size for an aggregation level two and for a number of user equipment equal to ten, twenty, thirty and forty and an overall user equipment blocking probability as a function of a control resource set size for a number of user equipment equal to ten, twenty, thirty and forty calculated for an existing hashing function;

[0288] Fig. 8 shows an example of a graph of a user equipment blocking probability for an existing hashing function as a function of a control resource set size for an aggregation level four and for a number of user equipment equal to ten, twenty, thirty and forty and an overall user equipment blocking probability as a function of a control resource set size for a number of user equipment equal to ten, twenty, thirty and forty calculated for an existing hashing function;

[0289] Fig.9a and Fig.9b shows an example of a signaling diagram of a method for determining physical downlink control channel candidates;

[0290] Fig. 10a shows an example of a graph of a user equipment blocking probability as a function of a control resource set size for an aggregation level one and for a number of user equipment equal to thirty calculated for an existing hashing function and hashing functions according to a first solution, a second solution and a third solution;

[0291] Fig. 10b shows an example of a graph of a user equipment blocking probability as a function of a control resource set size for an aggregation level two and for a number of user equipment equal to twenty calculated for an existing hashing function and hashing functions according to a first solution, a second solution and a third solution;

[0292] Fig. 11a shows an example of a graph of an overall user equipment blocking probability as a function of a control resource set size for a number of user equipment equal to fifteen calculated for an existing hashing function and hashing functions according to a first solution, a second solution and a third solution;

[0293] Fig. 11b shows an example of a graph of an overall user equipment blocking probability as a function of a control resource set size for a number of user equipment equal to twenty five calculated for an existing hashing function and hashing functions according to a first solution, a second solution and a third solution;

[0294] Fig. 12 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a first solution performed by the user equipment;

[0295] Fig. 13 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a first solution performed by a base station;

[0296] Fig. 14 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a second solution performed by the user equipment;

[0297] Fig. 15 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a second solution performed by a base station;

[0298] Fig. 16 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a third solution performed by the user equipment;

[0299] Fig. 17 shows a block diagram of an example of a method for determining physical downlink control channel candidates according to a third solution performed by a base station; and

[0300] Fig. 18 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the method of any of Fig. 12 to Fig. 17. Detailed Description of the Figures

[0301] In the following certain embodiments are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Fig. 1 , Fig.2 and Fig.3 to assist in understanding the technology underlying the described examples.

[0302] FIG. 1 shows a schematic representation of an example 5G system (5GS). The 5GS may comprises user equipment (UEs), a (radio) access network ((R)AN), a 5G core network (5GC), one or more application functions (AF) and one or more data networks (DN).

[0303] The 5G (R)AN may comprise one or more base stations (BSs). The one or more BSs may comprise one or more gNodeBs (gNBs). The gNodeBs may comprise one or more gNB distributed unit functions connected to one or more gNB centralized unit functions.

[0304] The gNodeBs may comprise activator gNodeBs, reader gNodeBs or activator and reader gNodeBs.

[0305] The 5GC may comprise an access and mobility management function (AMF), a session management function (SMF), an authentication server function (ALISF), a user data management (UDM), a user plane function (UPF), a network exposure function (NEF).

[0306] It will be understood that although solutions for determining physical downlink control channel (PDCCH) candidates are discussed in the context of a 5GS, these solutions may be used with other communication systems, in particular a 6GS.

[0307] It will be understood that other communication systems, in particular a 6GS, may comprise some or all of the components of a 5GS.

[0308] Fig. 2 illustrates an example of a control apparatus 200 for controlling a function of the (R)AN or the 5GC as illustrated on Fig. 1. The control apparatus may comprise at least one random access memory (RAM) 211a, at least on read only memory (ROM) 211b, at least one processor 212, 213 and an input / output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5G (R)AN or the 5GC. In some embodiments, each function of the (R)AN or the 5GC comprises a control apparatus 200. In alternative embodiments, two or more functions of the (R)AN or the 5GC may share a control apparatus.

[0309] Fig. 3 illustrates an example of a user equipment 300, such as the user equipment illustrated on Fig. 1 . The UE 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, an Internet of things (loT) device or any combinations of these or the like. The UE 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

[0310] The UE 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Fig. 3 transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0311] The UE 300 may be provided with at least one processor 301 , at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 302a. The processor, storage and other relevant control apparatus can be provided on an appropriate circuit board and / or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as keypad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

[0312] A BS may schedule a physical uplink shared channel (PLISCH) and a physical downlink shared channel (PDSCH) by transmitting a physical downlink control channel (PDCCH) to a UE. The PDCCH may convey downlink control information (DCI) comprising information for transmission of PLISCH by the UE and reception of PDSCH by the UE.

[0313] Unlike PUSCH and PDSCH, the BS may not schedule the PDCCH by transmitting a channel to the UE. The UE may perform blind decoding of PDCCH candidates in a search space associated with a control resource set (CORESET). The CORESET may span over one, two, or three contiguous orthogonal frequency-division multiplexing (OFDM) symbols and over multiple resource blocks (RBs). A RB may comprise twelve subcarriers.

[0314] The search space may comprise PDCCH candidates. Each PDCCH candidate may comprise one, two, four, eight or sixteen control channel elements (CCEs). The number of CCEs may be defined by an aggregation level (AL). A CCE may comprise six resource element groups (REGs). A REG may comprise twelve resource elements (REs) in one OFDM symbol. A CCE may be identified by a CCE index. The search space may comprise a common search space (CSS) commonly monitored by a group of UEs or a UE-specific search space (USS) monitored by a specific UE.

[0315] The BS may allocate a PDCCH candidate amongst the PDCCH candidates.

[0316] The BS may transmit the PDCCH on the allocated PDCCH candidate

[0317] Fig. 4 shows an example of PDCCH candidates for a UE. Here, the CORESET comprises sixty-four CCEs. The search space of the UE comprises six PDCCH candidates. Each PDCCH candidate comprises one CCE (i.e. , aggregation level one). The PDCCH candidates over which a UE is expected to perform the blind decoding may be determined by a hashing function. A criterion for the design of the hashing function is the UE blocking probability and / or the overall UE blocking probability.

[0318] The UE blocking probability may refer to the probability that all PDCCH candidates monitored by a UE are blocked by (e.g., overlap with) PDCCH candidates allocated to other UEs so that the UE cannot receive the PDCCH, when each PDCCH candidate monitored by the UE comprises a specific number of CCEs (i.e. , specific aggregation level).

[0319] The overall UE blocking probability may refer to the probability that all PDCCH candidates monitored by a UE are blocked by (e.g., overlap with) PDCCH candidates allocated to other UEs so that the PDCCH for the UE cannot be transmitted, when each PDCCH candidate monitored by the UE comprise any number of CCEs (i.e., any aggregation level). The overall UE blocking probability may be an average of all UE blocking probabilities of a serving cell.

[0320] Fig. 5 shows an example of PDCCH candidates for ten UEs. Here, the CORESET comprises sixty-four CCEs. The search space of a UE2 comprises one PDCCH candidate. The PDCCH candidate comprises sixteen CCEs (i.e., aggregation level sixteen). The search space of a UE5 comprises two PDCCH candidates. Each PDCCH candidate comprises eight CCEs (i.e., aggregation level eight). The PDCCH candidate of the UE2 is blocked by a PDCCH candidate allocated to the UE5. The PDCCH cannot be transmitted for UE2.

[0321] Likewise, the search space of a UE8 comprises one PDCCH candidate. The PDCCH candidate comprises sixteen CCEs (i.e., aggregation level sixteen). The search space of a UE9 comprises two PDCCH candidates. Each PDCCH candidate comprises eight CCEs (i.e., aggregation level eight). The PDCCH candidate of the UE8 is blocked by a PDCCH candidate allocated to the UE9. The PDCCH cannot be transmitted for UE8.

[0322] The hashing function may be designed to reduce or minimize the UE blocking probability.

[0323] An existing hashing function is defined in 3GPP TS 38.123 (clause 10.1) as follows.

[0324] MsLnclmay be configured via radio resourse signaling. may be configured via a SearchSpace information element (IE).

[0325] The LIE blocking probability calculated for the existing hashing function may depend on a CORESET size, an aggregation level and / or a number of (scheduled) UEs.

[0326] Fig. 6 shows an example of a graph of a LIE blocking probability as a function of a CORESET size for an aggregation level one and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty and an overall UE blocking probability as a function of a CORESET size for a number of (scheduled) UEs equal to ten, twenty, thirty and forty calculated for the existing hashing function.

[0327] Fig. 7 shows an example of a graph of a UE blocking probability as a function of a CORESET size for an aggregation level two and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty and an overall UE blocking probability as a function of a CORESET size for a number of (scheduled) UEs equal to ten, twenty, thirty and forty calculated for an existing hashing function. Fig. 8 shows an example of a graph of a UE blocking probability as a function of a CORESET size for an aggregation level four and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty and an overall UE blocking probability as a function of a CORESET size for a number of (scheduled) UEs equal to ten, twenty, thirty and forty calculated for an existing hashing function. pmf_AL may refer to a probability mass function for aggregation level [1 ,2,4,8,16] and M_AL may refer to a number of PDCCH candidates for aggregation level [1 ,2,4,8,16],

[0328] As can be seen, the UE blocking probability may significantly increase for certain CORESET sizes. In other words, the UE blocking probability may comprise peaks of UE blocking probability for certain CORESET sizes.

[0329] In this disclosure, the expression “peak” or “overshoot” may be used interchangeably.

[0330] For example, for aggregation level one and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty (see Fig. 6), the UE blocking probability may comprise a peak of UE blocking probability for a CORESET size equal to thirty-six CCEs.

[0331] For aggregation level two and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty (see Fig. 7), the UE blocking probability may comprise a peak of UE blocking probability for a CORESET size equal to twenty-six CCEs and twenty-seven CCEs.

[0332] For aggregation level four and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty (see Fig. 7), the UE blocking probability may comprise a peak of UE blocking probability for a CORESET size equal to forty-eight CCEs, forty-nine CCEs, fifty CCEs and fifty-one CCEs.

[0333] Aggregation level one, two and four may be the most used aggregation levels. However, other aggregation levels (e.g., three, five, seven, eight or sixteen) may be used as well and the same behaviour may be observed.

[0334] One or more aspect of this disclosure relates to providing a new hashing function to determine PDCCH candidates within a CORESET p with a CORESET size NCCE p. One or more aspect of this disclosure relates to providing a new hashing function that reduces or minimizes peaks in UE blocking probability and / or in overall UE blocking probability.

[0335] In this disclosure, the expression “hashing function” or “function” may be used interchangeably.

[0336] Preliminary observation

[0337] As explained above, the UE blocking probability calculated for the existing hashing function may comprise peaks of UE probability.

[0338] Each peak of UE blocking probability may have a number of consecutive CORESET sizesNovershoot (e9 > window). The number of consecutive CORESET sizes N^ershoot(e.g., window) of a peak of UE blocking probability may be dependent on an aggregation level L. The number of consecutive CORESET sizes N^ershootof a peak of UE blocking probability may be based on: iq oWvershoot = L

[0339] Peaks of UE blocking probability may be separated by gaps CCE^, (e.g., steps). A gap CCEggp between peaks of UE blocking probability may be expressed as a number of CCEs. A gap CCEggp between peaks of UE blocking probability may depend on at least one of: an aggregation level L and a maximum number of PDCCH candidates an aggregation level L, a search space s and a carrier indicator value nCI. A gap CCEggpbetween peaks of UE blocking probability may be based on:

[0340] CCEgi = L x M®,

[0341] Each peak of UE blocking probability may be associated with a single CORESET size or with multiple consecutive CORESET sizes. A first peak of UE blocking probability may be associated with a first CORESET size and / or consecutive CORESET sizesCCEKstart+i(L)- -C C EKstart+L-i(L)■ Each subsequent peak of UE blocking probability may be associated with a first CORESET size CCEK(L)and / or consecutive CORESET sizes CCEK+1(L), ... CCEK+L-1(L). The first CORESET sizes may be expressed as a number of CCEs. The first CORESET size CCEKstart(L)may be dependent on a number of (scheduled) UEs. The first CORESET size may be dependent on at least one of: an index KKS , an aggregation level L and a maximum number of PDCCH candidates for an aggregation level L , a search space s and a carrier indicator value nCI. The first CORESET size CCE*Ks „tart(L) mayJbe based on:

[0342] For example, for aggregation level one and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty (see Fig. 6), the first CORESET size CCEKstart(L)may be twelve CCEs, eighteen CCEs, twenty-four CCEs and thirty CCEs. Therefore, the index KKstart(L)may be two, three, four and five.

[0343] First solution

[0344] The hashing function may be based on pseudo-random number Ypindex m^CI, a reduced CORESET size smaller than the CORESET size NCCE p, an aggregation level L, a maximum number of PDCCH candidates Af^aXfor an aggregation level L, a search space s and all carrier indicator values nCI, a carrier indicator value nCI, a modulo function mod and / or an integer i.

[0345] The hashing function may use a reduced CORESET size smaller than the CORESET sizeNCCE,P and / or an aggregation level L to set a portion of the CORESET p where the PDCCH candidates are located.

[0346] It will be understood that the CORESET size NCCE pand / or the reduced CORESET size may be expressed as a number of CCEs.

[0347] It will be understood that the location of a PDCCH candidate may be expressed as an index of a CCE. The hashing function may use a PDCCH index m^CI, the reduced CORESET size smaller than the CORESET size NCCE p, an aggregation level !, and / or or a maximum number of PDCCH candidates Afs(maxfor anaggregation level L, a search space s and all carrier indicator values nCIto set the distance between the PDCCH candidates.

[0348] It will be understood that the distance between the PDCCH candidates may be expressed as a number of CCEs.

[0349] The hashing function may be based on: where, for example: for any for a 39827 for pmod3 = 0 , Ap= 39829 for pmod3 = 1 , Ap= 39839 for pmod3 = 2 , and D = 65537; i = 0, -,L - 1;

[0350] NCCE pis the number of CCES, numbered from O to NCCE p- 1, in CORESET p and, if any, per RB set; nci is

[0351] - the carrier indicator field value, if provided by cif-lnSchedulingCell in CrossCarrierSchedulingConfig for the serving cell on which PDCCH is monitored, except for scheduling of the serving cell from the same serving cell in which case nci = 0;

[0352] - the nCI-Value, if provided, for the set of serving cells MC-DCI-SetofCells;

[0353] - otherwise, including for any CSS, nCI= 0 >1> where Af®ris the number of PDCCH candidates the UE is configured to monitor for aggregation level L of a search space set s for a serving cell corresponding to nCI\ for any J for a USS, Afj^axisthe maximum over all configured nCIvalues for a

[0354] CCE aggregation level L of search space set s ; the RNTI value used for nRNTIis the C-RNTI.

[0355] The reduced CORESET size may be obtained by subtracting a parameter XLfrom the CORESET size NCCE p.

[0356] The parameter XLmay be based on a modulo function mod, a CORESET size NCCE pof a CORESET p, an aggregation level L, a maximum number of PDCCH candidates M^c / for an aggregation level L , a search space s and a carrier indicator values nCI, a number of consecutive CORESET sizes N^ershootof a peak of UE blocking probability and / or CORESET size CCEK.

[0357] It will be understood that the CORESET size CCEKmay be different from the CORESET sizeNCCE,P°f the CORESET p. The CORESET size CCEremay be smaller than the CORESET size NCCE pof the CORESET p.

[0358] As will be apparent below the CORESET size CCEKmay comprise the first CORESET size associated with the first peak of UE blocking probability. Alternatively, the

[0359] CORESET size CCEKmay comprise a threshold CORESET size CCEKrH.

[0360] The parameter XLmay be equal to or greater than one.

[0361] The parameter XLmay be determined so that the reduced CORESET size is the largest CORESET size not resulting in a peak in UE blocking capability.

[0362] For example, for aggregation level one and for a number of (scheduled) UEs equal to ten, twenty, thirty and forty (see Fig. 6), the first CORESET size CCEKstart(L)may be twelve CCEs, eighteen CCEs, twenty-four CCEs and thirty CCEs. Therefore, the parameter XLmay be determined so that the reduced CORESET size is eleven CCEs. Seventeen CCEs, twenty- three CCEs and twenty-nine CCEs. The parameter XLmay be determined so that the reduced CORESET size is smaller than the largest CORESET size not resulting in a peak in UE blocking capability. However, the smaller the reduced CORESET size the larger the UE block probability (i.e. , the reduced CORESET size may be unnecessarily small limiting the number of CCEs for locating PDCCH candidates).

[0363] The parameter XLmay be based on:

[0364] X] =[ 1 + rnod( if mod(

[0365] 10 otherwise

[0366] In an implementation, the CORESET size CCEKmay comprise the first CORESET size CCEKstart(L)associated with the first peak of UE blocking probability.

[0367] The UE may receive, from the BS, the first CORESET size CCE^start(.L. . The UE may determine the parameter XLbased on the first CORESET size . The first CORESET size may be received via RRC signalling or MAC CE. The first CORESET size may selected amongst a set (e.g., group or range) of first CORESET sizes . The set of first CORESET sizes may be previously received from the

[0368] BS (e.g., configured). The set of first CORESET sizes CCE^start(L)may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of first CORESET sizes CCE* •'■s „tart(L) mayJbe set in the standards.

[0369] Alternatively, the UE may receive, from the BS, the index KKstar The UE may determine the first CORESET size CCE* •'■s „tart(L) based on the index KKKs „tart(L) The UE mayJdetermine the first

[0370] CORESET size CCEj •'i■star „t(L) based on:

[0371] CCEKK= CCE Kt-start _fL) = Ks stLadritL

[0372] The UE may determine the parameter XLbased on the first CORESET size CCE^start(L). The index Kstart(L) may be received via RRC signalling or MAC CE. The index Kstart(L) may be selected amongst a set (e.g., group or range) of indexes Kstart(E)- The index Kstart(L)may be dependent on an aggregation level L and / or a number of (scheduled) UEs. The set of indexes

[0373] Kstart(L) may be previously received from the BS (e.g., configured). The set of first indexesKstart(L) may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of indexes Kstart(L) may be set in the standards.

[0374] Alternatively, the UE may not receive, from the BS, the first CORESET size CCEKstart(L)or the index KstartCL). The first CORESET size CCE^siart(L)may be set in the standards. The UE may determine the parameter XLbased on the first CORESET size CCEKstart(L).

[0375] In another implementation, the CORESET size CCEKmay comprise a threshold CORESET size CCEKTH.

[0376] The UE may receive, from the BS, a CORESET size CCEKTH. The UE may determine the parameter XLbased on the CORESET size CCEKTH. The CORESET size CCEKTHmay be set in the standards.

[0377] Alternatively, the UE may not receive, from the BS, the CORESET size CCEKTH. The CORESET size CCEKTHmay be set in the standards. The UE may determine the parameter XLbased on the CORESET size CCEKTH.

[0378] A UE may determine PDCCH candidates to monitor within a CORESET p with a CORESET size NCCE pbased on the hashing function.

[0379] Determining PDCCH candidates may comprise determining locations of PDCCH candidates (i.e. , determining CCE indexes of PDCCH candidates).

[0380] The UE may monitor the PDCCH candidates.

[0381] The UE may receive a PDCCH on an allocated PDCCH candidate amongst the PDCCH candidates.

[0382] Second solution The hashing function may be based on pseudo-random number Yp nu index m^CI>areduced CORESET size smaller than the CORESET size NCCE p, an aggregation level L, a maximum number of PDCCH candidates Ms(maXf°r anaggregation level L , a search space s and all carrier indicator values ncl, a carrier indicator value ncl, a modulo function mod and / or an integer i.

[0383] The hashing function may use the CORESET size NCCE pand / or an aggregation level L to set the CORESET p where the PDCCH candidates are located.

[0384] It will be understood that the CORESET size NCCE pand / or the reduced CORESET size may be expressed as a number of CCEs.

[0385] It will be understood that the location of a PDDCH candidate may be expressed as an index of a CCE.

[0386] The hashing function may use a PDCCH index m^CI, the reduced CORESET size smaller than the CORESET size NCCE p, an aggregation level L, and / or or a maximum number of PDCCH candidates an aggregation level L, a search space s and all carrier indicator values nCIto set the distance between the PDCCH candidates.

[0387] It will be understood that the distance between the PDCCH candidates may be expressed as a number of CCEs.

[0388] The hashing function may be based on: where, for example: for any for a 39827 for pmod3 = 0 , Ap= 39829 for pmod3 = 1 , Ap= 39839 for pmod3 = 2 , and D = 65537; i = 0, - , L - 1;

[0389] NCCE pis the number of CCES, numbered from O to NCCE p- 1, in CORESET p and, if any, per RB set; nci is

[0390] - the carrier indicator field value, if provided by cif-lnSchedulingCell in CrossCarrierSchedulingConfig for the serving cell on which PDCCH is monitored, except for scheduling of the serving cell from the same serving cell in which case na = 0;

[0391] - the nCI-Value, if provided, for the set of serving cells MC-DCI-SetofCells;

[0392] - otherwise, including for any CSS, nCI= 0 m¥nCi= 'MsLnCI~ 1> where MsLnclis the number of PDCCH candidates the UE is configured to monitor for aggregation level L of a search space set s for a serving cell corresponding to nc / ; for any for a USS, Afj^axis the maximum over all configured nCIvalues for a CCE aggregation level L of search space set s ; the RNTI value used for nRNTIis the C-RNTI.

[0393] The reduced CORESET size may be obtained by subtracting a parameter XLfrom the CORESET size NCCE p.

[0394] The parameter XLmay be based on a modulo function mod, a CORESET size NCCE pof a CORESET p, an aggregation level L, a maximum number of PDCCH candidates for an aggregation level L , a search space s and a carrier indicator values nCI, a number of consecutive CORESET sizes N^ershootof a peak of UE blocking probability and / or CORESET size CCEK.

[0395] It will be understood that the CORESET size CCEremay be different from the CORESET size NCCE p°f the CORESET p. The CORESET size CCEKmay be smaller than the CORESET size NCCE pof the CORESET p. As will be apparent below the CORESET size CCEKmay comprise the first CORESET size S ,tart(L) associated with the first peak of UE blocking probability. Alternatively, the

[0396] CORESET size CCEKmay comprise a threshold CORESET size CCEK7.H.

[0397] The parameter XLmay be based on:

[0398] XL= I1+ mod( if mod( / VCCE,p / (£ x M^a)) < N^ershootand NCCEIP> CCEK

[0399] 10 otherwise

[0400] In an implementation, the CORESET size CCEKmay comprise the first CORESET size CCEKstart(L)associated with the first peak of UE blocking probability.

[0401] The UE may receive, from the BS, the first CORESET size CCE^start(L). The UE may determine the parameter XLbased on the first CORESET size CCE^start(L). The first CORESET size may be received via RRC signalling or MAC CE. The first CORESET size selected amongst a set (e.g., group or range) of first CORESET sizes . The set of first CORESET sizes may be previously received from the

[0402] BS (e.g., configured). The set of first CORESET sizes CCE^start(L)may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of first CORESET sizes CCE*Ks „tart(L) mayJbe set in the standards.

[0403] Alternatively, the UE may receive, from the BS, the index KKstar The UE may determine the first CORESET size CCE*Ks „tart(L) based on the index KKKs „tart(L) The UE mayJdetermine the first

[0404] CORESET size CCE^Kstart(L) based on:

[0405] CCEK= CCE^Ks ,tarttn(L) = Ks stLadritL(kL) y X L X M^ s,nci,

[0406] The UE may determine the parameter XLbased on the first CORESET size CCE^start(L). The index Kstart(L) may be received via RRC signalling or MAC CE. The index Kstart(L) may be selected amongst a set (e.g., group or range) of indexes Kstart(L). The index KKstarl(L. may be dependent on an aggregation level L and / or a number of (scheduled) UEs. The set of indexes Kstart(L) may be previously received from the BS (e.g., configured). The set of first indexesKstart(L) may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of indexes Kstart(L) may be set in the standards. Alternatively, the UE may not receive, from the BS, the first CORESET size CCE^start(L)or the index KstartCL)- The first CORESET size CCE^siart(L)may be set in the standards. The UE may determine the parameter XLbased on the first CORESET size CCEKstart(L).

[0407] In another implementation, the CORESET size CCEKmay comprise a threshold CORESET size CCEKTH.

[0408] The UE may receive, from the BS, a CORESET size CCEKTH. The UE may determine the parameter XLbased on the CORESET size CCEKTH. The CORESET size CCEKTHmay be set in the standards.

[0409] A UE may determine PDCCH candidates to monitor within a CORESET p with a CORESET size NCCE pbased on the hashing function.

[0410] Determining PDCCH candidates may comprise determining locations of PDCCH candidates (i.e. , determining CCE indexes of PDCCH candidates).

[0411] The UE may monitor the PDCCH candidates.

[0412] The UE may receive a PDCCH on an allocated PDCCH candidate amongst the PDCCH candidates.

[0413] It will be understood that since the PDCCH candidates are located in the whole CORESET p with the CORESET size / VCCE pas opposed to a portion of the CORESET p with a reduced CORESET size improved performance may be expected compared to solution 1.

[0414] Third solution

[0415] The hashing function may be based on pseudo-random number Y u , index m^c / , the CORESET size NCCE p, an aggregation level L, a maximum number of PDCCH candidatesws,maxf°r anaggregation level L, a search space s and all carrier indicator values nC{, a carrier indicator value nC{, a modulo function mod and / or an integer i.

[0416] The hashing function may use the CORESET size NCCE pand / or an aggregation level L to set the CORESET p where the PDCCH candidates are located.

[0417] It will be understood that the CORESET size NCCE pmay be expressed as a number of CCEs.

[0418] It will be understood that the location of a PDDCH candidate may be expressed as an index of a CCE.

[0419] The hashing function may use a PDCCH index m^cl, the CORESET size NCCE p, an aggregation level L , and / or or a maximum number of PDCCH candidates M maxforanaggregation level L, a search space s and all carrier indicator values nC[to set the distance between PDCCH candidates other than at least one PDCCH candidate amongst the PDCCH candidates.

[0420] It will be understood that the distance between PDCCH candidates other than at least one PDCCH candidate amongst the PDCCH candidates may be expressed as a number of CCEs. Also, the distance between at least one PDCCH candidate amongst the PDCCH candidates and a PDCCH candidate other than the at least one PDCCH candidate amongst the PDCCH candidates may be expressed as a number of CCEs (e.g., smaller).

[0421] The hashing function may use a parameter Xm Lto set on offset (e.g., shift) for at least one PDCCH candidate amongst the PDCCH candidates. The hashing function may use a parameter Xm Lto set on offset for at least a last PDCCH candidate amongst the PDCCH candidates. The hashing function may use a parameter Xm Lto set on offset for only one PDCCH candidate amongst the PDCCH candidates. The hashing function may use a parameter Xm Lto set on offset for only a last PDCCH candidate amongst the PDCCH candidates.

[0422] The hashing function may be based on: where, for example: for any for a 39827 for pmod3 = 0 , Ap= 39829 for pmod3 = 1 , Ap= 39839 for pmod3 = 2 , and D = 65537; i = 0, -,L - 1;

[0423] NCCEIPis the number of CCES, numbered from O to NCCE p- 1, in CORESET p and, if any, per RB set; nci is

[0424] - the carrier indicator field value, if provided by cif-lnSchedulingCell in CrossCarrierSchedulingConfig for the serving cell on which PDCCH is monitored, except for scheduling of the serving cell from the same serving cell in which case nci = 0;

[0425] - the nCI-Value, if provided, for the set of serving cells MC-DCI-SetofCells;

[0426] - otherwise, including for any CSS, nCI= 0 is the number of PDCCH candidates the UE is configured to monitor for aggregation level L of a search space set s for a serving cell corresponding to ncz; for any for a USS, Afj^ax'sthe maximum over all configured nCIvalues for a CCE aggregation level L of search space set s ; the RNTI value used for nRNTIis the C-RNTI.

[0427] The parameter Xm Lmay be based on a modulo function mod, a CORESET size NCCE pof a CORESET p, an aggregation level L, a maximum number of PDCCH candidates for an aggregation level L , a search space s and a carrier indicator values nCI, a number of consecutive CORESET sizes N^ershootof a peak of UE blocking probability, a PDCCH candidate index size CCEK.

[0428] The parameter Xm Lmay be based on: Xm L= I1 ifmod( 10 otherwise

[0429] In an implementation, the CORESET size CCEKmay comprise the first CORESET sizeCCEKStart(L)associated with the first peak of UE blocking probability.

[0430] The UE may receive, from the BS, the first CORESET size CCE^start(L). The UE may determine the parameter Xm Lbased on the first CORESET size CCEKstart(L). The first CORESET size may be received via RRC signalling or MAC CE. The first CORESET size may beselected amongst a set (e.g., group or range) of first CORESET sizes . The set of first CORESET sizes may be previously received from the

[0431] BS (e.g., configured). The set of first CORESET sizes CCEKstart(L)may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of first CORESET sizes CCE*Ks „tart(L) mayJbe set in the standards.

[0432] Alternatively, the UE may receive, from the BS, the index KKstar The UE may determine the first CORESET size CCE*Ks „tart(L) based on the index KKKs „tart(L) The UE mayJdetermine the first

[0433] CORESET size CCE^K-start(L) based on:

[0434] The UE may determine the parameter Xm Lbased on the first CORESET size CCEKstart(L). The index Kstart(L) may be received via RRC signalling or MAC CE. The index Kstart(L) may be selected amongst a set (e.g., group or range) of indexes Kstart(L). The index KKstart(L)may be dependent on an aggregation level L and / or a number of (scheduled) UEs. The set of indexesKstart(L) may be previously received from the BS (e.g., configured). The set of first indexesKstart(L) may be received via RRC signaling or via a SearchSpace IE (e.g., via an explicit or an implicit field). The set of indexes Kstart(L) may be set in the standards.

[0435] Alternatively, the UE may not receive, from the BS, the first CORESET size CCE^start(L)or the index Kstart(L). The first CORESET size may be set in the standards. The UE may determine the parameter XLbased on the first CORESET size CCE*. In another implementation, the CORESET size CCEKmay comprise a threshold CORESET size CCEKTH.

[0436] The UE may receive, from the BS, a CORESET size CCEKTH. The UE may determine the parameter Xm Lbased on the CORESET size CCEKTH. The CORESET size CCEKTHmay be set in the standards.

[0437] A UE may determine PDCCH candidates to monitor within a CORESET p with a CORESET size / VCCE pbased on the hashing function.

[0438] Determining PDCCH candidates may comprise determining locations of PDCCH candidates (i.e. , determining CCE indexes of PDCCH candidates).

[0439] The UE may monitor the PDCCH candidates.

[0440] The UE may receive a PDCCH on an allocated PDCCH candidate amongst the PDCCH candidates.

[0441] It will be understood that since the PDCCH candidates are located in the whole CORESET p with the CORESET sizeNCCE pas opposed to a portion of the CORESET p with a reduced CORESET size improved performance may be expected compared to solution 1.

[0442] Fig.9a and Fig.9b shows an example of a signaling diagram of a method for determining PDCCH candidates.

[0443] At step 1, a UE may perform a band scan. The UE may read a synchronisation signal block (SSB). The UE may acquire a master information block (MIB).

[0444] At step 2, the UE may read a system information block (SIB). The UE may perform a random access channel (RACH) procedure. The UE may connect to the network.

[0445] At step 3, the UE may acquire a CORESET configuration and / or a search space set configuration. The UE may acquire a CORESET configuration via a ControlResourceSet IE and / or a search space set configuration via a SearchSpace IE. The CORESET configuration may comprise a CORESET size / VCCEjP. Here, the CORESET size VCCE pmay be set to 48 CCEs.

[0446] The search space set configuration may comprise a maximum number of PDCCH candidates an aggregation level L, a search space s and a carrier indicator value nCI. Here, the maximum number of PDCCH candidates an aggregation level one, a search space s and a carrier indicator value nCImay be set to six. Here, the maximum number of PDCCH candidates an aggregation level two, a search space s and a carrier indicator value nCImay be set to five. Here, the maximum number of PDCCH candidates an aggregation level four, a search space s and a carrier indicator value nCImay be set to two. Here, the maximum number of PDCCH candidates M^c / for an aggregation level eight, a search space s and a carrier indicator value nCImay be set to zero. Here, the maximum number of PDCCH candidates an aggregation level sixteen, a search space s and a carrier indicator value nCImay be set to zero.

[0447] At step 4, the UE may receive, from the BS, multiple sets (e.g., groups) of indexes «start( for an aggregation level one, two, four, eight and sixteen and multiple numbers of (scheduled) UEs (i.e., multiple UE scheduling loads). The multiple sets of indexes Kstart(^) may be received via RRC signaling.

[0448] Alternatively, the UE may receive, from the BS, a single set (e.g., group) of indexes Kstart(L) for an aggregation level one, two, four, eight and sixteen and a single number of (scheduled) UEs). The single set of indexes Kstart( ) may be received via RRC signaling.

[0449] Here, the UE may receive, from the BS, a first set (e.g. group A) of indexes Kstart(^) foranaggregation level one, two, four, eight and sixteen and a number of (scheduled) UEs equal to ten (i.e., first UE scheduling load). The UE may receive, from the BS, a second set (e.g., group B) of indexes Kstart -) foranaggregation level one, two, four, eight and sixteen and a number of (scheduled) UEs equal to twenty (i.e., second UE scheduling load).

[0450] It will be understood that the number of (scheduled) UEs associated with a set (e.g., group) of indexes Kstart(£)may not be known by the UE. At step 5, the BS may decide to select (i.e. , activate or enable) a set (e.g., group) of indexes KstartU0 amongst the first set (e.g., group A) of indexes Kstart(X) and the second set (e.g. group B) of indexes KstartCO-

[0451] It will be understood that one set (e.g., group) of indexes Kstart(^)may be selected (i.e., activated or enabled) at a time.

[0452] At step 6, the UE may receive, from the BS, an indication of the set (e.g., group) of indexes KstartU0 selected (i.e., activated or enabled) amongst the first set (e.g., group A) of indexes KstartU0 and the second set (e.g. group B) of indexes KstartC£-)- The indication may be received via RRC signaling or MAC CE.

[0453] Here, the UE may receive, from the BS, an indication of a set (e.g., group B) of indexes K-startC^) ■

[0454] It will be understood that if at step 3 the UE may receive, from the BS, a single set (e.g. group) of indexes Kstart(L), then step 4 and step 5 may be omitted.

[0455] At step 7, the UE may determine PDCCH candidates to monitor within a CORESET p with the control resource set size NCCE pbased on a hashing function. The hashing function may be according to the first solution, the second solution or the third solution.

[0456] Here, for aggregation level one, Kstart(^ = 1) may be equal to two and the first CORSET size CCE^start(L)may be equal to twelve.

[0457] Here, for aggregation level two, KstartU- = 2) may be equal to three and the first CORSET sizeC C EKstart(L)maybe eciual to thirty-

[0458] Here, for aggregation level four, Kstart(^ =4)maY be equal to five and the first CORSET size

[0459] It will be understood that, for aggregation level one, a CORESET size equal to forty-eight CCEs may be associated with a peak of UE blocking probability. It will be understood that, for aggregation level two, a CORESET size equal to forty-eight CCEs may not be associated with a peak of UE blocking probability.

[0460] It will be understood that, for aggregation level four, a CORESET size equal to forty-eight CCEs may be associated with a peak of UE blocking probability.

[0461] This can be verified from the first condition set in the brackets for calculation of the parameter XL(for Solution 1 and 2) or Xm L(for solution 3). This first condition is written below, wherein any CORESET size associated with a peak in UE blocking probability may be identified or checked based on this equation. locking probability may 1X6 / be expected.

[0462] For aggregation level two: mod ( a peak of UE blocking probability may not be expected.

[0463] For aggregation level four: mod I — J = 0 < L = 4 -> a peak of UE blocking probability may be expected.

[0464] The UE may monitor the PDCCH candidates.

[0465] The BS may allocated a PDCCH candidate amongst the PDCCH candidates to transmit a PDDCH.

[0466] The UE may receive the PDCCH on the allocated PDCCH candidate amongst the PDCCH candidates.

[0467] Fig. 10a shows an example of a graph of a UE blocking probability as a function of a CORESET size for an aggregation level one and for a number of (scheduled) UEs equal to thirty calculated for the existing hashing function and the hashing functions according to the first solution, the second solution and the third solution. Fig. 10b shows an example of a graph of a UE blocking probability as a function of a CORESET size for an aggregation level two and for a number of (scheduled) UEs equal to twenty calculated for the existing hashing function and the hashing functions according to the first solution, the second solution and the third solution.

[0468] Fig. 10a and Fig.10b show that the hashing functions according to the first solution, the second solution and the third solution reduces peaks in UE blocking probably.

[0469] Fig. 11a shows an example of a graph of an overall UE blocking probability as a function of a CORESET size for a number of (scheduled) UEs equal to fifteen calculated for the existing hashing function and the hashing functions according to the first solution, the second solution and the third solution.

[0470] Fig. 11b shows an example of a graph of an overall UE blocking probability as a function of a CORESET size for a number of (scheduled) UEs equal to twenty-five calculated for the existing hashing function and the hashing functions according to the first solution, the second solution and the third solution.

[0471] Fig. 11a and Fig.11b show that the hashing functions according to the first solution, the second solution and the third solution reduces peaks in overall UE blocking probably.

[0472] Fig. 12 shows a block diagram of an example of a method for determining PDCCH candidates according to a first solution performed by a UE.

[0473] At step 1200, the UE may determine PDCCH candidates to monitor within a CORESET p with a CORESET size NCCE pbased on a function, wherein the function uses a reduced CORESET size smaller than the CORESET size NCCE pto set a portion of the CORESET p where the PDCCH candidates are located and to set a distance between the PDCCH candidates.

[0474] At step 1202, the UE may monitor the PDCCH candidates.

[0475] Fig. 13 shows a block diagram of an example of a method for determining PDCCH candidates according to a first solution performed by a BS. At step 1300, the BS may determine PDCCH candidates within a CORESET p with a CORESET size JVCCE pbased on a function, wherein the function uses a reduced CORESET size smaller than the CORESET JVCCE pto set a portion of the CORESET p where the PDCCH candidates are located and to set a distance between the PDCCH candidates.

[0476] At step 1302, the BS may allocate a PDCCH candidate amongst the PDCCH candidates to transmit a PDCCH.

[0477] At step 1304, the BS may transmit the PDCCH on the allocated PDCCH candidate.

[0478] Fig. 14 shows a block diagram of an example of a method for determining PDCCH candidates according to a second solution performed by a UE.

[0479] At step 1400, the UE may UE may determine PDCCH candidates to monitor within a CORESET p with a control resource set size NCCE pbased on a function, wherein the function uses a reduced CORESET size smaller than the control resource set size NCCE pto set a distance between the PDCCH candidates.

[0480] At step 1402, the UE may monitor the PDCCH candidates.

[0481] Fig. 15 shows a block diagram of an example of a method for determining PDCCH candidates according to a second solution performed by a BS.

[0482] At step 1500, the BS may determine PDCCH candidates within a CORESET p with a CORESET size NCCE pbased on a function, wherein the function uses a reduced CORESET size smaller than the CORESET size NCCE pto set a distance between the PDCCH candidates.

[0483] At step 1502, the BS may allocate a PDCCH candidate amongst the PDCCH candidates to transmit a PDCCH.

[0484] At step 1504, the BS may transmit the PDCCH on the allocated PDCCH candidate. Fig. 16 shows a block diagram of an example of a method for determining PDCCH candidates according to a third solution performed by a UE.

[0485] At step 1600, the UE may determine PDCCH channel candidates to monitor within a CORESET p based on a function, wherein the function uses a parameter Xm Lto set on offset for at least one PDCCH candidate amongst the PDCCH candidates.

[0486] At step 1602, the UE may monitor the PDCCH candidates.

[0487] Fig. 17 shows a block diagram of an example of a method for determining PDCCH candidates according to a third solution performed by a BS.

[0488] At step 1700, the BS may determine PDCCH candidates within a CORESET p based on a function, wherein the function uses a parameter Xm Lto set on offset for at least one PDCCH candidate amongst the PDCCH candidates.

[0489] At step 1702, the BS may allocate a PDCCH candidate amongst the PDCCH candidates to transmit a PDCCH.

[0490] At step 1704, the BS may transmit the PDCCH on the allocated PDCCH candidate.

[0491] Fig. 18 shows a schematic representation of non-volatile memory media 1800 storing instructions which when executed by a processor allow the processor to perform one or more of the steps of the method of any of Fig. 12 to 17.

[0492] It is noted that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0493] The embodiments may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as nonlimiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0494] The embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any procedures, e.g., as in any of Fig. 12 to Fig. 17, may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

[0495] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi-core processor architecture, as non-limiting examples.

[0496] Alternatively or additionally some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and / or method steps previously described. That circuitry may be provided in the base station and / or in the communications device.

[0497] As used in this application, the term “circuitry” may refer to one or more or all of the following:

[0498] (a) hardware-only circuit options (such as options in only analogue and / or digital circuitry);

[0499] (b) combinations of hardware circuits and software, such as:

[0500] (i) a combination of analogue and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as the communications device or base station to perform the various functions previously described; and

[0501] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0502] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an option of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example integrated device.

[0503] The term “means” as used in the description and in the claims may refer to one or more individual elements configured to perform the corresponding recited functionality or functionalities, or it may refer to several elements that perform such functionality or functionalities. Furthermore, several functionalities recited in the claims may be performed by the same individual means or the same combination of means. For example, performing such functionality or functionalities may be caused in an apparatus by a processor that executes instructions stored in a memory of the apparatus.

[0504] The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined in the appended claims.

Claims

65CLAIMS1. An apparatus comprising: means for determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p, where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and means for monitoring the physical downlink control channel candidates.

2. The apparatus of claim 1 , wherein the function uses at least one of: an aggregation level, L; a physical downlink control channel candidate index,; or a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s, and all carrier indicator values, nc / ; to set the distance between the physical downlink control channel candidates.

3. The apparatus of claim 1 or claim 2, comprising: means for determining the reduced control resource set size based on at least one of the control resource set size, NCCE p, and a value, XL.

4. The apparatus of claim 3, wherein the means for determining the reduced control resource set size based on the control resource set size, NCCE p, and the value, XE, comprises: means for determining the reduced control resource set size by subtracting the value, XL, from the control resource set size, NCCE p.

5. The apparatus of claim 3 and claim 4, wherein the value, XL, is determined based on at least one of: the control resource set size, NCCE p, an aggregation level, L; a maximum number of physical downlink control channel candidates,, for an aggregation level, L, a search space s and a carrier indicator value nCj;66 another control resource set size, CCEK; or a modulo function, mod.

6. The apparatus of claim 5, comprising: means for receiving, from a base station, the other control resource set size, CCEK.

7. The apparatus of claim 5, comprising: means for receiving, from a base station, an index, K .

8. The apparatus of claim 7, comprising: means for determining the other control resource set size, CCEK, based on the index, K .

9. The apparatus of claim 7 or claim 8, wherein the other control resource set size CCEKis a first control resource set size, CCE^start(L), of a first peak of user equipment blocking probability; and wherein the index, K , is an index, Kstart(L)-10. The apparatus of 9, wherein the index, Kstart(L). is dependent on at least one of: an aggregation level, £; or a number of user equipment.

11. The apparatus of claim 7 or claim 8, wherein the other control resource set size, CCEK, is a threshold control resource set size, CCEKn.„.

12. The apparatus of 11 , wherein the threshold control resource set size, CCEKTHis not dependent on at least one of: an aggregation level, L; or a number of user equipment.

13. The apparatus of any of claims 1 to 12, wherein the function uses at least one of: a pseudo-random number, Y„ uP,ns,f67 a physical downlink control channel candidate index,; an aggregation level, L; a maximum number of physical downlink control channel candidates, M^ax, for an aggregation level, L, a search space, s , and all carrier indicator values, nc / ; a carrier indicator value, nc / ; a modulo function, mod; or an integer, i.

14. The apparatus of any of claims 1 to 13, wherein the apparatus is a user equipment.

15. An apparatus comprising: means for determining physical downlink control channel candidates within a control resource set, p , with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and means for allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and means for transmitting the physical downlink control channel on the selected physical downlink control channel candidate.

16. The apparatus of claim 15, wherein the apparatus is a base station.

17. A method comprising: determining physical downlink control channel candidates to monitor within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, NCCE p, to set a portion of the control resource set, p .where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and monitoring the physical downlink control channel candidates.

18. A method comprising: determining physical downlink control channel candidates within a control resource set p with a control resource set size, NCCE p, based on a function, wherein the function uses a reduced control resource set size smaller than the control resource set size, JVCCE p, to set a portion of the control resource set, p , where the physical downlink control channel candidates are located and to set a distance between the physical downlink control channel candidates; and allocating a physical downlink control channel candidate amongst the physical downlink control channel candidates to transmit a physical downlink control channel; and transmitting the physical downlink control channel on the allocated physical downlink control channel candidate.

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