GB2568835A

GB2568835A - Downlink communication in the uplink FDD channel

Info

Publication number: GB2568835A
Application number: GB1901872.0A
Authority: GB
Inventors: Goldhamer Mariana
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-10-21
Filing date: 2013-10-20
Publication date: 2019-05-29
Anticipated expiration: 2033-10-20
Also published as: GB201901872D0; GB2568835B

Abstract

Configuring at least one first base station (or at least one first radio head) for communicating over the air with at least one first user equipment (UE) in a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first frequency range and at least one uplink channel comprising a second set of time resources in a second frequency range, which is disjoint from the first frequency range, enabling communication over the air with at least one first UE to be carried out in the FDD mode by using at least one first time resource. The sets of resources are limited to the time domain only

Description

100021 The present invention relates generally to digitei communication and more specifically to cellular communications.

Background ίίΚ)03| Most of the spectrum used for cellular operation is allocated In a paired way, i.e. two HDD (frequency division duplex) equal-size, frequency channels, one used for downlink t'DL) transmission i'rom a (Base Station) to wireless User Equipments (UEL tmd the other used tor uplink iUL) transmission trorn the UE to the BS, Due to smart phone use, user traffic has become more and mere irsy-nmetrical i.e, most of the traffic is downlink-centric, due to application* such as video streaming, file sharing and internet browsing.

[0004] The average ratio between the DL and UL traffic can reach, according to an Ericsson Mobility Report, November 2012. up to 9:1 (i0% overall). This «asymmetry means, considering that the DL. spectral efficiency is 1.5 times higher than the UL spectral efficiency, that only about 15$b of the uplink channel spectrum is actnally used. Even with a loss aggressive asymmetry factor, such as 4:1, less than 40$i- of the available uplink channel is used. The total avaiiabk- time·frequency rexoumes in the uplink channel spectrum .may thus be 60-85% of the uplink chaimci bandwidth. A number of solutions combining FDD with time-domain duplexing (TDDi have been proposed, For example, US application no. 13/286209 ‘'FDD and FDD carrier aggregation relates to the carrier aggregation of FDD and TDD component carriers, where each carrier occupies its own frequency channels for operation.

[0005] US application no. 13/208213 “Backward compatible LTE system design for asymmetric uplink/downfink spectrum” considers a system which operates with multiple DL spectrum blocks and one up-link spectrum block.

[0006] US patent no. 6859655B2 “TDD FDD Air interface” relates ίο the adaptation of two TDD systems such to operate on a FDD (paired) allocation.

[0007] US patent application 12/777945 “Dual mode radio for frequency division duplexing and time division duplexing communication modes” describes a FDD-TDD multiplexed frame structure.

[0008] US patent no. 7929468, “Method for improving coexistence between adjacent TDD and FDD wireless networks” by the same inventor, refers to FDD and TDD use by equipment operating in separate adjacent frequency channels or adjacent frequency bands. 2 BFOEF SUMMARY [0009] Some embodiments of the present invention that are described hereinbelow provide a cost-effective method for increasing uplink frequency channel use and thus increasing its spectral efficiency.

[0010] There is therefore provided, in accordance with an embodiment of the present invention, a method for communication, which includes communicating over the air with user equipment (UF.) in a frequency domain duplexing (FDD) mode, which defines a downlink channel including a first set of time-frequency resources in a first frequency range arid an uplink channel including a second set of time-frequency resources in a second frequency range, which is disjoint from the first, frequency range. An excess capacity is identified in the uplink channel. At least a portion of the excess capacity is allocated for downlink communication by assigning a subset of the time-frequency resources in the second frequency range to the downlink communication. The method includes communicating over the air with at least one UE by transmitting downlink information using the assigned subset of the time-frequency resources in the second frequency range. [0011] Allocating· the excess capacity may include allocating a sub-range of the second frequency range for the downlink communication and/or allocating first time periods for FDD uplink communication and second time periods for the downlink communication within the second frequency range.

FDD uplink ccmimmudtioii mid second time periods tbs the downimk eomsnuiiii'ariun withm the second fm-quency range tn woe embodiments, a flier base staimn eommuniefae? ovm* fat¹ air with the

UE m the FDD modi,·, and allocating at least a portion of the excess capacity includes assigning the .subset ofthe trnK'daeqacney rcsoim.·^. to a second base station, in a vicimts of she first base «taiion. fa one pftihodiincni, she f’iM base station is a macro base starion and the second base station is a small base .station operating within a coverage .area <>f tfamacro bast station, typically, allocating at least a portion of the escess capacity inefades exchanging cunimimicstioiw between the h ba«e .station and a si and second base >iauor>s oi between eec?

provisioning entity hl order to define <m assignment of toe. time frequency resource?, (O053j fa some in the second frequency range.

embodiments. eon-ninn-earing user the an' includes communieatiiia with the at least one UE in a time domain duplexing (TDD) mode using the assigned jubsci of the rime Itvqucncy resources In a disclosed embodiment, communicating in the TDD mode includes detecting an overlap between a fmsE subframe that is assigned for dm FDD uplink comtitimicalioti with a first base xkidon and a second subframe, dial i« assigned Im

1DD uplink cC’inrnunk'faion with a second base stalion. and mfahkhig uplink transmis.sio within at least one of rhe first and .second subframes.

[IMH4] Additionally or aiternatively. assigning me subset ut the tmic-trequenoy resource* includes selecting respective thae-lrequcncy icsomce blocks for u*c in FDD uplmk communication and fa the FDD esfromtimcarion so as to tmfannze an Imorfereuey between the FDD uplink communication and the Ί1 ID communication. Selcctina the respective time- frequency in the TDD mode so as lesouicc blocks may hicfade scheduling downlink frimsiHi-isfons tii minimize tire fates ic rimer due to uplink acknowk-dgmenfr iransmiited by she m least cue UE at a mt'deieimmed rime delay following the dowfamk transmissions.

KMII5JI fa one enth« .dmicnt, coturauukatrag with the at k-ast one¹ UE includes uoinmufavatiiig with a given UE concureifay in both the FDD mode and by transotfa ng the downlink intonnmiun usnie the assigned subset ofthe time frequency rosowees in ths¹ secund frequency range, lOOl&j Ί here -s afro provided, m accordance with an embodiment of the present inveuthm, communication apparatus, including at k-ad one radio, which is coniigured to cnmrmmicaie over fan air wifa user equipment (UE) in a frequency dmirafa duplexing |FDDi mode, which defines a downlfak channel including a first, set of time·’frequency resources in a first frequency mage and an uplitik rhannel including s 'ecmtd set of tune frequency resources hi a secottd frequency range, which is disloint front the first frequency range A control block is configured to Identify an excess capacity ra the uplink channel and to idk.-tmt-i? a least a portion of the excess capacity for downlink communication by assigning a subset of ibe fime-frcsfaeitcy resources in the second frequency range to the downlink communication. so as to enable the downlink communication to be carried out over the air with at. least one IJE by transmitting downlink information using the assigned subset of the time t'requency resinirces in the second frequency range.

[0017] There ra additionally provided, in accordance with an embodhueut of the present invention. communication apparatus, 'which includes at least one radio, which is configured to cemtmwnicate over the air with user equipment (l Έ) in a time domain duplexing (TDD) mode m a first trequeney range and to row· st uplink communications from the Ϊ.Έ iu a frequency domain duplexing {FDD) mode in a second frequency range which -s disjoint from. the first frequency range. A control block is configured to combine uplink signals· received by the at least one rad-o in the TDD and FDD modes so as to receive aggregated information tmusmirn-d by the 111.1., [0018] St ill another embodiment provides communication apparatus, including at least one radio, which is canfigurt-d to communicate over the ah with at least one base station <

using a frequency channel inimtfiy defined for a frequency domain duplexing i.F'DDi mode, which defines: a downlink channel including a first sot of time-frequency resources in a first frequency range and an uplink channel comprising a second set of time'frequency resources in a .second frequency range, which ra disjoint from the first frequency ra se.

rmge, which m disjoint

Communicating with the base station includes a reception operation using a .subset of second set of ttmo-frequency resources identified as excess capacity A signal procc.-:;· block is tonftgused (0 acquire syuchromzanon with the at least one base station in a t domain duplexing tTDIll mode, in which the at least one base station transmits downlink he n<

information udog the subset of the second set of limefrequcticy resources identified as excess capacity. A control block is configured to read system information transimtted by the at least 0¾ base station m the TDD juudc so as to enable downlink eommumcatiou tn be tamed cm ever the 3tr with the m least one base station in the 'FDD mode.

[01).(9] Additionally, the comsnunlcutmn apparatus can be configured to receive both the downlhtk communication in the fiist frequency range in the FDD -node and downlink infortnation transmitted using the assigned subset of the time-frequency tv second frequency range, rmrees in the [0020 j Fot a better understanding of embodiments of the invention and for shewing how fbe dilfiaenf embodiments may be carried Imo effect, reference will now be made, purely by way oi exampie, to the accompanying drawings in which like numerals siesignate correspond)ng elements [0021] Lt the accompanying d'awmgs:

Pigwe 1 Rep?»' ? uk ,m esimpic <4 I It uplmk phy^oa! channel aliocafioi·

Figure 2 Repst'sems auethee exa up e oi LIE uplink physical channel allnealion. Ftguie J · Represent» a deployment example of a heterogeneous network.

Figure 4 - Repicsents art example of time-resource allocation for two TDD systcraa within an uplink FDD frame.

Figure 5 - Represents another example oi time-resource allocation for two TDD systems within an uplink FDD frame.

Ftguro 6 Reptusenis at- allocation example for one DL-onfy system and two TDD systems ar: uplink FDD frame.

- Represents the GF. internal architecture.

Represents an example of Ϊ..ΊΈ uplink multiplexed physical channels kt conjunction with the DL TDD frame structure;

Figos v 9 - Represents a modified TDD base station:

Figure iii - Represents a deployment example or a heterogeneous FDD and TDD network; Figure 11 - Represents an example of tinie-resource allocation in a downlink fra-ne of an FDD btoe station for avoiding. FDD operation in specific «nbfr.'unsas:

Figure within

Hiusmtics muhiplexed uplink subframes with different Time Advance Groups':

and

i.3 Repse.-x-ms rm ahocatlo.?; example for two base stations hwe

1’ frequency dnrnain description u-:tw a and in piyticubr m hould not he considered as a limitation the principles embodied in [0022J For the sake m simplicity and elariiy, the following terminology that will be familiar to those skilled in wireless aeeworis Lil; ami WiMAX technologies. This terminology s tor the general applicability of she invention, ns the, extension r rite description to other types of networks wdl be apparent to tho«c skilled in the art and m consideted to he within the scope of the pte.mt invention.

[0(123] The term User Equipment” indicates device either connecied over the air to a Base Station (BS) -vr able to cotmuunicate with ca'w-thor device O'·' the same type, ihe Ul. may be m.ed by a person or involved m machine-type applieimoux, such as sensors, IV surveillance, etc.

[0024] Ί he term 'incumbent BS” is used to indicate a cell deployed m FDD mode which, in embodiment;-; of this wvemion. makes room for die ope-atkm of other new ctlU on its uplink freaptcncy chai melt st, [0025] Akhough the embodiments described below refer, for simplicity, only to cemrahzed m point-m-multipoint vmvtes-s systems. the principle^ of the invention may also be appl’ed to mesh e-r mmftpoini to multipoint wireless systems.

Sente embodiments ol the ptcrent mvenram consider the firt that a LE ‘J'sei Equipment) that is compatible with LI I: Release S could ifanMim wtthm all available suhnarnes of the UL fsequrncy channel m aide; to pmvsdc A(‘K/,\AGK tcedback on ^she PUCCI I (Physical Iplm.k Cnnttot Chaimeb relined m the ti^epiion of th^f DL tm man it-cd data. .ACK/XACK tiansmw nou m LPL r drsciihed 'In example m ?GPt* IS 36 .'13 [10)27] Embodiments of the present u-vtntion are designed to provide hackwatd compatibility with UEs compatible with I..TE Ret. 8. but the principles ot the&e embodiments arc applicable to all FDD wireless sys-oms. using technologies such as HSPA, WIMAX HEEL 802.163. microwave P-P (potnt-to-pomti and P-MP (point to multipoint} and evolution⁴· of these technoh-gies, [0020]

As wdl known to those skilled in the art, the LTD F’DD UL f'mme is composed of ten subframes, on which me mapped the physical chimne-ls, The PUCCI f (Physical Uplink Control Channel) and the corrvs-.pomltng DM-RS (demodulation refemnee signals), considered herein as part of the PUCCH. ate mapped on the equivalent Physical Resource Blocks l iSOkUr/PRB) ar tits chmwd edge, Che PUCCH contains lite UCI {Uplink Comrol Information) and it' transmission comprises the ACK/N'ACK, scheduling request, ^nu periodic CQl feedback. Uplink data is transmitted within the RUSCH tPhysimd Uplmk Shared Channel), expanding over a continuous frequency allocation equivakm to an integer smmber of PRBs, BUSCH may also mclttde uplink c-mdiol information,

KKl2$| Figure 1 slums an example of the usage of an uphnk FDD allocation by an 1/-1system. Figure I and the Ib-lc-wiug Figures show the PUCCH and PUSCH (Physical Uplink

Shared Channel} as rbne-freqneney resource ailocutioijs as seen by an eNB (LTE base station}. The PUCCH (101 and 102) i> snapped to the tesource blocks at the channel edge, while in this example the allocation 103 of the PUSCH expands across the frequency domain, being present in all the available time resources.

[00301 For example, if we. consider a 10ΜΙ Iz frequency channel composed of 50 pRBs, the extreme two PRBs on each side could be reserved tor PUCCH. whtlc 1/3 of the remaining ones, i.e.· C PRBs could he reserved for PDSCH, Such an allocation is suitable fo; an average traffic asymmetry of 1 >4 (UL:()L).

[0031] The rest of the 31 PRBs across she channel bandwidth are in fact a “free timefrequency resource”. Reserving the PUSCH near one of the PUCCH allocations, as shown in the figure, makes continuous room for the other usage of the available time-frequency resources, such as TDD.

[0032] It should be noted that a specific FDD LTE LIE will send the PUCCI I with UCI containing ACK/NACK in the subframe. i---4 relative to the DL subframe ?. in which the eNB (base station) has sent DL data to the specific UE. UCI, includmg ACK/NACK, can also be sent on the PUSCH. A UE compatible with LTE Release 8 and Release 9 cannot send the PUSCH and the PUCCH io the same subframe.

[0033] A good scheduling practice is the allocation of the PUSCH resources towards the center of the band, where the high power UE transmissions should be scheduled in order to reduce the OOB (out of band) emissions into the adjacent channels.

[0034] Figure 2 depicts an uplink frame where the user traffic (PUSCH-203) is scheduled in the frequency and time domains in a way that makes resources available for EDD, The PUCCH. howevet - 101 and 102 has still to be reserved at the channel edge.

[0035] The FDD UL frequency chromel is only partially used, as the tJL liaffte is taking place only in the latest subframes in the frame (203). Given rhe operation of half·· duplex terminals, which cannot receive and transmit at the same time, and also due to the importance of the DI., subframes 0 and 5 carrying synchronization and control channels (Physical Broadcast Channel carrying the Master Infimnation Block (MIB), it is preferable to allocate the PUSCH in the last subframes of the frame.

[0036] However, due to the fact that legacy UEs use the PUCCH tor transmitting control information, including ACK/NACK feedback for the DL infotmatifm transmitted four subframes previously, it is important io implement this invention so as to avoid interference with these PRBs.

[0837] Note thin for use of the free fmte-frequency resource as shown in Figure 2 by wireless entities not belonging to the main FDD cell, them is a need for time synchronization between such entities and the frames of the incumbent FDD base station. [003K] Of course the allocation of the. used resource block could be more flexible, for example by twmg non-contiguoux subframes os by using partial channel occupancy in contiguous or non-contiguou* subframes.

[0039] Embodiments relating to usage of the available time-frequency rexourees within the uplink channel are described further hereisibclow,

FDD-TDD operation in the saaw FDD unlink channel [0040] The first application at hand Is TDD operation within the available tune frequency resources of one o; more FDD systems. The iitterference created by TDD systems io FDD systems and vice versa is problematic and typically requires at least a reduction of the transmission powers and assessment of the out-of-band emissions. The reduced power transmission is suitable fre small cells, such as pieo-cells or femto-cells, wherein both base station (eNB) operation and DE operation are at lower powers due to the reduced cel! size.

KKM1J Let's consider the deployment scenario in Figure 3: in the coverage area of a macro BS 301 (MeNBI) are deployed small base stations SeNBl - 3lD and SeNB2 - 303. A user device 305 (DEI) communicate* with MeNBL while UE2-304 comjnumcates with the SeNBl-303, Each MeNB operates on three Jirectioaal sectors. Each sector may use the entire bandwidth of the concatenated three sectors (cither Reuse i or Carrier Aggregation) or may apply a policy of having each sector use different frequency channels, When the entire spectrum is used by each sector, based on FFR (Functional Frequency Reuse), IC1C ilnrer-Cell Interference Coordination) or elCIC (Evolved Inter Cel? Interference Coordination), interference rnhigaiion procedures may still be applied to avoid high transmission powers within the same frequency resource by adjacent sectors teNB't tn the same 8S or by interfering eNBs. The effect of this policy will be that the scheduling of the ou-upied time-freriuency resources by the Interfering transmitter* will be different between different eNBs.

[0042] In one embodiment of this invention, the up-link free time-frequency resource is used by the small eNBs, An example of such usage, derived from Figtree 1, re show;· in Figure 4. The immmbent FDD system has the reserved frequency allot'atioa.-.· It)I and 102. for PUCCfl and HD for the PUSCfl. TDD base, .station SeNBl uses the frequency resources within the channel indicated by 404.. and SeNB2 uses fhe frequency resources within the channel indicated hy 405. Th? TDD downlink subframes ere these noted 'T)'\ rhe TDD uplink subframes: are noted IT'’ and the TDD special subframe is noted S”'. PUCCH allocations for UEs served by ScNBI are indicated by 406 and 407, while PUCCH ahocatlrms for UEs served by ScNBl are indicated by 40S and 409, [0043] Figure 5 presents an allocation for the 'TDD systems derived from the free timefrequency resource presented in Figure L but with the PUSCH of the FDD system placed In the center of the bund. The mc-unbcnt FDD system has the ieserwd frequency aHocationv 101 and 102 for PUCUH and 504 for PUSCH. Each ‘FDD system uses rite frequency reso'dtees indicated by 503 and respectively 505.

[0044] Btgure 6 presents an allocation derived from Figure 2 for erne DL-only system606 and two TDD systems, occupying the available frequency rcsomcex 604 and f>05 for a number of subframes not occupied by the incumbent FDD PUSCH allocution 203.

[0045] An example of the design of the FRP ahocml-ma for each of the FDD and TDD systems in Figure 4 is shown tn Table I:

Table I

	k'k’NB FDD	SeNBI TDD	SeNB2 TDD
Chamim IDVfMHD	10	3	3
Resource blocks	50	.15	1.5
RBs for PUCCI 1	6	i	'1 '
RED tor PUSCH	11	13	13
Sparc PRBs to be used for guard-bands	^::3........
PRPfr Slots for UL	170	45	45
PRB Mots for DL (TDD “FT subframe was considered as DL'l	500	. 1.05 '	105

h^band F1W-TDD tnterfertmet· etmrdimtiioQ «V [0046] Strict cooidination of the scheduling of traiisniit and receive operations in the

UL frequency hand can contribute to miligimon of interference,

p.M)47] Such coordination is based on idenrtticimon of the interfering FDD UEs m-o the

TDD s'eccsve operation and the schciiuhtig o! the respeefiv·' h'ansmisMons and-for recenttons so as to avoid interference.

[0048] The scheduling may involve usittg different subframes for transmission and reception.

[(1040] Another interfeieiteo ruhiga-ieit technique, mcludmg for FDD Ί DD PRR terse position in each of the FDD and 'FDD ceils [0050]

In the ease of interference created by UL transmission of a LIE served by the

FDD cNB to a seeo-ui HE receiving the DL. signal from a TDD base stolen, the relevant parameter is the distance between the interfering DE and the interfered UK. The distance car; be obtained by assessing dse UF. position using Eeehniques as GPS, Galileo. Raida or sim-lsr satellite·based positioning, or by radio-based position assessment, as speeifie.il in .standards and using positioning reference signals.

[665H in the case of interference cn'ated 1w a TDD base station. trai;sirti it ice on the

OL FDD frequency channel, to a FDD base station recchmg the Signal from a served 1 Έ.

as long as the quality of the received siguul from lite seised LL at the FDD base tail·· -u aHo^tt suitable reception of the LT. signals. it is possible to reuse the PRB? in both base station ](HIS2| In the case of iiiicrieience esuated oy a UL served by the FDD base •uatiou to the TDD base station n'-ceiving .i signal from a second DE, again n is possible to identify the he OF transmissions rath?.:' than the UL transmissions. For example lor at elding iniertcivtiec created by the uplink operation of a UF on PUCCH. the scheduling of the downlink trausmEsrionv. causing UL trausmissfort oi'lhar DE four subframes later, should be modified, [0054] Such modified DI. scheduling may involve the scheduling of ths' DL transmissions in another subframe m the iuserthm of AB.S (muted) DL. subframes; there is no .need for ACK, because nv DL dura was iranufotted. so that no UE 'will send

ACK/NACK font subframes laser or when established by the standards m c;w of TDD.

[0055] Another possibility B mrerfcrence alignment or CS/CB (Coordinated Schedttlmg/Beamfnrtnmg): Data is available only at the serving ceil (data transmission from that point}, but user scheduibig/betiEufonmng decisions are made with coordination among cells corresponding to the CoMP (coordinated multi-point) cooperating set, [0056] .It the TDD and the FDD small ceils arc part c-f a UL· CoMP set. implementing joint recepti-on and/or coordinated scheduling, for example by using Remote Radio Heads controlled by the macro eNB as center of ths small cell, some overlap may be possible between the PRBs used by the FDD macro cell and the FDD small cells for UL tr.iiix.iuissL.it'i, [0057] In the section below we will first analyze, with respect to interference created to an adjacent channel, the possibility of operation of two TDD additional cells within the fice DL FDD channel t esource.

Instead of a full coexistence study, considering the path loss between Ute imerfercr and the victim, we will just analyze the difference between the out-of band iOOB) emissions of a regular FDD UE and the OOB emissions of d-e. TDD BSs and TDD UEs. By this analysis it will be possible io assess whether the emissions of rhe TDD systems into the FDD system are at the same level with the emissions of UEs deployed on an adjacent FDD channel.

[9059J The emissions of the FDD system into the TDD system are considered as ITJO Ti emissions, which cannut be higher than the UE emissions operating over the entire FDD band, or PU SCH emissions, which cannot be higher than the iransimisxiotts of an UE within a simihir transmission bandwidth, [1X16(1] We will assess the imra-system interference. based on the masks Im 3MHz. systems. In foct, our two TDD systems and the PUSCH of the FDD system behave as three systems with a 3MHz channel bandwidth. If we divide the 3MHz· by the PRB width (180kHz). we obtain 16.6 RBs while the occupied BW es only J5PRBs. This means that at each edge of the channel them is an unused frequency of O.fcPRBs, while in our design lhe spare frequency Is a foil PRB.

[OOM] Ba.xcd on the UE masks in 3GPP T$ 36 UH mid 3GPP T$ 36,104. I 'able 2 presents the mwamlied power density at the edge of the channel,

U

2.U5MHz

ΓΰόΜΗζ

Table 2 intra -channel emissions i Conclusion .i

IJEJOMik .	....................ΰΕ-ΪΜΐΰ...................	TDD Ϊ ,ocJ area j
		BS. iMHz j
FDD ΡΗΟίΊΙ only	(TDD UP, FDD PllSCH
	on 3MHz)
(used as reference)
		..
~18dBin/3GkHz		-2?dBjn/iobkHz.~
		: AOdBrnOOkHz \|
		......]
• lOdBm/.MHz	-1 OdBm/MHz	-lOdBm/MHz Ϊ
-iOdBrn/MHz	•i(klBm/MHz	•25dBm/MHz
-IJdBm/MHz	23dBm/\ffiz	-25dBm/MHz
ί^?ί5ϊ> imerte-vHi-e ~	O0B transmissions	SeNB interference [
reference	higher only for	equal or
	0-1 MHz OOB offset	significantly lower ·
		than the FDD UE reference ................_........ .... . J

iwm The conclusion of 'fable 2is that the small power eNB will create interference similar or sianifieaiitly lower relative to that created by a regular UE.

[0063] From. Table· 2 it can be concluded that the co-channel problematic situations arc:

1. OOB emissions created by the TDD UE to the PUSCfl of the- FDD channel.

2, OOB emissions cieated by the PUCCH to the adjacent TDD system..

[0064] Possible solutions to tbe*e cases may be:

[006-5] Λ. Higher guard bands between flic TDD UL transmlssieiis and she PUSCH, eventually only hi the suhlmmcs in which them are high power UL transmissions, [0066] B. Placement of the hlsb power TDD trimsrr.issio’w in the center of the occupied hand.

[0067] C. Reducing the activity and/or the power over the PUCCH of the FDD system. The power reduction can be achieved by appropriate scheduling of the Di., transmissions towards the remote UEs. s-uch that the ACK/NACK will be transmitted when PUSCH is active and not within PUCCii. or by mapping frequency hopping.

[OtkbS] Such scheduling takes into consideration

ACK/NACK with highe?' power. in ?esponse to ibe PRE', used for PUCCH without that remote UEs will transmit toe

UL ti'afii-njissions that occurred four ubframes earlier. So at least for one lil. tDf 5 suofmmc overlapping the FDD DI.. and another UL FDD subframe ovej'Iapping the TDD UL. the FDD cNB scheduling of DL transmissions taking place four subframes io advance uhotod target lower-power communication with near-placed UEs. This approach enables the FDD 8$ to control Ute tra??s?mtted power by the srspectivc UE to he Mgmftaaiitly lower ?md thus will reduce the mtedercuci.' of the FDD PUCCH in the TDD subframes. Such low-powv?' mansmisMon Is similar to the deduution ot the power transmission in the ABS (Almost Bla??k Subframes), where the transmitted power can he also reduced to zero.

Interference otiUide the UL FDD elmmwl [0069] Adjacenochannel inkx’frrenee in the FDD uplink '.peefrutn is created by UF

UL transmissions. Some embodiments of -he present mvemmn provide lor DL iransmisMon by a 4 DO base .station or art additional DL-ouiy mms?mner, Operators using the adjacent FDD chancel could experience mtor-me-tcc creased by such downlink transmissiom in

Ul FDD ehmmri at a level similar to that, caused bv the interference created bv v· V transmissions [0070] Ilie adjacent channel mterference is also reilecwd by the LIE ACER (Adjacent Channel Leakage Ratio?, with values of 30dB fm reguia?' UE and 4xlB tot tUB (see 3GPF

TS KU and 3GPPTS 104).

[0071] The I?dB diffesence in ACER cun acuontmudaie the 1 DD lovt power eNB higher auiennn «ait? and its hisihor activity factor, such that lite ::ttm'ferei?oe experienced due to DL.

Sj- v z .1 transmissions will he ar the same level as that experienced l'r?-m Ut t-ausmi^iuns.

UL-mt [0072] The UL-tntensive appfieaiious that could be acce-mmodated within the .free UL spectrum arm for esum?pk^k, video surveiiliptce ;md sensor iteiworks. having a pronounced uplink activity factor. For such «pplicutEOUs TDD small cells can be used. (LTE frame type 2, conftgitruiion 0. has four DL 'mbfra.mes atuJ six UL subframes, because the S-auhirmue is ,d mostly a DE subfratne.) [()0731 The FDD small cell will occupy for its uplink operation the Dec part of tbc Lt channel (figure I or figure 2 or thvir combination). Additional considerations are:

A..

B.

Rs DL channel should be placed «neb that the duplex spacing is j

IL du-unel size may be lower than the incumbent Fl)l.> channel·.

For avoiding inter-cell interference. the right ICIC (inter-cell interference coordiuuiio:':) or eICK’ (evolved ICIC, usina ABS ...... almost-blank subframes) should be nnplemcnwd.

Additim^l DL traffic [0074] With the carrier-aggregnjjon (CA) coneep? it is possible to use the free UL spectrum as additional DL frequency resources. When the additional 1.)1.. cell is collocated wkh the? main cell, the DL transrraxsiiws of the secondary cell should be squirmed tn the time domain from the uplink transmissions of the primary incumbent FDD cell, for avoiding in-device coexistence problems, In other words, it is possible lo use an arrangement similar to that in figure 2, with -he additional restriction that for a specific UE there are no transmissions on PUCCI J during the DL transniijMOm. of the secondary cell, Such a condition can be achieved with accumulated ACK/N^TACKs scheduled only in the non - interfering, subframes or by ustng subframes' in which no ACK/NACK is expected. [0075] The downlink-onlv traffic can be unicast or broadcast..

[007N Figure 6 represents an additional DL channel 606, which uses the UL free spsctnm- together with twoTDD systems.

[0C77] Additional interference instigation factors can he one or more of tht- following;

[0078] A Larger guard-bands between PUCCH and the DL transmissions, such that the interference will he· caused by the second adjacent chatmcl [0079] B. Usage, for the additional DL transmission. of an antenna well isolated from the FDD primary transmisnon. For example, if the primary transmission is in Sector I of a tri-sec-tor BS, the additional DL lor Sector 2 can be mapped, within the frequency channel tnmsmitred by Sector I and vice-versa. Based on the OOR trausraission limits for macro eNBs, a -65dB antenna isolation reduces the interference of the additional DL into the UL reception to »94dBm.

[0080] C. Interference cancellation at the BS, by subtracting ihe interference created hy the transmitted signal, known at the RS. from the received signal.

[GOBI | D. Scheduling rhe DL transmissions in the main FDD cell and controllmg the POUCH power >o that the PUCCH will be received during the secondary DL subframes at relatively high power.

......... iSi . ·.♦:*. .<· [0083] i'here ate nmk-plc reasons for having n fsex'-bie- xpechmm allocation policy for ail the interacting systems: rhe FDD system, one or more TDD systems. s.nd one or more

2?

additional DI. resource Such rea-mm; may include variations o! traffic. radio channel conditions, interferences, etc.

[0083] In LTE, -he channel width of tire syssem is transmitted or· the dc.wnliuk as part of the M1B tMasmr Information Block) information. However, not all the DL resource» have to be used, making possible a numhci of means for mterfosence rakigafom, such as the wmsmissson of PRBs with no data or reduced power data, MBSFN (Multi media Broadcast Single Frequency Network) subframe» with no data, ABS i,Almost Blunk Subframe» i without data, and ARS subframes with low-powei’data.

These variations allow ths¹ actual ismcMraquency resources occupied by the DL transmissions of the ceils and the power of these transmissions (o vary in time, contributing m simitar variations in the IQ„ direction, [0085] Interference measurement combined with messages between the eNBs sharing the uplhik chamiel may conlribute lo the coordimstion of spectrum use and tran-imitjed powers In different subframe:- and resource blocks of the uplirsk frame, [00801 The size of the Id. free titne frequency resource tuny vary in rime al»o depending on the variable Ι.Π.. traffic amount, ch-inuel conditions, etc.

[0(187] Ako in uplink it is possible lo modulate tin a similar mode with the Dim the occupied time-frequency resource. by making available time-frequency resources of the TDD? and/or of the downlink only and/or of the uplink-intensive transmissions for the operation of ilie incumbent FDD DE data trati.sfuissiuns in certain .subframes.

LTyarehifocfure for game IT, channel FDD-TDD (jamer Aggrcgutio nnd Dual ( fonrmetivity

188] Sonic embc-dnnenfr oi the present mvention provide t’arrior Aggregation tCA) between the IDD earner, operating on the FDD DI channel and FDD UL channel, ansi the

KMI89] A L’l: implementing such operation has a rest advantage over using CA for channel freqtnmck¹. in difl’ercstt radio band», such as 2.6GHz. and 3.5(>Hz. as both FDD and TDD uplink re. the same band can he supported with no need for a separate radio filmt m a [009<H When 'FDD operallou is- added t j rise segulas FDD operation on the uplink FDD channel tor the r-anie HE, an additional receiver radio chain ss needed withm the. LIE. as in FDD· TDD carrier aggregation or Deal Connectivity.

HHBH] Figure 7 draws the rev Itrag LI· Cfdntceuise i'-,c ventral mm eontn? including the iifnctrao.s iclattx te the Act Plane e 51 Centod Rhine as dew; shea in 3DFF TS 36,300 and radio acrixice-, .s locates: within a centr,,. piows.- tg umt /CL ehteh may abo perform other high-layei isra severs mc.udjng u; -ning apphcmioii» [0092] The user interfaces, sue o the display. sac ikes, and r .otophone, .us' b : uted ni a User interface block 76 i, [0093] A memory block 70S, rainracmig R\M and non vohnlie memory (FI ASH m ROM) is used by the central processing unit 702 and depensling -m the actual IE implementation, may be used also by the uwr interlaces ⁷t;i

10994] Digital signal processing performed by a signal pmecssmy blouL ⁷03 and can give services to the radios using FDD fr-r commumeatiott like radios 706 and 767. using licensed bands, which are highly relevant For this invention, and also to other ladios 7d9. such as WiFi and Bluetooth, operating generally ra license exempt bands, A eornnmu antenna 705 can be used for receive tRX: and timisum (TX), while using diplexeis o: 'Witches to connect it. If the receive and transmit radio frequencies are Dr front each mhos howwet, different antetmas may be used.

[0095] The presented radio architecture, excepting the RA chain 706. is similar to conventional UEs, The additional receive radio 706 may take advantage of the existing radio frequency synthest<er.x in radio 707, so as not to duplicate the entire radio chain, [0096] Embodiments of this invention arc well suited for dual comu’clsvity, also kiam n as nmlti’strenm aggregn-icu. A possible embodiment is the use of the incumbent FDD base station as Master eblB and ibe TDD base station. operating within the available channel resources. Seem alary rNB

[0097] hi the following section w< souudei’ that ntc Operatoi uses a frequency band either ta FDD os TDD mode, deploying a ditteront base station for each treqtieno band. The base station, can I?-, eolfocared or <..m use Remote· Radio Heads (Scenarios 1..4 hi Annes J of 3GPF TS 36 3^!“) V11 7 0 (2011-09)¹ or can be non-collocaied, as in the Surah (Til Seenmios In 3GPP tl< 36,734.

[(0)90] In iitcse scenarios. I DD and FDD operations take place in a .specific hcqurney band fot each duplex and the UL traustnUsions are .‘-ent using djlTenml rad-o channels ter each FDD or TDD band, or by fas· switching of the UE transmitter between these bands.

[0099] For example, TDD operation -nay take place tn the 3.5GHz band while the FDD operation takes place in the 2,5GFb, hand, wherein 2.5-2.57Gtiz is used for uplink.

[00100] I'htwc embodiments are compatible with the following carrier aggregation concepts provided by KiPF i'S 36-300 Release 11; “In Carrier Aggregation (CA), two or more Component Carriers sCCx) are aggregated in order io support wider transniission bandwidths up to 100MHz. A UE may s-nraltaneonsly receive or transmit on one or multiple CCx depending on Its capabilities:

A HE with .single timing advance capability id? CA can simultaneously receive and/or transmit on multiple CCL corresponding to multiple serving cells sharing the sain;.· timing advance (multiple serving ceils grouped tn one TAG);

A UE whh multiple timing advance capability for GA ca-? sirnuitaneonsly receive and/or trammii mt nonuple (XL correspondhtg to multiple serving c· tinting advances (multiple serving cells grouped in multiple TAOs). E-UTR.AN ensures that each '1 AG cot-tains at least one serving cell;

A non-Cfi capable XIE can receive on a single CG and transmit on a single G<“ eocresponding to one sera big cell only (mm serving cell in one TAG).

[OOllB | C3 is supported for both contiguous and non-coniiguous CCs ra ith each CC hunted to a maximum of 110 Resource Blocks in the frequency domain using the Rel-S/9 mtmer-Jot’v/’

Is with differed radii* [(0)1(12] rhe phrase Xmrahaucouf-.ly n.-cewe or irtu-'-mif does not necr»’iarHy require the «sage of the sasne subframe to?'GA operation,

100103] In the ca,e of FDD TDD GA iCanier Aggregation< or Dual Connectivity <or cemmunieauoti systems enjoying mashnun! rehedulmg fjesibihty, two R.x (recer.e chains and two transmit i'l'x;· radio chains uro needed lor each UE (user equipment) implementation. The reason w that in (Ά anti Dual Connectivity. FDD and TDD operations take place in different radio bauds.

[00104] Given that a legacy UE typically supports only one Tx radio chain, a suitable method Is needed Co? multiplexing transmissions towards two eNBs, cads eNB operating in its own frequency channel -and possibly using a d i ft orent duplex mode.

:00105] For cbnireatiom in FDD-TDD Cl\ the operational frequency ehamH-D for FDD and TDD belong to different radio bands, while the 1Έ communicates with collocated FDD or TDD cells or with non-coilocated FDD or TDD cells created by RRH {Remote Radio Heads) linked to the same base station, in Dual Connectivity there are at least two ba<o stations involved, and the MeNB (Master cN.B> or the SeNB (Secondary cNB) may use different radio channels, belonging to the same or io different radio bands.

[001061 A possible solution for using only one Tx chain in uplink for each UE is fast switching of the radio channels, but this switching may result in long settling times and high spurious signals. Embodiments of the present invention provide a cost effective method for overcoming these [mutations.. by exploiting the downlink-centric traffic asymmetry and the resulting low occupancy of the uphnk channel.

[00107] In the section below we describe a solution for avoiding the switching ol the UE uplink radio transmitter. This solution takes into account the free time-frequency resources on the uplink FDD channel.

[00108] The solution makes nse of multiplexing of the transmissions to ihe different base stations while exploiting the free fwc-frequency resources of the FDD uplink· channel.

[08109] Figure 3 presents a TDD type 2 frame structure based on Configuration I iu TS36.211 Release 11, operating on the frequency channel Γ3. The DL :ransmission of the FDD base station mires place on frequency channel 12. Multiplexed operation in the time domain of FDD and TDD uplink chmmels takes place on the FDD uplink frequency fl.

[00.110] The main physical channels shown in Figure 8 are its follows:

- Pl JSC - 803 (physical uplink shared channel - refereed to ax PIJSCH in LTF. standards);

- I’UCCH (physical uplink control channel) for FDD dOI and 102);

- PIJCCH (811 and 8)3) for TDD;

-RUSCH t812), indicated as PDSC for TOD,

1001 u I Ihe time-frequency jcsouwa are allocated such <> avoid contentions at receiver, i.e. the allocations should be orthogonal.

[00112] Tire exact usage of the subframes car; be dynamically esiabhshed based ou the uplink traffic characteristics in each base station: however, a sampler provisioning approach can be also used.

[00.1.13] Based on LTH SC-TDMA technology, a UE with a single RF Tx cannot transmit two different signals at tire same time. Thus, Figure 8 shows the aggregated channel usage as seen by the base station where the Irfresfurxaious arrive from multiple UEs.

IS [00 Η 4] in order to achieve the multiplexing that is illustrated here, the TDD base station should be able to receive signals on the radio channel allocated for the FDD uplink transmission. When the FDD and TDD base stations are collocated, this condition can be achieved eaul>\ at no additional cost; when the FDD base station is a macro hose, station, and the TDD base station is a small cell, there will be a cost incscase in foe TDD base station. as an additional Rx RP chmmcl h added. This channel may include· diversity or ΜΙΜΟ support, such that in practice it may use more than one radio chain.

[001B] The· modified TDD Base Station radio architecture is shown in Figure 9.

I·': this figure the base station modules include a Network interface · 901, providing the data connection and a Base Station Control Block 902. mdnding the LTE Control Plane and the LTE User Plane, which also transfers user data between lhe Network interface - 001 and a Signal Processing unit - 903. which in turn receives and transmits the baseband rdgnals to the radios, in addition to a regular TDD radio 906 using an antenna 904. (hem is an FDD receive channel 907, which may use the TDD antenna 904 or a separate antenna 905, if the FDD antenna does nor cover the frerptency band of the UP· FDD channel.

[00116] Oofo TDD and the FDD base stations -ccUve the multiplexed signals of the physical channels for FDD and TDD operation and select the relevant physical channels for processing.

[001.17] A Memory block 908, containing RAM and non-volatile memory (FLASH or ROM), is used by the eNB Control iJuit 902 and depending on foe actual eNB implementation, may be used also by the Network Interface 901.

DuaLCotmeelivUy [0011S] In the case of dual connectivity. an UE can receive signal from two different base stations.

[00119] A deployment example is shown in Figure hl. 'The FDD base station 301 is a macro base sin-ion having three .sectors. Within the coverage area of a sector 1902 is deployed a small TDD base station 303. UE 304 is connected only to ‘he TDD base station 303, while the [JE 305 is connected to both base stations and is able io communicate with both In the same frame, [00120] The multiplexing approach explained for CA is also suitable for Dual Connectivity. such that everything related to the multiplexing approach explained in lhe context of CA should be understood ns also valid for dual connectivity.

D

Ayqidmg Fl)l> PUCCH tn, TDD ,sid>h';jimes [(MH 211 Some relaxation ofthe coordluattoo of the PRBs {Phy.siciil Resource Block) allocated for FDD and 'FDD operation in the uplink FDD channel can be obtained with suitable allocation of ABS (iilmoat blank .«ubframesi or even PRB muting.

The ABS allocation should be such that there will he no need £>r i'DD IJARQ (Hybrid Automatic Repeat RequcaD or simply ACK7NACK in those subframe* in which TDD operation takes place.

[00522] An example oi ΛΒ8 ailocation. tmhalue fm Type .;. LTD frame structure ‘'configuration I,” is shown in Figure 11.

[001.33] As it can be observed, an FDD DL- ABS (or a muted or MBSFN) subframe 1103 is placed four subframes in advance relative to a TDD UL subframe 1102. Given the frame, repetition in time, an F'DD DL ABS (or it muted or MBSFN1 subframe HOT is also lour subframes in advance relative to a TDD UL subframe 110L [00124] If in subframes 1.103 and 1104 is transmitted no data requiring ACK/NACK. there is no ultimate need to schedule ihe FDD PUCCH within the siibfranws 1101 and 1102.

[00125] Due to the resulting, lack of contention between FDD P1JCCH and the TDD UL subframe, the TDD Ul subframe can occupy all the PRB resources of the subframe.

Time advance [00126] In some deployment cases, for example mm-collocated TDD trad FDD base stations or large di’ference between FDD and TDD frequency bands, the FDD and TDD transmissions may use different values of UL time advance. As .·ι consequence. the VE could operate with time advances belonging to different Time Advance Groups (TAG*J. and there may be so some overlapping between the. 111. subframes belonging to different TAGs.

[00127] A solution to this problem is shown in Figure 1.2.

[00128] In the pictured scenario, the FDD frequency has a higher delay as compared with the TDD frequency, such thui a time advance TA - 1'203 for FDD is higher than a TA1205 for TDD. This difference creates a potential overlapping between the UL. subframes 1201 and 1202. which can be resolved if no data i* transmitted in. the UP. FDD subframe 1202. The· suruc situation occurs in an FDD subframe 1207, and the same sohitm·; can be applied.

[08120] It th«‘ overlapping duration is low enough ttot to affect the receive operation at the base station, no conective actio;· is needed.

[00130] If the overlapping dmatiou is too high, the UE transmissions that car, create reception problems should be avoided [00131] hi order to avoid undtsirahk* trammiRsions.. includin’? PUCCU. ararc flexible transmission of the mlormati·-n elements snamdcct in the UCIi. desnabhx ’ e. totuMmsCrm ot the UCl information dement'-' t IF) should hr- flexible sod programmable, Instead <n f the ffstrict; nt which the UCI IF« could be transmitted require a aew provisioning or else Fetter cooidlnaiion from the higher layers using the

Control Plane on the Ifo (eNB to UEi interlace.

00133] Even :I ihe TDD channel already supports more t'lcxible ACKANAUK asgignmvnt and bundling, it is recommended to provide fnrthei flexibility in AUK/NACK scheduling.

oves topping will take place m the nupframe:-; involving transition Bam FDD to TDD. [00133] To avoid transmission during one of the overlapping subfratne-f·., a neu message ran be used m indicate, in which Ul. subframe the ACK/NACK for a given downlink sitbirame should be transmitted.

100136] kt any ease, it is desirable died the FDD and TDD base stations coordinate. Uf.

allocation of the dmerfrcquenxy resources to FDD or TDD l-’DSCH. PUCCH and PRaCU iphy.stenl random access channel), such that each base station will be able independently to

Th the nter-eNR coordination can lake place on the imer-eNB X2 or Xn interface (the .second is used only for dual coiineotis'ity). which’ may be enhanced with information elements: described above.

DiO’crent channel width for FDD and TOO use [00138] In general the channels used in FDD operation are w-der than those used FDD. This difference in the shannd width -mpho that uphnk transmissions should different ehatmel widths when they Cue multiplexed on art FDD DE channel, and it may be uecc»sary to switch the chan-sei filtots, within the UF. Te radio module as function of the toe channel width per subfranm,

TDD of carrier nggreguthm in uplink (00139] For the aggregation of the uplink FDD-only or TDD-only earners, a UE should use only the relevant subframes, as assigned to each UE for each duplex mode, [00140] The Peed fprimary ceiL carrying control and eventually data information) and Seed (secondary end, carrying data and eventually cuntroi mformatiom cat- be assigned on any of the aggregated carriers.

Variable DLtUl, traffic^vmuwv op diihment component currim [00141] Each component carrier can use a differ,mt traffic asymmetry, hi TDD this asymmetry may he reflected m different Frame configurations for DL and UL, subframes. In both FDD and TDD, the number of subframes actually used for the uplink traffic may differ between the component carriers, [001.42] The FDD base station, based on the DL-UL configuration information provided by the TDD base station, will allocate its UL subframes so as to allow the multiplexing of the TDD subframes within its UL frequency channel,

UE ,transmission power [00143] Due to the different propagation paths between some component carriers or doe to other scheduling considerations, the UE transmission power may be diffemtn on each component carrier, creating potential interference problem between the component carrieis. [00144] When such a problem appears. it is possible to mitigate it by scheduling UEs operating on difterem component carriers hw using ''miliar transmitting powers in the same subframe.

[00145] Tri support the above scheduling method, base stations should mcchimge, information regarding power allocation per PR8 or per subhand in a specific UL subframe and eventually include in the exchanged information the specific UE ID.

[00.1.40] A base station knowing the power allocation of the other base station will be able to correctly schedule the UEs in order to minimize the imer»carrier imerference,

Resotitee split In frequency domain [00147] The resource split between the two base stations can take place in the time domain, as illustrated above. This approach requires synchronization between base stations.

1'00148] /Another possible approach is m make the resource split in the frequency domain, with each base station using onhogotsal PRBs <,r subbands. Thus approach will nm require synehroinzaiion, but may be prone to rempreva’ interference in ease ot dual ccnnoed’viiy.

[00140] Thia sort of operation ss illustrated jo Figure 13. as-mmlng that both base stations use she same, channel width, [00150] In ‘his figure the PUCCHs nf eNBI and eNB2 are represented respectively by dliecation.s 1301, 1302 and 13'03 and 13U-I within the same frequency chasm?!. while rhe

PIJSCU is:

1'0015 π iepo.-seuk'd by the tesmtrec blocks 1303 and LW,

Alternatively separate ncqueucy channels car, be u-'ed for each eNB.

When the channel widths ate differed, a more complicated resource the tinie-trequcncy A’sources for PUCCHs and PUSCHs

UEs not fiup»rl hie AUK/NAUK [00154] .A legacy HE may commumtate v-lth tm. FDD or FDD bate stations in the legacv mode, wen the emtditbm that both DI and I L tmffic. s'cheduhn,e bv foe rerucctivr ·»· y * λ eNB Will provide oprianon-il condir-mts font wtil m<t teqmre nets UF cepabthties. (00155] Po: example, if the DLdata mwanssmn to there I Es occurs oulv in xubtrame' in which the bl. FDD

ACK/NACK can be tians-mtted based on me tbui rubframc ddav tide for FDD or based on she ACK-'NACK tules tm TDD. these will be tall compbance with the legacy PDD oi

TDD .system,

V E* U Is eom mu nteat I nn [00156] UE-UE cofumtmication will bi:

channel ol cither the FDD or the TDD system. For this purpose, one of the UE;·: will have to quit its stnving cell for the duration of the UF.-UE communication [00I57J By usmg features of the present invention, ;t IJE sejvrd bs an FDD base station can comnnmicaie with a Id served b\ a TDD base .station while each UE remains connected to its* msn w reg base stiuon

Traffic asymmetry lit FDD anti TOD cells [00158] Traffic asymmetry can he differ,

FDD cell can be configured for downlink-centric asvrnmetjy, while foe Ί DD cell can he

2.5 used for ceils transmitting machine-type communication or different events (sports events, shows, etc.)

It is required that the TDD frame UL-DL configuration on each carrier will be exchanged with the FDD base station.

MnHj-RA.T (Radio Arms I’echnolug.v)

Embodiments of invention can us? different technologies in the FDD and TDD base stations, For example the FDD base station can use I1SDPA. while fee TDD base station exes 1.ΊΈ.

[00160] The condition for such combined operation is that the TDD base station frame structure allows interleaving into the subframes made- available by the FDD system or, even belter; that the FDD base station, based on the DL UL configuration information provided by the TDD base station, will allocate its UL subframes so as to allow the multiplexing of subframes transmitted in accordance with the other technology.

UE behavior [00161] To communicate with a TDD cell operating in an UL FDD frequency channel, the UE should be able, as a first step, to execute a cell search in that frequency channel. i,e., to acquire time and frequency synchronization with the TDD cell, in LI E this process uses fee primary and secondary synchronization signals, The next steps are decoding of the system mforrmnion contained in the Master Information Block and a number of System Information Blocks and connection to a serving cell.

[00162] l^;or perforating Carrier Aggregation, the UE should he able to change its behavior in the same, radio frame, so as to support, depending on the operation mode: [88163] A. Downlink reception in a TDD cell and uplink transmission in a FDD cell in he same radio frame and on the same radio channel.

[601.64] B. Downlink reception and uplink transmission in a FDD cairiei-aggregated mode.

[80165] C. Multiplexed uplink lransrafo:fom to dilforcnt colls, which may be essenthiliy FDD cells or a mix of FDD and TDD cells.

[80.1.66] If the cells in the above description are not collocated, the same operation modes apply for dual Connectivity.

[00167] hi order to coordinate l-iter-cdl TDD FDD imerference fm mixed-channel timge. n is desirable to enhance the LTE X2 messages (eNB-eNB) tmd/c-r the management messages and/or over-the-air cNB communications. by introducing information elements such as:

[001681 A. Request from a now eNB to the incumbent eNB to accept its cell operation within the UL frequency*, possible parameters? each eNB identifier. requested bandwidth, requested number of subframes, DL-4JL split, max. power, synchronization eapubsiliict:. pathloss iiilbrmatioi’ based on the DL, reception.

[06169] B. Acceptance of the above request by the incumbent eN8, while indicating the allowed BW. mas. power, allowed number of subframes, allowed DL:UL split, selection oi synch ron i za 11 on mode, [00170] C. Confirmation by the new eNB of the start of activity based on the present time or a specified future time, while indicating the eNB identifier, type of confirmation (Yes, No), start time information.

[991.71] D, Request from an incumbent eNB to -he new cNB to cease operation within its DL frequency or to change parameters of its operation, such as max. power, etc,; ptwslble information; eNB identifiers, type of rerpie-st, list ofi parameters’ trad possibly preferred values.

[(MH 72] E. Time offset between the start of the FDD frame of the incumbent eNB and the start of the TDD frame of the new e'NB: possible information: eNB Identifiers, time offset. how the time offset was determined, [00173] F, Allocated UL subfrnme for D2D operation; possible infoi'matiom identifier of the cNS snaking available such subframe. subframe number within die eNB frasno.

[00174] G. TDD configuration used i?y the TDD eNB operating irs the UL FDD band. Possible information: TDD eNB identifies; DL:UL configuration index, transmission power, frequency channel identifier.

[00175] H. Request from an eNB to the other eNB in CA or to the MeNB in dual cimnecttvity to accept its partial or foil operation w-thiu the UL frequency; possible parameters are: eNB identifier, bandwidth. requested number of subframes, syncbronizatloti capabdittes;. flexible PUCCH assignment support, preferred subframes indicators.

[00176] h Acceptance of the above jv.quc.st by the incumbent eNB, while indicating its eNB identifier, she allowed BW. allowed number of subframes, acceptable suhfrasne assignment, the PRBs assigned to the PUCCH in each subframe.

by the new eNB of the start of activity at the present time m a specif it’d future time.

:00178] K, Request from an incumbent eNB to the new cNB to cease operation within its 1.:1. frequency ^or 1° change parameters of It operation, such as subframe or PRB assignment.

500(79] I,. Scheduling information per subframe and componem earner, tnetiufing cNR identifier, subframe number. PRBs or subframes, used UE power, possibly UE. identifier. [0(080] M, Scheduling information for flexible UCI II·, to be exchanged with UL o^er tiie Un ititeiface icNB o Ul·!, especially ACK/NACK. hcbeduliug and over the eNB ebffi

X2 or Xu interfaces.

subframe allocation in -he 'FDD base station, including eNB identifier and TDD ira?

ne configuration mdex.

[(MH82] O. UE cmtki indicate to each base station the different time advances or the.

100183]

The resource fillairatioii per subframe is not needed when the two base stations share fac resources m frcqueitey domain, [00184] When foe traffic characieristiCs change, tbc TDD b,n:e station may change she Configuration, as indicated tn 3GPP TS 36.211 Release 11 for Fame typo 2 In such a err the TDD base station may request a change of resource allocation. The same configuration change may occur due to foe changing pejccotage of UL traffic in the FIJI) of IDI) base station As result, the entire resource allocation in 'die UL frame may be rnmegotiateu

It will he appreciated that the embodiments described ah*'vt am cited by way ol example.

limited to what h;i-: be/m partieitfariv shown and

J, y combinations and .snhcombinatnms o scope of the present invention includes both he varitm.s feature¹- described hereinabove, as well as variations and modifications thereof which would occur to persons skilled reading the foregoing description and which are net disclosed in the prior art,

Claims

CLAIMS:

1.

A method for communication, comprising:

configuring at least one first base station or at least one first radio head tor communicating over the air with at least one first user equipment (UE) in a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a flj'st set of time resources in a first frequency range and at least one uplink channel comprising a second set of time resources in a second frequency range.

which is disjoint from the first frequency range;

assigning at least one first time resource of the at least one uplink channel for uplink communications of the at least one first UE and at least one second time resource of the at least one uplink channel, which is different from the at least one first time resource, to downlink communications of at least one second UE in the second frequency range;

communicating over the air with the at least one first UE in the FDD mode, by using the assigned at least one first time resource for transmitting information from the at least one first UE to the at least one of the first base station or the first radio head: and communicating over the air with the at least one second UE by transmitting, front at least one second base station or at least one second radio head, downlink information using die assigned at least one second time resource in the second frequency range.
2.

The method according to claim 1, wherein communicating over the air with, the at least one second UE comprises transmitting to the at least one second UE downlink information from the at least one first base station or at least one first radio head and from the at least one second base station or at least one second radio head by using concurrently at least one third time resource in the first set of time resources in the first frequency range and the at least one second time resource of the at least one uplink channel in the second frequency range, wherein the at least one third time resource is used by the at least one first base station or by the at least one first radio bead and th· at least one second time resource is used by the at least one second base station or by the at least one second radio head.

'Γ

The method according to claim 2, wherein the second base station is included within the first base station and communicating over the air with the at least one second UE comprises transmitting the downlink information from at least two radios or two radio heads of the first base station by using concurrently the at least one third time resource in the first set of lime resources in the first frequency range and the at east one second time resource of the at least one uplink channel in the second frequency range.

4.

The method according to claim 2, wherein communicating over the air comprises communicating with the at least one second UE concurrently in both time domain duplexing (TDD) mode and FDD mode

The method according to claim 4, wherein communicating in the TDD mode comprises detecting an overlap between the at least one first time resource that is assigned for the FDD uplink communication and the at least one second time resource that is assigned for TDD downli nk communication, and inhibiting uplink or downlink transmissions within at least one of the first and second time resources.

The method according to time resource of the at least one uplink channel to the downlink communication comprises exchanging communications between the at least, one first base station and the at least one second base station or between a provisioning entity and at least one of the: at least one first base station, at least one second base station, at least one first radio head, and at least one second radio head in order to define an assignment to the downlink communications of the at least one second time resource.

The method according to claim 6, wherein assigning the at least one second time resource comprises selecting the at. least one first time resource for use in FDD uplink communication and the at least one second time resource for downlink communication so as to minimize a co-channel or adjacent channel interference between the FDD uplink communication and the downlink communication on at least one channel in. the second frequency range.

8.

The method according to claim 1, wherein the transmitted power within al least one second time resource of the at least one uplink channel in the second frequency range is reduced to zero,

9.

The method according to claim 1, including.lransmitti.ug by the at least one first

UE of an acknowledgment (ACK) or NACK as feedback information relating to a reception of user information transmitted in the at least one downlink channel in a way x y that avoids using the at least one second time resource.

10. The method according to claim 9, wherein avoiding the use of the at least one second time resource is achieved by receiving in the at least one first time resource the at least one uplink channel of at least two accumulated ACKs or NACKs as the at least one first UE and relating transmissions of user information in at least two time resources of the first set of time resources of the downlink channel.

11. The method according to claim 9. wherein avoiding the use of the at least one second time resource is achieved by appropriate scheduling of transmissions of user information to the first UE in the at least one downlink channel.

12. Communication apparatus, comprising:

at least one radio, which is configured to communicate over the air with at least one first user equipment (UE) in a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first frequency range and at least one uplink channel comprising a second set of time resources in a second frequency range, which is disjoint from the first frequency range;

and a control block, which is configured to enable the communication over the air first time resource, in the at least one channel in the second frequency range, for receiving information from the at least one first UE, wherein the first time resource is different from at least one second time resource used for downlink communi cation of a second UE with a second apparatus in the at least one channel in the second frequency range and wherein the control block is further configured to enable reception over the air in the at least one first time resource of at least two acknowledgments (ACKs) or

NACKs as feedback information transmitted by the first UE and relating to downlink information transmitted over the air by the apparatus in at least two time resources in

13. The apparatus according to claim t-vz allocate or to receive from a base station at least one second time resource in the range for downlink communication with at least one second UE.

The apparatus according to claim 13, wherein the control block is configured to communicate with the UE tor transnutting downlink information at least one second time resource tn the at least one channel in the second frequency range concunremly with at least one third time resource in the first set of time resources in the first frequency range.

15. The apparatus according to claim 12, wherein the control block is configured to resource.

16. The apparatus according to claim 12, wherein the control block is configured to receive at least two accumulated acknowledgments (ACKs) or NACKs as feedback information transmitted by the at least one first UE and relating to transmissions of user information in at least two time resources of the first set of time resources of the at least one downlink channel.

17. Communication apparatus, comprising:

at least one radio, which is configured to communicate over the air with at least one base station or at least one radio head using frequency channels initially defined for a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first frequency range and at least one uplink channel comprising a second set of time resources in a second frequency range, which is disjoint from the first frequency range, wherein communi eating with the at least one base station or at least one radio head includes a transmission operation using at least one first time resource ofthe at least one uplink channel and a reception operation using at least one second time resource assigned for downlink communication in the at least one uplink channel wherein the second time resource is different from the at least one first lime resource:

a signal processing block, configured to acquire synchronization with the at least one base station or al least one radio head in the FDD mode; and the at least one base station in the FDD mode and to enable downlink communication to be carried out over the air with the at least one base station using the assigned at least one second time resource in the second frequency range.

18. t:

te apparatus according to claim 17, wherein the control block is configured to transmit to the base station at least two accumulated acknowledgments (ACKs) or

NACKs as feedback information relating to transmissions of user information in at least two time resources belonging to the first, set of time resources ofthe downlink channel.

19. Communication apparatus, comprising:

<x«at least one radio, which is configured to communicate over the air with al least one second user equipment (UE) in a time domain duplexing (TDD) mode using at least one uplink frequency channel initially defined for a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first, frequency range and al least one uplink channel comprising a first frequency range, and wherein the second set of time resources comprises at least one first time resource assigned for uplink FDD communication of at least one first UE and at least one second time resource assigned for downlink communication in the at least one uplink frequency channel, wherein the second lime resource is different from the at least one first time resource: and a control block, which is configured to enable communication over the air in the TDD mode of the apparatus will· the at least one second UE in the at least one uplink frequency channel while using the at least one second time resource for the downlink TDD communication.

20. Communication apparatus comprising:

at least one radio, which is configured to communicate over the air with at least one base station or at least one radio head in a time domain duplexing (TDD) mode.

duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first frequency range and at least one uplink channel comprising a second set of time resources in a second frequency range, which is disjoint from the first frequency range, and wherein the second set of time resources comprises at least, one first time resource assigned for uplink FDD communication and at least one second time resource assigned for downlink comm uni cation in. the at least.

one uplink frequency channel, wherein the second time resource is different from the at least one first time resource' a signal processing block, configured to acquire synchronization with the at least one base station in the TDD mode; and downlink communication to be carried out over the air by the at least one base station or at least one radio head using the assigned at least one second time resource in the second frequency range.

21. A system for communication, comprising:

at east first and second user equipment (UE);

east one first base station or at. least one first radio head, which is configured to communicate over the air with at least the first user equipment (UE) in a frequency domain duplexing (FDD) mode, which defines at least one downlink channel comprising a first set of time resources in a first frequency range and at <4v east one uplink channel comprising a second set of time resources in a second frequency range, which is disjoint from the first frequency range, including at least one first time resource o first UE in die second frequency range; and at least one second base station or at least one second radio head, which is configured to communicate over the air with the second user equipment (U E) in a time domain duplexing (T DD) mode, and to allocate at least one second time resource of the at least one uplink channel, which is different from file at least one first time resource, to downlink communication of the second UE for receiving downlink information from the at least one first base station or at least one first radio head and the at least one second base station or the at least one second radio bead by using concumently at least one third time resource of the first set of time resources in the first freuuencv range and the at least one second time resource in the second frequency range.

22. The system according to claim 21, wherein the al least one first base station or ·&

the at least one first radio head is further configured to receive at least two accumulated acknowledgments (ACKs) or NACKs as feedback information transmitted by the at resources of the first set of time resources of the downlink channel.