DESCRIPTION

Title of Invention

SYSTEM AND METHOD FOR AN ENHANCED CARRIER AND ENHANCED CONTROL CHANNEL

Technical Field

[0001]

The present invention generally relates to enhancing a communication carrier and a control channel in an advanced communication network.

[0002]

The present invention has particular, although not exclusive application to the design of control regions for common search spaces, control regions for UE specific search spaces having resource mapping for a Physical Hybrid Automatic Repeat-reQuest (ARQ) Indicator channel, and operational procedures that shall assist system information acquisition, connection establishment, and the transmission and reception of a data channel on the enhanced carrier.

Background Art

[0003]

The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

[0004]

In the 3rd Generation Partnership Project (3 GPP), Radio Access Network (RAN) Plenary #57 meeting in September 2012, re-starting og the Work Item (WI) of New Carrier Type (NCT) was approved. At the RAN Plenary #58 meeting in December 2012, this WI was again updated. This WI was approved in order to meet the following aims:

1. to enhance system spectral efficiency,

2. to improve support of HetNet deployments, and

3. to reduce network energy consumption.

[0005]

It is recognized that these aims can be achieved by enhancing the transmission of data and control on the NCT by means of minimizing legacy control signaling. Common reference signals reduce the interference and overhead level at low-to-medium loads, allowing for higher end-user throughput and improving system spectral efficiency. The foregoing seems especially beneficial at the cell edge of a homogeneous deployment scenario, in a cell range expansion zone of a heterogeneous deployment scenario, and for the enhanced local area access in the deployment scenario of low-power nodes with or without coverage of an existing macro-node layer. These scenarios are graphically illustrated in Fig. 1 where Fl is the carrier frequency of a legacy Long Term Evolution (LTE) carrier and F2 is the carrier frequency of the NCT carrier. Fl and F2 can be intra-band or inter-band.

[0006]

Furthermore, the NCT design can result in reducing network energy consumption (e.g. to minimize the cost of the energy to operate the radio network or to facilitate new deployment scenarios). Network energy efficiency is to a large extent an implementation issue. However, specific features of the specification may enable enhancements in energy efficiency (e.g. by allowing base stations to turn off transmission circuitry when there is no data to transmit).

[0007]

In regard to deployment scenarios, a NCT may be used in conjunction with carrier aggregation of a legacy LTE carrier, in case the targeted spectrum block does not allow for a standalone operation (e.g. an unpaired frequency-division duplex (FDD) spectrum). The foregoing is illustrated in deployment scenarios la, lb of Fig. 2.

[0008]

Furthermore, a NTC may be used in a standalone mode (e.g. in time-division duplexing

(TDD) or paired FDD blocks). The foregoing is illustrated in scenario 2c of Fig. 3B.

[0009]

To some extent, a NCT may be used in conjunction with carrier aggregation of a legacy LTE carrier, in case the targeted spectrum block allows for a standalone operation. The operator may desire deployment of a NCT to improve system throughput, especially at the cell edge or sector boundary. The foregoing is illustrated in scenarios 2a and 2b of Fig. 3 A and Fig. 3B.

[0010]

When a NCT is aggregated with an adjacent legacy carrier, synchronization might be provided by the legacy LTE carrier. In this event, the synchronization signal shown in Fig. 2, Fig. 3 A and Fig. 3B is not used and could be turned off to conserve a base station's energy. At least in the event of aggregating non-adjacent carriers and in the event of a standalone operation, a NCT provides a proper synchronization signal for discovery and time/frequency tracking. Summary of Invention

Technical Problem

[0011]

As illustrated in scenario la of Fig. 2 and scenario 2a of Fig. 3 A, a NTC with "Cross Carrier Scheduling" is realizable. In these scenarios, the NTC and legacy LTE carrier will be deployed as a SCell (Secondary Cell) and a PCell (Primary Cell) respectively. Using cross-carrier scheduling will further stretch the scarce resource on the PCell to provide Radio Resource Control (RRC) signalling and associated control signalling supporting the transmission and/or reception of physical channels on the SCell. This problem is magnified in the case of TDD systems because associated control signalling for more than 1 subframes are transmitted on a single sub frame in downlink and/or uplink. Therefore, it is desirable that a NCT possess features that allow it to operate independently with mimmal signalling assistance being required from a legacy LTE carrier to which it is aggregated. Solution to Problem

[0012]

According to one aspect of the present invention, there is provided a new carrier type (NCT) subframe including:

a first control region occupying a first frequency band and for use in controlling a common search space,

a second control region occupying a second frequency band and for use in controlling a user equipment (UE) specific search space; and

a data region occupying a further frequency band and for use in a downlink shared channel transmission.

[0013]

Advantageously, both the first control region and the second control region may be independently configured by a base station. The base station may dynamically configure one or several first control regions on the same downlink (DL) subframe.

[0014]

In one embodiment, none, one or more than one first control region is configured to hava a different size dynamically on a subframe basis, and the control regions are used for localized or distributed transmission independently to adapt to demand in a cell. The base station can thereby reduce the first control regions to a minimum, or even not transmit at all, to conserve power. [0015]

Advantageously, a UE may quickly and easily detect the first control region without prior signalling. Furthermore, the base station may configure the first control region targeting a group of UEs so that when a UE in this group cannot detect its first control region, it will not attempt to perform blind decoding of EPDCCH on a search space hence further conserving its power.

[0016]

Preferably, the design of the NCT subframe structure and associated operational procedures allows the NCT carrier to be flexibly deployed in conjunction with carrier aggregation of a legacy LTE carrier with or without "cross carrier scheduling", and further deployed as a standalone carrier. Accordingly, the NCT can be used as a low-power node without coverage of a macro cell.

[0017]

Preferably, the design of the NCT subframe structure allows a base station to flexibly adjust its transmission bandwidth dynamically without the issue of a UE losing a connection with it due to the missing of a control channel occurring. Hence, a base station can further conserve its power.

[0018]

The first control region, second control region and data region may be frequency multiplexed on a Physical Resource Block (PRB) pair basis. Advantageously, as the control regions and data region are frequency multiplexed in the frequency domain, they are able to support frequency domain Inter-Cell Interference Coordination (ICIC).

[0019]

According to another aspect of the present invention, there is provided a new carrier type (NCT) subframe including:

a control region occupying a frequency band and for use in controlling user equipment (UE) specific search space.

[0020]

According to another aspect of the present invention, there is provided a mapping method for mapping scrambled composite Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) symbols to Resource Elements ( ), the mapping method including the steps of: selecting a PHICH resource;

defining PHICH enhanced resource element groups (REGs) based upon the selected PHICH resource; and mapping PHICH symbols to the defined PHICH enhanced REGs within the control region of the NCT subframe.

[0021]

According to another aspect of the present invention, there is provided a communication system including:

a legacy Long Term Evolution (LTE) base station supporting a legacy LTE carrier; a new carrier type (NCT) base station supporting a NCT carrier including subframes, each subframe including a control region occupying a frequency band and for use in controlling a user equipment (UE) specific search space; and

a UE supporting both the legacy LTE carrier and the NCT carrier.

[0022]

According to another aspect of the present invention, there is provided a communication system including:

a new carrier type (NCT) base station supporting a NCT carrier including subframes, each subframe including a control region occupying a frequency band and for use in controlling a user equipment (UE) specific search space; and

a UE supporting the NCT carrier .

[0023]

Preferably, each subframe includes another control region occupying a frequency band and for use in controlling common search space. The UE may further support existing legacy LTE capability.

[0024]

According to another aspect of the present invention, there is provided a new carrier type (NCT) base station supporting a NCT carrier including subframes, each subframe including a control region occupying a frequency band and for use in controlling user equipment (UE) specific search space.

[0025]

The control region may be suitable for use in controlling a common search space in addition to the user equipment (UE) specific search space.

[0026]

According to another aspect of the present invention, there is provided a user equipment (UE) supporting a new carrier type (NCT) carrier including subframes, each subframe including a control region occupying a frequency band and for use in performing a user equipment (UE) specific search. Advantageous Effects of Invention

[0027]

According to the present invention, it can be achieved that a NCT possess features that allow it to operate independently with minimal signalling assistance being required from a legacy LTE carrier to which it is aggregated.

Brief Description of Drawings

[0028]

Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[Fig. 1]

Fig. 1 is a schematic diagram showing New Carrier Type (NTC) Deployment scenarios in accordance with an example;

[Fig. 2]

Fig. 2 is a schematic diagram showing Deployment Scenarios of NCT for an unpaired FDD spectrum;

[Fig. 3A]

Fig. 3 A is a schematic diagram showing Deployment Scenarios of NCT for TDD or a paired FDD spectrum;

[Fig. 3B]

Fig. 3B is a schematic diagram showing Deployment Scenarios of NCT for TDD or a paired FDD spectrum;

[Fig. 4]

Fig. 4 is a schematic diagram showing a Legacy LTE carrier compared with a NCT carrier in accordance with an embodiment of the present invention;

[Fig. 5]

Fig. 5 is a schematic diagram showing a NCT subframe structure in accordance with an embodiment of the present invention;

[Fig. 6]

Fig. 6 is a schematic diagram showing a wireless communication system in accordance with an embodiment of the present invention;

[Fig- 7]

Fig. 7 is a schematic diagram showing a Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) Resource Definition, Normal CP on PRBs without cell-specific reference signals (CRS) and with Channel-State Information reference signal (CSI-RS), in accordance with an embodiment of the present invention;

[Fig. 8]

Fig. 8 is a schematic diagram showing a PHICH Resource Definition, Normal CP on PRBs with CRS and without CSI-RS, in accordance with an embodiment of the present invention;

[Fig. 9]

Fig. 9 is a schematic diagram showing a PHICH Resource Definition, Normal CP on PRBs without CRS and without CSI-RS, in accordance with an embodiment of the present invention;

[Fig. 10]

Fig. 10 is a schematic diagram showing a PHICH Resource, Extended CP on PRB with CSI-RS and with CRS (250a) or without CRS (250b), in accordance with an embodiment of the present invention;

[Fig. 11]

Fig. 11 is a schematic diagram showing a PHICH eREG Definition, normal subframe on

PRB without CRS (300a) and with CRS (300b), in accordance with an embodiment of the present invention;

[Fig. 12]

Fig. 12 is a schematic diagram showing PHICH group to PHICH eREGs mapping using a localized mapping method in accordance with an embodiment of the present invention;

[Fig. 13 A]

Fig. 13A is a schematic diagram showing PHICH group to PHICH eREGs mapping using a distribution mapping method in accordance with an embodiment of the present invention; [Fig. 13B]

Fig. 13B is a schematic diagram showing PHICH group to PHICH eREGs mapping using a distribution mapping method in accordance with an embodiment of the present invention; [Fig. 14]

Fig. 14 is a schematic diagram showing PHICH groups to PHICH eREGs mapping using a distribution mapping method and having PRB pairs without CRS in accordance with an embodiment of the present invention;

[Fig. 15]

Fig. 15 is a schematic diagram showing PHICH groups to PHICH eREGs mapping using a distribution mapping method and having PRB pairs with CRS in accordance with an embodiment of the present invention;

[Fig. 16]

Fig. 16 is a schematic diagram showing PHICH group to PHICH eREG mapping using a distribution mapping method on mixed PRB pairs with and without CRS in accordance with an embodiment of the present invention;

[Fig. 17]

Fig. 17 is a schematic diagram showing mapping of a symbol quadruplet z^i) to REs on predetermined eREG ^pmCH with index (e) in accordance with an embodiment of the present invention; and

[Fig. 18]

Fig. 18 is a schematic diagram showing mapping of a symbol quadruplet z^i) to REs on predetermined eREG ^pmCH with index (e) in accordance with an embodiment of the present invention.

Description of Embodiments

[0029]

In accordance with an embodiment of the present invention, the NCT possesses features that allow it to operate independently with minimal signalling assistance required from a legacy LTE carrier to which it is aggregated. The basis of the associated control signalling includes:

Downlink scheduling assignments, including information required for the wireless terminal to be able to properly receive, demodulate, and decode the DL-SCH (Downlink Shared Channel) on a component carrier,

Uplink scheduling grants informing the wireless terminal about the resources and transport format to use for uplink UL-SCH (Uplink Shared Channel) transmission, and

Hybrid-ARQ acknowledgements in response to UL-SCH transmissions.

[0030]

In addition, the downlink control signalling is also used for the transmission of power-control commands for power control of uplink physical channels, as well as for certain special purposes such as MBSFN notifications.

[0031] Control signalling cases for various deployment scenarios are described below.

[0032]

(Case 1)

In reference to deployment scenario la of Fig. 2 for a NCT on an unpaired FDD spectrum, with cross carrier scheduling "enable", legacy LTE carrier (PCell) provides the following services to a New Carrier Type (NCT) (SCell):

Associate control signalling includes downlink scheduling assignments for the reception and decoding of the DL-SCH/PDSCH (Downlink Shared Channel) on NCT carrier (SCell),

- Uplink control channel on legacy LTE carrier (PCell) to provide services for carrying

Hybrid-ARQ acknowledgements in response to DL-SCH reception on the NCT carrier (SCell) at the wireless terminal as well as CSI feedback state information measured on the NCT carrier (SCell).

[0033]

(Case 2)

In reference to scenario 2a of Fig. 3 A for a NCT on a paired FDD spectrum or unpaired TDD spectrum, with cross carrier scheduling "enable", the legacy LTE carrier (PCell) provides the following services to a NCT carrier (SCell):

Associate control signalling includes :

— Downlink scheduling assignments for the reception and decoding of the

Downlink Shared Channel (DL-SCH/PDSCH) on the NCT carrier,

Uplink scheduling grants informing the wireless terminal about the resources and transport format to use for uplink UL-SCH (Uplink Shared Channel) transmission,

Hybrid-ARQ acknowledgements in response to UL-SCH transmissions on a SCell, and

the transmission of power-control commands for power control of PUSCH Uplink control channel on the PCell to provide services for carrying Hybrid-ARQ acknowledgements in response to DL-SCH/PDSCH reception on the SCell at the wireless terminal as well as CSI feedback information measured on the NTC carrier.

[0034]

(Case 3)

In reference to scenario lb of Fig. 2 for an unpaired FDD spectrum, with cross carrier scheduling "DISABLE", legacy LTE carrier (PCell) provides the following services to a NCT carrier (SCell): RRC signaling to indicate the PRBs that are allocated for the transmission of EPDCCH forming a terminal UE specific search space,

Uplink control channel on the PCell to provide services for carrying Hybrid-ARQ acknowledgements in response to DL-SCH/PDSCH reception on the SCell at the wireless terminal as well as CSI feedback information measured on the SCell.

[0035]

In this case, the NCT carrier provides associated control signalling that includes:

Downlink scheduling assignments for the reception and decoding of the

DL-SCH/PDSCH on its own carrier component.

- The associated control signalling is sent using existing state-of-art Enhanced Physical

Downlink Control Channel (EPDCCH) within terminal or User Equipment (UE) Specific Search

Space (USS).

[0036]

It is apparent that the foregoing approach reduces the control signalling load on the legacy LTE carrier (PCell).

[0037]

(Case 4)

In reference to scenario 2b of Fig. 3B below for a paired FDD block or TDD, with cross carrier scheduling "DISABLE", the legacy LTE carrier (PCell) provides the following services to a NCT (SCell):

RRC signaling to indicate the PRBs that is allocated for the transmission of EPDCCH forming a terminal UE specific search space,

Uplink control channel on the PCell in the absence of scheduled PUSCH on the same subframe, to provide services for carrying Hybrid-ARQ acknowledgements in response to DL-SCH reception on the SCell at the wireless terminal as well as CSI feedback information measured on the SCell.

[0038]

In this case, the NCT SCell has to provide associated control signalling that includes: Downlink scheduling assignments for the reception and decoding of the

DL-SCH/PDSCH on the NCT carrier (SCell),

Uplink scheduling grants informing the wireless terminal about the resources and transport format to use for uplink UL-SCH (Uplink Shared Channel) transmission,

Hybrid-ARQ acknowledgements in response to UL-SCH transmissions, and

the transmission of power-control commands for power control of PUSCH. [0039]

In this case, the identified associated control signalling except "Hybrid-ARQ

acknowledgements in response to UL-SCH transmissions" could be sent using existing state-of-art EPDCCH within terminal or UE Specific Search Space (USS). It is apparent that this approach reduces the control signalling load on the legacy LTE carrier - PCell.

[0040]

On a legacy LTE carrier, according to the prior art Release 8, 9, 10 and 11 LTE, each subframe can be said to be divided into a "control region" (11a) followed by a "data region" (12a) in time as illustrated as a structure 10a in Fig. 4. A NTC can be used in conjunction with carrier aggregation of a legacy LTE carrier, where the NCT and legacy LTE carrier operate as a SCell and a PCell respectively. From the discussion of case 1 , case 2, case 3 and case 4 above it can be seen that "control region" per current state-of-art (the control region 1 la in the structure 10a) is not required to be used or utilized on the NTC carrier because the prior art EPDCCH USS can efficiently handle the required "associated control signalling" except "Hybrid-ARQ acknowledgements in response to UL-SCH transmissions". Therefore, it is desirable:

to remove the time multiplexing "control region" on the NCT subframe structure to maximize the physical resource utilization, and

to introduce a frequency multiplexing "control region" on the NCT subframe structure as illustrated by a structure 10b in Fig. 4.

[0041]

According to the new subframe structure for the NCT carrier illustrated in the structure 10b of Fig. 4, the "control region" l ib and "data region" 12b are frequency multiplexed. The control region 1 lb is mapped on a predetermined pair of Physical Resource Blocks (PRBs) or pairs of PRBs. Pairs of PRBs allocated for downlink control signalling transmission from a base station could be (1) a localized transmission to utilize beam-forming gain and/or (2) distributed transmission to utilize frequency diversity gain. The design of the NCT subframe structure is discussed in more detail below to address the issue of the missing DL control signalling design components including "Hybrid-ARQ acknowledgements in response to UL-SCH transmissions".

[0042]

(Case 5)

In reference to scenario 2c of Fig. 3B for a paired FDD block or TDD, a NCT could be deployed as a low-power node without coverage of an existing macro-node layer. This means a NCT carrier could NOT be used in conjunction with carrier aggregation of a legacy LTE carrier unlike in the Cases 1 , 2, 3 and 4 discussed above. In the present case 5, a NCT carrier is operating as a standalone PCell to provide a necessary synchronization signal and associated downlink control signalling to assist the following:

1. System information acquisition,

2. Connection set-up including network-initiated connection setup and Mobile Terminal initiated connection setup,

3. Downlink scheduling assignments for the reception and decoding of the

DL-SCH PDSCH on the NCT component carrier,

4. Uplink scheduling grants informing the wireless terminal about the resources and transport format to use for uplink UL-SCH (Uplink Shared Channel) transmission,

5. Hybrid- ARQ acknowledgements in response to UL-SCH transmissions, and

6. the transmission of power-control commands for power control of uplink physical channels including PUCCH and PUSCH.

[0043]

According to Prior Art LTE's Release 8, 9, 10 and 1 1 standards, it is known that a terminal could acquire a cell Master Information Block (MIB) without using downlink control signalling, and the same design can be used on the present NCT design.

[0044]

According to recent Prior Art Release 11 LTE, it is known that the Prior Art EPDCCH was designed for a terminal or UE Specific Search Space (USS) only. That is when a terminal is in RRC-CON ECTED mode; it will be informed, via Radio Resource Control (RRC) signalling, of the location of a PRB pair(s) in a sub frame that EPDCCHs forming a UE specific search space are mapped on. From the received EPDCCHs, the terminal can determine a UE specific space that is supposed to monitor for scheduling assignment/grants. Otherwise, a terminal does not have prior knowledge of EPDCCHs PRBs pairs' location.

[0045]

According to Prior Art LTE's Release 8, 9, 10 and 11 , a common search space (CCS) was also specified in addition to terminal/UE specific search spaces. A common search space is "common", and all terminals in a cell monitor the CCEs (Control Channel Elements) in the common search space for control information. The Common search space defined in Prior Art Release 8, 9, 10 and 1 1 LTE is primarily for dynamic transmission of various system messages (i.e. system information) and could be used to schedule individual terminals. According to Prior Art Release 8, 9, 10 and 11 LTE, a common search space is mapped on PDCCHs within a legacy control region 11a in Fig. 4. [0046]

Removing the legacy control region 1 la on the NTC, as per the discussion prior to case 5 above, would not make the NCT in case 5 operable because the terminal/UE cannot acquire cell system information. This information cannot be acquired due to the dynamic scheduling of system information, and lack of a common search space on which the terminal can perform blind detection for associated control signalling of the dynamic scheduling of system information. Additionally, removing the legacy control region on the NTC would remove the region for the mapping for PHICHs (Physical Hybrid- ARQ Indicator Channel) that is required for carrying Hybrid-ARQ acknowledgements in response to UL-SCH transmissions from a terminal UE.

[0047]

FIRST ASPECT OF EMBODIMENT

Thus, the 1st aspect of this embodiment is the design of NCT's downlink subframe structure that possesses the following characteristics:

1. enhanced dynamic scheduling of system information inherited from state-of-art legacy LTE,

2. possibly smallest common search space for a terminal to process,

3. dynamic scheduling of a common search space control region to enable frequency interference coordination,

4. mechanism for terminal to perform self-detection of the common search space control region which may be dynamically reconfigured, removed or added from subframe to subframe, and

5. Dynamic resource allocation for Hybrid-ARQ acknowledgements in response to UL-SCH transmissions from at least one terminal.

[0048]

In reference to Fig. 5, the subframe structure for the NCT carrier is exemplary illustrated as a structure 20. The time-frequency structure span across

the "Downlink Bandwidth configuration" in N downlink resource blocks ( ) (21) in frequency domain, where each resource block size ( ) in frequency domain has 12 subcarriers,

- 2 slots (22) (even slot and odd slot) in time domain.

[0049]

According to the present embodiment, the NTC subframe structure is divided into three regions in frequency-domain. The three regions are the "1st control region" (23), "2nd control region" (24) and "data region" (25). The designs of those regions are disclosed in the following paragraphs.

[0050]

(First (1st) control region)

A First (1st) control region (23) is used for the transmission of enhanced downlink control channels (EPDCCHs) that form a "common search space" on a NTC carrier, and is mapped on a pair of PRBs (Physical Resource Blocks) or multiple pairs of PRBs that are predetermined by a base station on a subframe basis.

[0051]

Pair(s) of PRBs reserved for the 1st control region can be localized (i.e. a cluster of adjacent/consecutive PRB pairs in frequency) to utilize the sectored beam-forming gain, and/or distributed to utilize frequency diversity gain. There may be more than one "1 st control region (23)" on a NCT subframe.

[0052]

In order to enable dynamic scheduling of the 1 st control region (i.e. the base station could be dynamically configured, reconfigured so as to add or remove pair(s) of PRB location on subframe basis) without prior signalling to inform terminals of the changes, and also to optimize the signal processing at a terminal, a "short code" (26) is provided in the structure (20) that is used by the base station in code-multiplexing with a part of the reference signal sequence on a PRB basis, and to assist a terminal in blind detection of the 1st control region's PRBs and the number of transmit antenna ports. The "short code" (26) is a unique orthogonal sequence, spanning across a single PRB pair that is allocated for full or partial 1 st control region transmission. The "short code" (26) has a length equal to the number of Resource Elements that are reserved for Demodulation Reference Signal (DMRS), and is mapped on a designated antenna port, in 1 PRB pair assigned for the 1st control region. The "Short code" sequenced is mapped on DMRS RE(s) first in time and then in frequency to maximize both time and frequency diversity. The information for regenerating the "short code" sequence is predefined and a priori known at a terminal. At a terminal, on a subframe, PRB pairs that carry the 1 st control region are detectable by correlation of the received sequence with a "short code" replica. It is preferred that the "short code" replica can be regenerated on a "subframe basis" using the combination of Cell-ID, SFN (System Frame Number) and subframe number or using a particular designed index received on MIB of sequence initialization and generation.

[0053]

(Second (2nd) control region) A Second (2nd) control region (24) is used for the transmission of EPDCCHs that form a terminal or UE specific search spaces. The Second (2nd) control region is mapped on a pair of PRBs (Physical Resource Blocks) or multiple pairs of PRBs that are predetermined by a base station. Pair(s) of PRBs reserved for the 2nd control region could be localized and/or distributed and a terminal would be informed the according to the prior art Release 11 LTE.

[0054]

There may be more than one "2nd control region (24)" on a NCT subframe, where each "2nd control region (24)" may be dedicated to a single terminal or a group of terminals.

[0055]

In order to facilitate "Hybrid- ARQ acknowledgements in response to UL-SCH transmissions" from a UE, Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) resources (27) can be mapped within the 2nd control region (24). The detailed corresponding information is disclosed in the 2nd part of this invention.

[0056]

(Data region )

A data region (25) is used for the transmission of physical downlink shared channels (PDSCHs). The data region (25) is mapped on a pair of PRBs (Physical Resource Blocks) or multiple pairs of PRBs that are predetermined by a base station. Pair(s) of PRBs allocated for the data region (25) could be localized and/or distributed and a terminal would be informed according to the prior art Release 8, 9, 10 and 11 LTE. The data region (25) is for the transmission and reception of a Physical Downlink Shared Channel/Downlink Shared Channel (PDSCH/DL-SCH) at a base station and the UE respectively.

[0057]

None, one or more than one first control region (23) is configured by a base station with a different size dynamically on a subframe basis and none, one or more than one second control region (24) is semi dynamically configured by the base station.

[0058]

SECOND ASPECT OF EMBODIMENT

The 2nd aspect of the present embodiment is a method of mapping a scrambled composite signal representing Physical Hybrid Automatic Repeat Request Indicator Channels (PHICHs) in a group to Resource Elements reserved for PHICHs, i.e. PHICH resources (27), on a NCT subframe. According to prior art Release 8, 9, 10 and 11 LTE, the 1-bit hybrid-ARQ acknowledgement is repeated three times, followed by BPSK (Binary Phase Shift Keying) modulation on either the I or the Q branch and spreading with a length- four orthogonal sequence. A set of PHICHs transmitted on the same set of resource elements is called a PHICH group, where a PHICH group includes eight PHICHs in the case of a normal cyclic prefix. An individual PHICH can thus be uniquely represented by a single number from which the number of the PHICH group, the number of the orthogonal sequence within the group, and the branch, I or Q, can be derived. For an extended cyclic prefix, which is typically used in time-dispersive environments, the radio channel may not be flat over the frequency spanned by a length-four sequence. A non-flat channel would negatively impact the orthogonality between the sequences. Hence, for an extended cyclic prefix, orthogonal sequences of length two are used for spreading, implying only four PHICHs per PHICH group. However, the general structure of the extended cyclic prefix remains the same as that for the normal cyclic prefix. After forming the composite signal representing the PHICHs in a group, cell-specific scrambling is applied. This part is illustrated in Fig. 7, Fig. 8, and Fig. 9.

[0059]

The resulting 12 scrambled composite PHICHs-symbols are mapped to three PHICH Enhanced resource-element groups (eREG ^PHICH ) within a "2nd control region" (24 in the structure 20) using localized mapping or distributed mapping methods according to the following disclosed steps. Both localized mapping and distributed mapping are allowed on different "2nd control regions" in the same NCT subframe structure.

[0060]

(Step 1 - PHICH resource selection)

Examples are illustrated in Fig. 7, Fig. 8, and Fig. 9 for normal CP NCT subframe (200(a), 200(b), and 200(c)). On pairs of PRBs (205, 206 and 207) that are allocated for the "2nd control region" (24), select at least one orthogonal frequency-division multiplexing

(OFDM) symbol (210) that is around and closest to the OFDM symbols, and that has 1 st

Demodulation Reference Signal (DMRS) (208) being mapped on, for a PHICH resource.

[0061]

The OFDM symbol (210) selected for the PHICH resource does not have CSI-RS (209), or it is reserved for synchronization signal mapping.

[0062]

The OFDM symbol(s) (210) selected for the PHICH resource may or may not contain

CRS-RE (211).

[0063]

In reference to Fig. 10 for an extended CP NCT subframe, the same approach is applied for an extended CP NCT subframe and OFDM symbols (254) are selected as PHICH resources in structure 250(a) with cell-specific reference signals (CRS) and structure 250(b) without CRS.

[0064]

(Step 2 - PHICH Enhanced Resource-element groups (eREG ^PWCH ) definition)

The PHICH Enhanced Resource-element groups (eREG ^PHICH ) are used for the mapping of PHICHs to resource elements. A PHICH Enhanced Resource-element group is represented by the index pair (k', / ') of the resource element with the lowest index k in the group with all resource elements in the group having the same value of 1. The set of resource elements (k, /) in a PHICH enhanced resource-element group (eREG ^PHICH ) depends on whether the selected PHICH resource contains CRS or not as described below by k ₀ = n _PRB · , 0 < « _PRB < . - In the OFDM symbol / selected for a PHICH resource having NO cell-specific reference signals configured, the three PHICH enhanced resource-element groups in physical resource block np B include resource elements (k, I) with k = k ₀ + 0, ko + 1 , ... , k ₀ + 3, k = k ₀ + 4, k ₀ + 5, ... , k ₀ + 7, and k = ko + 8, k ₀ + 9, ... , k ₀ + 11 , respectively. In reference to Fig. 11 , the above description is exemplary illustrated as enhanced resource-element groups 303, 304 and 305 respectively in structure 300(a).

In the OFDM symbol / selected for a PHICH resource having cell-specific reference signals configured, the two PHICH enhanced resource-element groups in physical resource block npRB include resource elements (k, /) with k = k ₀ + 0, ko + 1 , ... , k ₀ + 5 and k = ko + 6, k ₀ + 7, ... , k ₀ + 11, respectively. In reference to Fig. 1 1 , the above description is exemplarily illustrated as enhanced resource-element groups 306, and 307 respectively in structure 300(b).

[0065]

(Step 3 - a PHICH group to eREG ^PH1CH mapping)

There are 2 options for a PHICH group to eREG ^PHICH mapping and a terminal can be informed by a base station via RRC signalling as to what option has been configured. The 2 mapping options are disclosed as follows:

a. A PHICH group to eREG ^PHlCH mapping for localized transmission.

For a localized transmission of a PHICH group, all three eREGs ^PHlCH of a PHICH group are located on the same PRB pair. PHICH symbol quadruplet with index i ( i = 0, 1, 2) for an antenna port p of a PHICH group are mapped on eREGs first in frequency and then in time. This is exemplarily illustrated in Fig. 12, with eREGs ^PHICH 401, 402 and 403 in structure 400(a) or 400(b) selected for the PHICH symbol quadruplet with index i ( i = 0, 1 , 2) mapping.

b. a PHICH group to eREG ^PHICH mapping for a distributed transmission: For a distributed transmission with the number of PRB pairs forming or being reserved for a 2nd control region ( N™ ), 3 eREGs ^PHICH of a PHICH group can be distributed on different PRB pairs. There may be more than 1 PHICH group being mapped on the same "2nd control region" (24) and maximum separation among PHICH groups' eREGs ^PHICH can be ensured. The method for achieving this requirement is disclosed in the following steps with the assisting example illustrated in Fig. 13A and 13B:

i. Let N _P ² _R ^R be the number of PRB pairs in a "2nd control region" (24) or "2nd control regions" that a group(s) of PHICH is configured to be mapped on

(In reference to example structure 500(a) in Fig. 13 A, N _P ² _p ^R = 4 )

ii. Let G™™ be the number of PHICH group(s) to be mapped on the OFDM symbol / being selected for PHICH resource (301), indexing eREG ^PHICH as

e = [0, l, 2, ... te ^cw - l)]

where N%™ = 3 x + 2 x Ν^ _∞) and [G ^PH!CHgroup = 0,1,2...50 ] with g being the group index

(In reference to example structure 500(a) in Fig. 13 A,

N _e REG ⁼ 3 ^x ^ PRB{no_ CRS) + 0 * N PRB(CRS) = 3 x 4 = 12 )

iii. Mapping the 1 st PHICH symbol quadruplet (i = 0) of the 1 st PHICH Group (g = 0) on the 1 st eREG ^PHICH index (e = 0)

(In reference to example structure 500(a) in Fig. 13 A, 1st eREG ^PH1CH index (g = 0, e = 0) is represented as 501 )

iv. Mapping the remaining PHICH symbol quadruplets ( i = 1 and 2) of the 1st PHICH Group (g = 0) on the eREG ^PHICH with an index equal to (1st eREG ^PH1CH index +

is the GAP between 2 consecutive eREGs ^PHICH in the same group and in a number of eREG ^PHICH

(In reference to exemplary structure 500(a) in Fig. 13 A, by following "iv", the GAP

12

between 2 consecutive eREGs ^PHICH is GAP™™ = 4 (504), and 2nd PHICH symbol

3

PHICH

quadruplet (i = 1, g = 0) (502) is mapped on eREGs index (e = 0 + 1 x 4 = 4) and the 3rd symbol quadruplet (i = 2, g = 0) (503) is mapped on eREGs ^PHICH index (e = 0 + 2 x 4 = v. Mapping the 1 st PHICH symbol quadruplet (i = 0) of the subsequence PHICH

GAP PHICH

Group with (g is not equal to 0) on the eREG index e = g x eREGs

PHICH

1 group

In reference to example structure 500(a) in Fig. 13 A, the number of PHICH groups is

-> PHICH

1 group = 2 , and the 1st PHICH symbol quadruplet (i = 0, g = 1) of the PHICH Group with (g =

GAR PHICH

1) (506) is mapped on the eREG™' ^LH index e = eREGs

-■PHICH = l x = 2 (505)

Tgroup

vi. Repeat step "iv" for the mapping of the remaining PHICH symbol quadruplets (i = 1 and 2) of the group (g is not equal to 0).

In reference to example structure 500(a) in Fig. 13 A, the 2nd PHICH symbol quadruplet

(i = 1, g = 1) (507) is mapped on eREGs ^PHICH index (e = 2 + 1 x 4 = 6) and the 3rd PHICH symbol quadruplet (i = 2, g = 1) (508) is mapped on eREGs ^PH1CH index (e = 2 + 2 x 4 = 10).

[0066]

By applying the method described in steps (i) to step (vi) above, a PHICH group to

PHICH

eREG mapping for a distributed transmission is further illustrated for variation of a number of PRB pairs, with or without CRS, reserved for the 2nd control region (24), and the number of PHICH groups as described below:

In reference to Fig. 14, mapping structure (510), on PRB pairs without CRS, for

(4 PRB pairs, 1 or 2 PHICH groups) => mapping 51 1 ;

- (6 PRB pairs, 1 or 2 PHICH groups) => mapping 512;

(6 PRB pairs, 3 PHICH groups) => mapping 513;

(8 PRB pairs, 1 or 2 PHICH groups) => mapping 514;

(8 PRB pairs, 3 PHICH groups) => mapping 515 ; and

(8 PRB pairs, 4 PHICH groups) => mapping 516; with 517a shows 3 PHICH eREGs of the 1st group (g = 0); 517b shows 3 PHICH eREGs of the 2nd group (g = 1); 517c shows 3 PHICH eREGs of the 3rd group (g = 2) and 517d shows 3 PHICH eREGs of the 4th group (g = 3).

In reference to Fig. 15, mapping structure (520), on PRB pairs with CRS, for

(4 PRB pairs, 1 or 2 PHICH groups) => mapping 521 ;

~ (6 PRB pairs, 1 or 2 PHICH groups) => mapping 522;

(6 PRB pairs, 3 PHICH groups) => mapping 523; (8 PRB pairs, 1 or 2 PHICH groups) => mapping 524;

(8 PRB pairs, 1 , 2 or 3 PHICH groups) => mapping 525; and

(8 PRB pairs, 4 PHICH groups) => mapping 526; with 527a shows 3 PHICH eREGs of the 1st group (g = 0); 527b shows 3 PHICH eREGs of the 2nd group (g = 1); 527c shows 3 PHICH eREGs of the 3rd group (g = 2) and 527d shows 3 PHICH eREGs of the 4th group (g = 3).

In reference to Fig. 16, mapping structure (530), on mixed PRB pairs with cell-specific reference signal (CRS) and without CRS, for

(8 PRB pairs with the 1 st 6 PRB pairs having CRS and the 7th and 8th PRB pairs having no CRS, 1 or 2 PHICH groups) => mapping 531 ;

(8 PRB pairs with the 1 st 6 PRB pairs having CRS and the 7th and 8th PRB pairs having no CRS, 1 , 2 or 3 PHICH groups) => mapping 532;

(8 PRB pairs with the 1 st 6 PRB pairs having CRS and the 7th and 8th PRB pairs having no CRS, 4 PHICH groups) => mapping 533; with 534 showing the PRB pairs without CRS and 535 showing the PRB pairs with CRS forming a PHICH resource.

[0067]

The PHICH eREGs in the PHICH resource, that is not selected for the mapping of a PHICH group in this step shall be used for Enhanced Physical Downlink Control Channel (EPDCCH) resource element (RE) mapping.

[0068]

(Step 4 - PHICH symbols of a PHICH quadruplet to RE(s) of a eREG ^PHICH mapping) It is understood that a PHICH symbol quadruplet z ^(p) (i) with (i = 0, 1 , 2) includes 4 I/Q symbols y ^(p) such as _z ^{p) (j) =

[0069]

For a eREG ^PHICH on PHICH resource ( / ) having NO cell-specific reference signals configured as illustrated in structure 300(a) of Fig. 1 1 , the set of 4 I/Q symbols 2), ^(p) (i + 3)) ^{m a} symbol quadruplet are mapped to resource elements (k,

I) with k = ke + 0, ke + 1 , ... , ke + 3 respectively, where ke is the frequency domain index of the 1 st RE in the eREG with index (e) predetermined in step 3 above.

[0070]

For a eREG ^PHICH on PHICH resource ( / ) having cell-specific reference signals (CRS) configured as illustrated in structure 300(b) of Fig. 1 1, and it is understood that on NCT, CRS is reduced to only port 0 (i.e. R0), the mapping of the set of 4 I/Q symbols (' ⁺ 2 ^' ),y ^<p) (i + 3†j

to resource elements (k, /) in the eREG ^PHICH with index (e) can be performed using one of the methods below for handling the collision of PHICH REs with CRS and to maximize the consecutive location of PHICH REs in an enhanced resource element group (eREG ^PHICH ):

I. Method 1 : assuming that 2 ports CRS are configured, mapping 4 I/Q symbols + l),y ^(p) (i + 2),y ^iP) (i + 3)) to remaining REs that are not occupied by CRS

REs in the eREG with an index (e) predetermined in step 3. This is the same as prior art legacy LTE and this is exemplarily illustrated in Fig. 17 (such as a structure 600).

II. Method 2: this method aims to provide consecutive mapping of 4 I/Q symbols + [),y ⁽ - ⁾ (i + 2),y ⁽ - ^p) (i + 3))

in a symbol quadruplet z ^(p) (i) to utilize the flat channel for better performance.

The set of 4 I/Q symbols y ^p i),y ^(p) (i + lXy ^(p) (i + 2),y ^{p) (i + 3y^ are mapped to resource elements (k,

[) with the 1st I/Q symbol y ^ip) (i) being mapped on RE (k, Γ) with a frequency domain index stating with k = ke + k', and the I/Q symbols (y ⁽ - ^p) (i + \),y ^{p) (i + 2), y ^iP) (i + 3)) are mapped to resource elements (k, ) immediately follow starting RE that is not occupied by CRS.

where

ke is the frequency domain index of the 1st RE in the eREG ^PHICH with an index (e) predetermined in step 3, and k> _ { (( ^{v + N} ?D ) ^{mod 6 + l} ) ^{mod 3} f ^or (( ^{v + N} ID )m°d 3

~ l((v + N? _D " )mod 6 + 2)mod 3 otherwise v = 0 or 3

By applying method 2, the mapping of 4 I/Q symbols

(i + 2),y ^{{ )} (i + 3))

are mapped to resource elements (k, /) within the eREG with index (e) illustrated in Fig. 18 (such as a structure 600a - 600f) for all possible offset values due to a Cell ID number (N ") and OFDM symbol ( / ) having CRS.

[0071]

THIRD ASPECT OF EMBODIMENT

The 3rd aspect of this embodiment is a system and method for physical channels transmission and reception on the NCT carrier with the subframe structure in the 1 st aspect of the present embodiment.

[0072]

In reference to Fig. 6, a communication system (100) is exemplarily illustrated. The communication system (100) includes:

a base station/eNodeB (101) supporting legacy LTE carrier (103),

a base station/eNodeB (101 bis) supporting NCT carrier (103bis) and

Terminal/User equipment (UE) (102).

[0073]

the base station/eNodeB (101) and the base station/eNodeB (101 bis) may be collocated or geographically separated.

[0074]

The legacy LTE carrier (103) has both a Downlink Carrier component and an Uplink Carrier component.

[0075]

The NCT carrier (103bis) may be configured to have only a Downlink Carrier component (103a), or have both the Downlink Carrier component (103a) and an Uplink Carrier component (103b). The Downlink Carrier component (103a) may include a PBCH (104), a EPDCCH (105), a DMRS (106), a PDSCH (107), a PHICH (108), a CRS (108a), a CSI-RS (110), and a Synchronization signaling (111). The Uplink Carrier component (103b) may include a PUSCH (109), and a PUCCH (112).

[0076]

The terminal (102) supports both the legacy LTE carrier (103) and NCT carrier (103bis).

[0077]

(Case 1)

In the case that the NCT carrier (103bis) provided by the base station (101 bis), is used in conjunction with carrier aggregation of the legacy LTE carrier (103) being provided by the base station (101), the UE (102) establishes Radio Resource Control (RRC) connection through the legacy LTE carrier (103). By RRC-signalling on the legacy carrier (103), the UE (102) can be configured to operate on the NCT carrier (103bis) for the reception of a physical downlink shared channel (PDSCH) (107).

[0078]

If "cross carrier scheduling" is set to "enable", the UE (102) receives the Downlink scheduling assignments transmitted by the base station (101) on physical downlink control channel (PDCCH) or enhanced (E)-PDCCH of the legacy LTE carrier (103). The mentioned Downlink scheduling assignments include information required for the UE (102) to be able to properly receive, demodulate, and decode the DL-SCH/PDSCH (107) on the aggregated NCT DL carrier component (103a). [0079]

If "cross carrier scheduling" is set to "disable", the UE (102) can via the legacy LTE carrier (103) receive the RRC-signalling on the configuration of the "2nd control region" (24 in the structure 20 in Fig. 5). With the provided "2nd control region" configuration on the NTC DL carrier component (103a), the base station (l Olbis) can transmit associated EPDCCHs (105) on the configured "2nd control region" and the UE (102) can monitor the associated EPDCCHs (105) on the configured "2nd control region" for its downlink scheduling assignments. The mentioned Downlink scheduling assignments includes information required for the UE to be able to properly receive, demodulate, and decode the DL-SCH/PDSCH (107) on the aggregated NCT DL carrier component (103a).

[0080]

For both cases of "cross carrier scheduling" being enable and disable, the UE can transmit Hybrid-A Q acknowledgements in response to DL-SCH reception on the NCT DL carrier (103a) and CSI feedback information measured on a CSI-RS (110) to the base station (101) via physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) scheduled on the legacy LTE carrier (103).

[0081]

(Case 2)

In the case that the NCT carrier (103 bis) provided by the base station (101 bis), is used in conjunction with carrier aggregation of the legacy LTE carrier (103) provided by the base station (101), the UE (102) establishes RRC-connection through the legacy LTE carrier (103).

By RRC-signalling on legacy carrier, UE can be configured to operate on the NCT carrier

(103bis) for the reception of the DL-SCH/PDSCH (107) and the transmission of a

UL-SCH/PUSCH (109).

[0082]

If "cross carrier scheduling" is set to "enable", the UE ( 102) can receive the Downlink scheduling assignments and/or UL grant transmitted by the base station (101) on PDCCH or EPDCCH of the legacy LTE carrier (103). The mentioned Downlink scheduling assignments include information required for the UE to be able to properly receive, demodulate, and decode the DL-SCH/PDSCH (107) on the aggregated NCT DL carrier component (103a). The mentioned Uplink Grant includes information required for the UE to be able to properly encode, modulate and transmit the UL-SCH/PUSCH (109) on the aggregated NCT UL carrier component ( 103b). Additionally, upon the reception of the UL-SCH on the aggregated NCT UL carrier component (103b), the base station (101 bis) can configure for the transmission of a H-ARQ acknowledgement on the legacy PHICH of the LTE carrier component (103). On a predetermined DL subframe, the UE (102) can also monitor PHICH on the legacy LTE carrier (103) for the Hybrid- ARQ acknowledgements in response to UL-SCH/PUSCH transmission on its NCT uplink (UL) carrier component. Furthermore, the UE can provide Hybrid- ARQ acknowledgements in response to DL-SCH reception on the NCT carrier component (103a) and CSI feedback information measured on CSI-RS (110) to the base station (101 ) via PUCCH scheduled on the legacy LTE carrier if there is no PUSCH scheduled for transmission at the instant when H-ARQ acknowledgements and/or CSI feedback are/is scheduled to be transmitted. Otherwise, the UE can provide Hybrid-ARQ acknowledgements in response to DL-SCH reception on the NCT carrier component (103a) and CSI feedback information measured on the CSI-RS (110) to the base station (lOlbis) via the PUSCH (109) scheduled on the NCT carrier if there is PUSCH scheduled for transmission on the NCT Uplink carrier component (103b).

[0083]

If "cross carrier scheduling" is set to "disable", the UE (102) can via the legacy LTE carrier (103) receive the RRC-signalling on the configuration of the "2nd control region" (24 in the structure 20 in Fig. 5). With the provided "2nd control region" (24) configuration on the NCT carrier (103bis), the base station (lOlbis) can transmit the EPDCCHs (105) on the configured "2nd control region" (24) providing downlink scheduling assignments and/or Uplink Grant to the UE (102). Additionally, the base station (lOlbis) can also configure PHICH resources (27 in the structure 20 in Fig. 5) for the transmission of the PHICH (108) carrying the Hybrid-ARQ acknowledgements in response to UL-SCH/PUSCH reception on the NCT UL carrier component (103b). The UE (102) can monitor the configured "2nd control region" (24) for its downlink scheduling assignments and/or Uplink Grant. The mentioned Downlink scheduling assignments include information required for the UE to be able to properly receive, demodulate, and decode the DL-SCH/PDSCH (107) on the aggregated NCT DL carrier component (103 a). The mentioned Uplink Grant includes information required for the UE to be able to properly encode, modulate and transmit the UL-SCH/PUSCH (109) on the aggregated NCT UL carrier component (103b). Additionally, the base station (lOlbis) can transmit the PHICH (108) carrying UL Hybrid-ARQ acknowledgements, within the allocated PHICH resource (27), and UE (102) can monitor the configured PHICH resource (27) for the response to its UL-SCH/PUSCH transmission on the NCT UL carrier component (103b) in the previous UL subframe. Furthermore, the UE can provide Hybrid-ARQ acknowledgements in response to DL-SCH reception on the NCT carrier component (103a) and CSI feedback information measured on the CSI-RS (110) to the base station (101) via the PUCCH (112) or the PUSCH (109) on the NCT UL carrier component (103b).

[0084]

(Case 3)

In the case that the new carrier type (103bis) provided by the base station (101 bis) is configured to operate in a standalone mode (i.e. no carrier aggregation with a legacy LTE carrier), the base station (lOlbis) can configure the downlink (DL) carrier component (103a) according to the following procedures:

a. A procedure for system information acquisition and connection establishment on the NCT component carrier (103 bis) will now be described below.

Base station ( 101 bis) can configure

i. The "1st control region" (23) for the transmission of EPDCCH(s) forming common search spaces,

ii. The "1 st control region" (23) size in number of PRB pair(s) according to an amount of common information that needs to address a group of, or all, terminals in the coverage area. This includes the dynamic scheduling of system information, transmission of paging messages, transmission of explicit power-control commands, etc.

iii. The "1 st control region" (23) PRB pairs' location for predetermined localized transmission and/or a distributed transmission that is appropriate to an interference mitigation/coordination strategy.

iv. An orthogonal "short code" that is code-multiplexed with a part of the reference signal sequence on a PRB basis to assist a terminal in blind detection of PRB pair(s) allocated for a 1 st control region(s),

At a terminal UE (102) that is capable to operate on a NCT.

v. At power up, a terminal can perform a cell-search procedure to find and acquire synchronization with the base station (l Olbis). Once the terminal (102) has achieved the cell-search procedure, it may acquire the cell system information, corresponding to Master Information Block (MIB). This information can assist a terminal to regenerate the "short code" sequence replica on a subframe basis and on a PRB pair basis.

vi. Once the terminal (102) has achieved the MIB, it may, on a subframe on the NCT DL carrier component, attempt to detect (a) PRB pair(s) that is/are allocated to the

"1 st control region(s)" (23). Upon the successful identification of PRB pairs carrying the "1 st control region" (23), the UE (102) can monitor control channel elements (CCEs) in the common search spaces for control information on the dynamic scheduling of system information.

vii. A UE (102) is in RRC IDLE mode, when it wakes up at predefined time interval to monitor paging information transmitted from the base station (10 Ibis); it should first attempt to detect (a) PRB pair(s) that is/are allocated to the "1st control region(s)". Upon the successful identification of (a) PRB pair(s) carrying "1st control region", the UE (102) should monitor CCEs in the common search spaces for control information on the transmission of a paging messages.

viii. A UE ( 102) is in RRC_IDLE mode, when it wakes up to initiate connection set up with the base station (101 bis). In the 1st step it transmits a random access preamble on the NTC UL carrier component (103 b). In response to the detected random access attempt, the base station (101 bis) can transmit a random access response message on the

DL-SCH with the associated control information being sent oh associated EPDCCHs mapping in the common search spaces in the "1 st control region" (23). In the second step, the UE (102) can at a predetermined DL subframe, attempt to detect (a) PRB pair(s) that is/are allocated to the "1st control region(s)" (23). Upon the successful identification of (a) PRB pair(s) carrying the "1st control region" (23), the UE (102) can monitor CCEs in the common search spaces for control information on the transmission of random access response messages.

The base station (lOlbis) may configure one or several "1st control region" (23) on a subframe. The base station (101 bis) may continue to utilize common search spaces in the "1st control region" to provide control signalling in establishing RRC-connection with the UE (102) for RRC-signalling transmission on DL-SCH/PDSCH.

b. A procedure for DL-SCH/PDSCH and/or UL-SCH/PUSCH transmission and reception on the NCT component carrier (103bis) in RRC_CONNECTED mode will now be described below.

In RRC CONNECTED mode, the UE (102) can via the RRC-signalling receive the configuration of a "2nd control region" (24 in the structure 20 in Fig. 5). With the provided "2nd control region" (24) configuration on the NTC (103bis), the base station (lOlbis) can transmit the EPDCCHs (105) on the configured "2nd control region" (24) providing downlink scheduling assignments and/or Uplink Grant to the UE (102). Additionally, the base station (lOlbis) can also configure PHICH resources (27 in the structure 20 in Fig. 5) for the

transmission of the PHICH (108) carrying the Hybrid- ARQ acknowledgements in response to UL-SCH/PUSCH reception on the NCT UL carrier component (103b). The UE (102) can monitor the configured "2nd control region" (24) for its downlink scheduling assignments and/or Uplink Grant. The mentioned Downlink scheduling assignments include information required for the UE (102) to be able to properly receive, demodulate, and decode the DL-SCH/PDSCH (107) on the aggregated NCT DL carrier component (103a). The mentioned Uplink Grant includes information required for the UE (102) to be able to properly encode, modulate and transmit the UL-SCH/PUSCH (109) on the aggregated NCT UL carrier component (103b). Additionally, the base station (101 bis) can transmit the PHICH (108) carrying UL Hybrid- ARQ acknowledgements, within the allocated PHICH resource (27), and the UE (102) can monitor the configured PHICH resource (27) for the response to its UL-SCH/PUSCH transmission on the NCT UL carrier component (103b) in the previous UL subframe. Furthermore, the UE should can Hybrid- ARQ acknowledgements in response to DL-SCH reception on the NCT carrier component (103a) and CSI feedback information measured on the CSI-RS (110) to base station (101) via the PUCCH (112) or the PUSCH (109) on the NCT UL carrier component (103b).

[0085]

A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

[0086]

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

[0087]

This software can be stored in various types of non-transitory computer readable media arid thereby supplied to computers. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include a magnetic recording medium (such as a flexible disk, a magnetic tape, and a hard disk drive), a magneto-optic recording medium (such as a magneto-optic disk), a CD-ROM (Read Only Memory), a CD-R, and a CD-R/W, and a semiconductor memory (such as a mask ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), a flash ROM, and a RAM (Random Access Memory)). Further, the program can be supplied to computers by using various types of transitory computer readable media. Examples of the transitory computer readable media include an electrical signal, an optical signal, and an electromagnetic wave. The transitory computer readable media can be used to supply programs to computer through a wire communication path such as an electrical wire and an optical fiber, or wireless

communication path.

[0088] This application is based upon and claims the benefit of priority from Australian Provisional Patent Application No. 2013900069, filed on January 9, 2013, the disclosure of which is incorporated herein in its entirety by reference. Reference Signs List

[0089]

Fl legacy Long Term Evolution (LTE) carrier

F2 New Carrier Type (NCT) carrier

la, lb, 2a, 2b, 2c scenario

10a, 10b structure

11a, l ib control region

12a, 12b data region

20 structure

21 Downlink Bandwidth configuration

22 slots

23 1st control region

24 2nd control region

25 data region

26 Short code

27 PHICH resources

100 communication system

101 base station/eNodeB

lOlbis base station/eNodeB

102 Terminal/User equipment (UE)

103 legacy LTE carrier

103a Downlink Carrier component

103b Uplink Carrier component

103bis NCT carrier

104 PBCH

105 EPDCCH

106 DMRS

107 DL-SCH/PDSCH

108 PHICH

108a CRS 109 UL-SCH/PUSCH

110 CSI-RS

111 Synchronization signaling

112 PUCCH

200a, 200b, 200c normal CP NCT subframe

201 Mapping to REs

202 PHICH

203 PHICH

204 PHICH

205 PRBs

206 PRBs

207 PRBs

208 1 st Demodulation Reference Signal (DMRS)

209 CSI-RS

210 PHICH resource

211 CRS-RE

250a structure

250b structure

251 subcarries

252 DMRS

253 CSI-RS

254 PHICH resources

255 CRS

300a, 300b structure

301 , 302 PHICH resource

303 - 307 enhanced resource-element group

400a, 400b structure

401 - 403 eREGs ^PHICH

500a, 500b structure

501 -504, 504a, 505 - 508 eREGs ^PHICH

510 mapping structure

511 - 516 mapping

517a - 517d PHICH eREGs

520 structure 521 - 526 mapping 527a - 512d PHICH eREGs

530 mapping structure

531 - 533 mapping

534 PRB pairs

535 PRB pairs

600 structure

600a - 600f structure