US20140204868A1

US20140204868A1 - Method and apparatus for improving a new carrier type in a wireless communication system

Info

Publication number: US20140204868A1
Application number: US14/160,915
Authority: US
Inventors: Ko-Chiang Lin
Original assignee: Innovative Sonic Corp
Current assignee: Innovative Sonic Corp
Priority date: 2013-01-22
Filing date: 2014-01-22
Publication date: 2014-07-24
Also published as: TWI524788B; US20140204869A1; CN103944669B; TW201434301A; TWI561037B; ES2874490T3; EP2757733B1; EP2757733A2; EP2757733A3; KR20140094474A; TW201433187A; JP2014143685A; US10091772B2; CN103944669A; KR101587511B1; JP5722471B2

Abstract

Methods and apparatuses are disclosed to improve a new carrier type in a wireless communication system. The method includes having, in at least one subframe, more than one number of available resource elements among Physical Resource Blocks (PRBs) in a cell. The method further includes receiving an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same number of available resource elements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/755,150 filed on Jan. 22, 2013, the entire disclosure of which is incorporated herein by reference.

FIELD

This disclosure generally relates to wireless communication networks, and more particularly, to methods and apparatuses for improving a new carrier type in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of data to and from mobile communication devices, traditional mobile voice communication networks are evolving into networks that communicate with Internet Protocol (IP) data packets. Such IP data packet communication can provide users of mobile communication devices with voice over IP, multimedia, multicast and on-demand communication services.
An exemplary network structure for which standardization is currently taking place is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can provide high data throughput in order to realize the above-noted voice over IP and multimedia services. The E-UTRAN system's standardization work is currently being performed by the 3GPP standards organization. Accordingly, changes to the current body of 3GPP standard are currently being submitted and considered to evolve and finalize the 3GPP standard.

SUMMARY

Methods and apparatuses are disclosed to improve a new carrier type in a wireless communication system. One method includes having, in at least one subframe, more than one number of available resource elements among Physical Resource Block (PRB) pairs in a cell. The method further includes receiving an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same number of available resource elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according to one exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as access network) and a receiver system (also known as user equipment or UE) according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system according to one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3 according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband), WiMax, or some other modulation techniques.
In particular, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including Document Nos. R1-124776, “On New Carrier Type”, RP-121415, “New WI proposal: New Carrier Type for LTE”, TS 36.211 V11.1.0, “E-UTRA Physical channels and modulation”, TS 36.213 V11.1.0, “E-UTRA Physical layer procedures”, R1-124717, “On collision between DM RS and PSS/SSS in new carrier”. The standards and documents listed above are hereby expressly incorporated by reference in their entirety.
FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention. An access network 100 (AN) includes multiple antenna groups, one including 104 and 106, another including 108 and 110, and an additional including 112 and 114. In FIG. 1, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal 116 (AT) is in communication with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 over forward link 120 and receive information from access terminal 116 over reverse link 118. Access terminal (AT) 122 is in communication with antennas 106 and 108, where antennas 106 and 108 transmit information to access terminal (AT) 122 over forward link 126 and receive information from access terminal (AT) 122 over reverse link 124. In a FDD system, communication links 118, 120, 124 and 126 may use different frequency for communication. For example, forward link 120 may use a different frequency then that used by reverse link 118.
Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access network. In the embodiment, antenna groups each are designed to communicate to access terminals in a sector of the areas covered by access network 100.
In communication over forward links 120 and 126, the transmitting antennas of access network 100 may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals 116 and 122. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to all its access terminals.
An access network (AN) may be a fixed station or base station used for communicating with the terminals and may also be referred to as an access point, a Node B, a base station, an enhanced base station, an eNB, or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.
FIG. 2 is a simplified block diagram of an embodiment of a transmitter system 210 (also known as the access network) and a receiver system 250 (also known as access terminal (AT) or user equipment (UE)) in a MIMO system 200. At the transmitter system 210, traffic data for a number of data streams is provided from a data source 212 to a transmit (TX) data processor 214.
In one embodiment, each data stream is transmitted over a respective transmit antenna. TX data processor 214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.
The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor 230.
The modulation symbols for all data streams are then provided to a TX MIMO processor 220, which may further process the modulation symbols (e.g., for OFDM). TX MIMO processor 220 then provides N_Tmodulation symbol streams to N_Ttransmitters (TMTR) 222 a through 222 t. In certain embodiments, TX MIMO processor 220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.
Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. N_Tmodulated signals from transmitters 222 a through 222 t are then transmitted from N_Tantennas 224 a through 224 t, respectively.
At receiver system 250, the transmitted modulated signals are received by N_Rantennas 252 a through 252 r and the received signal from each antenna 252 is provided to a respective receiver (RCVR) 254 a through 254 r. Each receiver 254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.
An RX data processor 260 then receives and processes the N_Rreceived symbol streams from N_Rreceivers 254 based on a particular receiver processing technique to provide N_T“detected” symbol streams. The RX data processor 260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor 260 is complementary to that performed by TX MIMO processor 220 and TX data processor 214 at transmitter system 210.
A processor 270 periodically determines which pre-coding matrix to use (discussed below). Processor 270 formulates a reverse link message comprising a matrix index portion and a rank value portion.
The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 238, which also receives traffic data for a number of data streams from a data source 236, modulated by a modulator 280, conditioned by transmitters 254 a through 254 r, and transmitted back to transmitter system 210.
At transmitter system 210, the modulated signals from receiver system 250 are received by antennas 224, conditioned by receivers 222, demodulated by a demodulator 240, and processed by a RX data processor 242 to extract the reserve link message transmitted by the receiver system 250. Processor 230 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.
Turning to FIG. 3, this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the invention. As shown in FIG. 3, the communication device 300 in a wireless communication system can be utilized for realizing the UEs (or ATs) 116 and 122 in FIG. 1, and the wireless communications system is preferably the LTE system. The communication device 300 may include an input device 302, an output device 304, a control circuit 306, a central processing unit (CPU) 308, a memory 310, a program code 312, and a transceiver 314. The control circuit 306 executes the program code 312 in the memory 310 through the CPU 308, thereby controlling an operation of the communications device 300. The communications device 300 can receive signals input by a user through the input device 302, such as a keyboard or keypad, and can output images and sounds through the output device 304, such as a monitor or speakers. The transceiver 314 is used to receive and transmit wireless signals, delivering received signals to the control circuit 306, and outputting signals generated by the control circuit 306 wirelessly.
FIG. 4 is a simplified block diagram of the program code 312 shown in FIG. 3 in accordance with one embodiment of the invention. In this embodiment, the program code 312 includes an application layer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and is coupled to a Layer 1 portion 406. The Layer 3 portion 402 generally performs radio resource control. The Layer 2 portion 404 generally performs link control. The Layer 1 portion 406 generally performs physical connections.
For LTE or LTE-A systems, the Layer 2 portion may include a Radio Link Control (RLC) layer and a Medium Access Control (MAC) layer. The Layer 3 portion may include a Radio Resource Control (RRC) layer.
In 3GPP R1-124776, a new carrier type was introduced to reduce the signalling overhead and to increase spatial efficiency such that interference is reduced and energy cost is efficient. In 3GPP RP-121415 describes the new carrier type as follows:
In a first phase specify the New Carrier Type (NCT) being aggregated with a legacy LTE carrier.

- Specify necessary enhancements for transmission of data and control as well as the necessary UE mobility support on the New Carrier Type.
- Evaluate the benefits achievable from the standalone New Carrier Type over those achieved from legacy LTE and from the carrier aggregated New Carrier Type
- Identify the scenarios for the standalone New Carrier Type
  In a second phase specify enhancements to the New Carrier Type also considering the findings of the small cell related Rel-12 studies (from RAN#61)
- If justified by the evaluation, specify necessary means to allow standalone and macro-assisted operation on the New Carrier Type, including
  - A broadcast mechanism to acquire system information, a common search space for ePDCCH and UE mobility support.
  - If justified by the small cell related studies, specify necessary means to support a dual dormant/active state, which means DTX like eNB behaviour (with long DTX cycles) and corresponding UE procedures, with or without reduced CRS in the active state. Note that the dual dormant/active state can be specified for NCT aggregated with a legacy carrier and/or operating in a macro assisted mode even if the standalone carrier is not justified by the evaluation.
- Verify the suitability of the solutions specified in the first phase for the purposes of standalone New Carrier Type operations and small cells and update the necessary functionalities and signals if necessary.
- Specify corresponding UE and eNB core requirements
  Note that the work will proceed from the starting point of the agreements and working assumptions reached so far in RAN1 during the Rel-11 work item.
- Note that small cell related enhancements will include also non-NCT related solutions, which will be specified in other WIs.

In the above-discussed 3GPP documents, there were discussions about how many legacy signals can be removed from the New Carrier Type (NCT). As disclosed in 3GPP TS 36.211 V11.1.0, a signal such as Primary Synchronization Signal (PSS)/Secondary Synchronization Signal (SSS) is needed to guarantee the synchronization performance at least for the stand-alone case. In an unsynchronized, non-standalone case, the impact to the overhead reduction seems neutral as PSS/SSS is transmitted every 5 ms. As a result, 3GPP RAN1 concludes that it is possible to keep PSS/SSS transmission on the NCT.
In 3GPP TS 36.211 V11.1.0, it is assumed that the density of Cell-specific Reference Signal (CRS) will be reduced both in time domain and frequency domain as CRS accounts for a significant part of signalling overhead. Therefore, some of the transmission scheme disclosed in Rel-10 cannot be supported as their demodulation is based on CRS. Instead, the Demodulation Reference Signal (DMRS) introduced in Rel-10 will be considered as the basic demodulation reference. One potential issue of this design is DMRS and PSS/SSS could collide. In Rel-10, this issue is acknowledged and the proposed solution provides that those physical resource blocks (PRBs) containing PSS/SSS or Physical Broadcast Channel (PBCH) could be scheduled with for legacy transmission scheme (based on CRS). In such a situation, the user equipment (UE) would assume that there is no transmission based on DMRS (as disclosed in 3GPP TS 36.213 V11.1.0), which is not possible given that the CRS would be eliminated.
3GPP discloses that for a type 1 frame structure:

- the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 5 in any subframe in which the number of OFDM symbols for PDCCH with normal CP is equal to four;
  - the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 5, 7, 8, 9, 10, 11, 12, 13 or 14 in the two PRBs to which a pair of VRBs is mapped if either one of the two PRBs overlaps in frequency with a transmission of either PBCH or primary or secondary synchronisation signals in the same subframe;
- the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 7 for which distributed VRB resource allocation is assigned.
- The UE may skip decoding the transport block(s) if it does not receive all assigned PDSCH resource blocks. If the UE skips decoding, the physical layer indicates to higher layer that the transport block(s) are not successfully decoded.

3GPP discloses that for a type 2 frame structure:

- the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 5 in any subframe in which the number of OFDM symbols for PDCCH with normal CP is equal to four;
- the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 5 in the two PRBs to which a pair of VRBs is mapped if either one of the two PRBs overlaps in frequency with a transmission of PBCH in the same subframe;
- the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 7, 8, 9, 10, 11, 12, 13 or 14 in the two PRBs to which a pair of VRBs is mapped if either one of the two PRBs overlaps in frequency with a transmission of primary or secondary synchronisation signals in the same subframe;
- with normal CP configuration, the UE is not expected to receive PDSCH on antenna port 5 for which distributed VRB resource allocation is assigned in the special subframe with configuration #1 or #6;
- the UE is not expected to receive PDSCH on antenna port 7 for which distributed VRB resource allocation is assigned;
- with normal cyclic prefix, the UE is not expected to receive PDSCH resource blocks transmitted on antenna port 5 in DwPTS when the UE is configured with special subframe configuration 9.
- The UE may skip decoding the transport block(s) if it does not receive all assigned PDSCH resource blocks. If the UE skips decoding, the physical layer indicates to higher layer that the transport block(s) are not successfully decoded.

A UE is not expected to monitor an enhanced physical downlink control channel (EPDCCH) candidate, if an enhanced control channel element (ECCE) corresponding to that EPDCCH candidate is mapped to a physical resource block (PRB) pair that overlaps in frequency with a transmission of either Physical Broadcast Channel (PBCH) or primary or secondary synchronization signals in the same subframe.
Accordingly, in 3GPP R1-124717, RAN1 began considering several alternatives that were raised during Rel-11 discussions as follows:

- Alt 1: Avoid collisions between PSS/SSS and DM-RS by moving the PSS/SS
  - 1a: keeping Rel-8 relative locations of PSS/SSS
  - 1b: change relative locations of PSS/SSS
- Alt 2: Change the DM-RS pattern on NCT (i.e. in all subframes) to give better performance for PDSCH demodulation in the absence of a legacy control region (and thereby also avoiding collisions with PSS/SSS)
- Alt 3: Do nothing about PSS/SSS DM-RS collisions in Rel-11
  - 3a: Puncture DM-RS
  - 3b: Forbid PDSCH transmissions in PRBs with PSS/SSS

For Alt 1/Alt 2, a new signal design is needed, and it needs to be verified whether the new signaling could fulfill the requirement needs. Alt 3 seems most in-line with Rel-10 design, and Alt 3b would result in unused resources.
In 3GPP TS 36.213 V11.1.0, EPDCCH was introduced to improve the spectral efficiency and also the capacity of control channel. For a Physical Downlink Control Channel (PDCCH), there was a fix set of aggregation level {1,2,4,8}/blind decoding attempt split{6,6,2,2}. However, as the coverage of EPDCCH is expected to be smaller than PDCCH and in order to also efficiently utilize the blind decoding attempts, the aggregation level and blind decoding attempt distribution would depend on several attributes such as the number of available resource elements for EPDCCH and the payload size of EPDCCH. As disclosed in 3GPP TS 36.211 V.11.1.0, for example, the aggregation level set as follows (Note that as shown below different downlink control information (DCI) formats could be in different payload sizes and downlink bandwidth configuration (N_RB ^DL) is also an attribute to compute payload size):

- The enhanced physical downlink control channel (EPDCCH) carries scheduling assignments. An enhanced physical downlink control channel is transmitted using an aggregation of one or several consecutive enhanced control channel elements (ECCEs) where each ECCE consists of multiple enhanced resource element groups (EREGs), defined in Section 6.2.4A. The number of ECCEs used for one EPDCCH depends on the EPDCCH format as given by Table 6.8A.1-2 and the number of EREGs per ECCE is given by Table 6.8A.1-1. Both localized and distributed transmission is supported.
- An EPDCCH can use either localized or distributed transmission, differing in the mapping of ECCEs to EREGs and PRB pairs.
- A UE shall monitor multiple EPDCCHs as defined in 3GPP TS 36.213 V11.1.0. One or two sets of physical resource-block pairs which a UE shall monitor for EPDCCH transmissions can be configured. All EPDCCH candidates in EPDCCH set S_muse either only localized or only distributed transmission as configured by higher layers. Within EPDCCH set S_min subframe i, the ECCEs available for transmission of EPDCCHs are numbered from 0 to N_ECCE,m,i−1 and ECCE number n corresponds to
  - EREGs numbered (n mod N_RB ^ECCE)+jN_RB ^ECCEin PRB index └n/N_RB ^ECCE┘ for localized mapping, and
  - EREGs numbered └n/N_RB ^S ^m┘+jN_RB ^ECCEin PRB indices (n+j max (1, N_ECCE ^EREG))mod N_RB ^S ^mfor distributed mapping,
- where j=0, 1, . . . , N_ECCE ^EREG−1, N_ECCE ^EREGis the number of EREGs per ECCE, and N_RB ^ECCE=16/N_ECCE ^EREGthe number of ECCEs per resource-block pair. The physical resource-block pairs constituting EPDCCH set S_mare in this paragraph assumed to be numbered in ascending order from 0 to N_RB ^S ^m−1.

TABLE 6.8A.1-1

Number of EREGs per ECCE, N_ECCE ^EREG.

Normal cyclic prefix

Extended cyclic prefix

	Special	Special		Special
Normal	subframe,	subframe,	Normal	subframe,
sub-	configuration	configuration	sub-	configuration
frame
	3, 4, 8	1, 2, 6, 7, 9	frame	1, 2, 3, 5, 6

4	8

TABLE 6.8A.1-2

Supported EPDCCH formats.

Number of ECCEs for one EPDCCH, N_EPDCCH ^ECCE

Case 1 Case 2

EPDCCH Localized Distributed Localized Distributed

format transmission transmission transmission transmission

0 2 2 1 1

1 4 4 2 2

2 8 8 4 4

3 16 16 8 8

4 — 32 — 16

Case 1 in Table 6.8A.1-2 applies when

- DCI formats 2, 2A, 2B, 2C or 2D is used and N_RB ^DL≧25, or
- any DCI format when n_EPDCCH<104 and normal cyclic prefix is used in normal subframes or special subframes with configuration 3, 4, 8.
  Otherwise, case 2 is used. The quantity n_EPDCCHfor a particular UE is defined as the number of downlink resource elements (k, l) in a physical resource-block pair configured for possible EPDCCH transmission of EPDCCH set S₀and fulfilling all of the following criteria:
- they are part of any one of the 16 EREGs in the physical resource-block pair, and
- they are assumed by the UE not to be used for cell-specific reference signals or CSI reference signals as given by Section 7.1.9 of 3GPP TS 36.213 V11.1.0, and
- the index l in the first slot in a subframe fulfils l≧l_EPDCCHStartwhere l_EPDCCHStartis given by Section 9.1.4.1 of 3GPP TS 36.213 V11.1.0.

Similarly, the EPDCCH blind decoding attempt distribution would have something to do with the number of available resource elements for EPDCCH and the payload size of EPDCCH as discussed in 3GPP TS 36.213 V11.1.0.

- For Tables 9.1.4-1a, 9.1.4-1b, 9.1.4-2a, 9.1.4-2b, 9.1.4-3a, 9.1.4-3b, 9.1.4-4a, 9.4.4-4b, 9.1.4-5a, 9.1.4-5b
  - Case 1 applies
    - when DCI formats 2/2A/2B/2C/2D are monitored and N_RB ^DL≧25, or
    - for normal subframes and normal downlink CP when DCI formats 1A/1B/1D/1/2/2A/2B/2C/2D/0/4 are monitored, and when n_EPDCCH<104 (n_EPDCCHdefined in section 6.8A.1 of 3GPP TS 36.211 V11.1.0), or
    - for special subframes with special subframe configuration 3, 4, 8 and normal downlink CP when DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored;
  - Case 2 applies
    - for normal subframes and extended downlink CP when DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored or,
    - for special subframes with special subframe configuration 1,2,6,7,9 and normal downlink CP when DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored, or
    - for special subframes with special subframe configuration 1,2,3,5,6 and extended downlink CP when DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored;
  - otherwise
    - Case 3 is applied.
      N_RB ^X ^p(defined in section 6.8A.1 of 3GPP TS 36.211 V11.1.0) is the number of PRB-pairs constituting EPDCCH-PRB-set p

TABLE 9.1.4-1a

EPDCCH candidates monitored by a UE
(One Distributed EPDCCH-PRB-set - Case 1, Case 2)

	Number of PDCCH candidates	Number of PDCCH candidates
	M_p ^(L)for Case 1	M_p ^(L)for Case 2

N_RB ^X _p	L = 2	L = 4	L = 8	L = 16	L = 32	L = 1	L = 2	L = 4	L = 8	L = 16

2	[4]	[2]	[1]	[0]	[0]	[4]	[2]	[1]	[0]	[0]
4	[8]	[4]	[2]	[1]	[0]	[8]	[4]	[2]	[1]	[0]
8	[6]	[4]	[3]	[2]	[1]	[6]	[4]	[3]	[2]	[1]

TABLE 9.1.4-1b

EPDCCH candidates monitored by a UE (One
Distributed EPDCCH-PRB-set - Case 3)

Number of PDCCH candidates M_p ^(L)for Case 3

N_RB ^X ^p	L = 1	L = 2	L = 4	L = 8	L = 16

2	[8]	[4]	[2]	[1]	[0]
4	[4]	[5]	[4]	[2]	[1]
8	[4]	[4]	[4]	[2]	[2]

TABLE 9.1.4-2a

EPDCCH candidates monitored by a UE
(One Localised EPDCCH-PRB-set - Case 1, Case 2)

	Number of PDCCH	Number of PDCCH
	candidates M_p ^(L)for	candidates M_p ^(L)for
	Case 1	Case 2

N_RB ^X _p	L = 2	L = 4	L = 8	L = 16	L = 1	L = 2	L = 4	L = 8

2	[4]	[2]	[1]	[0]	[4]	[2]	[1]	[0]
4	[8]	[4]	[2]	[1]	[8]	[4]	[2]	[1]
8	[6]	[6]	[2]	[2]	[6]	[6]	[2]	[2]

TABLE 9.1.4-2b

EPDCCH candidates monitored by a UE (One
Localised EPDCCH-PRB-set - Case 3)

Number of PDCCH candidates M_p ^(L)for Case 3

N_RB ^X ^p	L = 1	L = 2	L = 4	L = 8

2	[8]	[4]	[2]	[1]
4	[6]	[6]	[2]	[2]
8	[6]	[6]	[2]	[2]

TABLE 9.1.4-3a

EPDCCH candidates monitored by a UE
(Two Distributed EPDCCH-PRB-sets - Case 1, Case 2)

	Number of PDCCH candidates	Number of PDCCH candidates
	[M_p1 ^(L), M_p2 ^(L)] for Case 1	[M_p1 ^(L), M_p2 ^(L)] for Case 2

N_RB ^Xp ₁	N_RB ^Xp ₂	L = 2	L = 4	L = 8	L = 16	L = 32	L = 1	L = 2	L = 4	L = 8	L = 16

2	2	[4, 4]	[2, 2]	[1, 1]	[0, 0]	[0, 0]	[4, 4]	[2, 2]	[1, 1]	[0, 0]	[0, 0]
4	4	[3, 3]	[3, 3]	[1, 1]	[1, 1]	[0, 0]	[3, 3]	[3, 3]	[1, 1]	[1, 1]	[0, 0]
8	8	[3, 3]	[2, 2]	[1, 1]	[1, 1]	[1, 1]	[3, 3]	[2, 2]	[1, 1]	[1, 1]	[1, 1]
4	2	[5, 3]	[3, 2]	[1, 1]	[1, 0]	[0, 0]	[5, 3]	[3, 2]	[1, 1]	[1, 0]	[0, 0]
8	2	[4, 2]	[4, 2]	[1, 1]	[1, 0]	[1, 0]	[4, 2]	[4, 2]	[1, 1]	[1, 0]	[1, 0]
8	4	[3, 3]	[2, 2]	[2, 1]	[1, 1]	[1, 0]	[3, 3]	[2, 2]	[2, 1]	[1, 1]	[1, 0]

TABLE 9.1.4-3b

EPDCCH candidates monitored by a UE
(Two Distributed EPDCCH-PRB-sets - Case 3)

	Number of PDCCH candidates
	[M_p1 ^(L), M_p2 ^(L)] for Case 3

N_RB ^Xp ₁	N_RB ^Xp ₂	L = 1	L = 2	L = 4	L = 8	L = 16

2	2	[2, 2]	[3, 3]	[2, 2]	[1, 1]	[0, 0]
4	4	[2, 2]	[2, 2]	[2, 2]	[1, 1]	[1, 1]
8	8	[2, 2]	[2, 2]	[2, 2]	[1, 1]	[1, 1]
4	2	[3, 1]	[3, 2]	[3, 1]	[1, 1]	[1, 0]
8	2	[3, 1]	[4, 1]	[3, 1]	[1, 1]	[1, 0]
8	4	[2, 2]	[2, 2]	[2, 2]	[1, 1]	[1, 1]

TABLE 9.1.4-4a

EPDCCH candidates monitored by a UE
(Two Localised EPDCCH-PRB-sets - Case 1, Case 2)

	Number of PDCCH	Number of PDCCH
	candidates	candidates [M_p1 ^(L), M_p2 ^(L)]
	[M_p1 ^(L), M_p2 ^(L)]for Case 1	for Case 2

N_RB ^Xp ₁	N_RB ^Xp ₂	L = 2	L = 4	L = 8	L = 16	L = 1	L = 2	L = 4	L = 8

2	2	[4, 4]	[2, 2]	[1, 1]	[0, 0]	[4, 4]	[2, 2]	[1, 1]	[0, 0]
4	4	[3, 3]	[3, 3]	[1, 1]	[1, 1]	[3, 3]	[3, 3]	[1, 1]	[1, 1]
8	8	[3, 3]	[3, 3]	[1, 1]	[1, 1]	[3, 3]	[3, 3]	[1, 1]	[1, 1]
4	2	[4, 3]	[4, 2]	[1, 1]	[1, 0]	[4, 3]	[4, 2]	[1, 1]	[1, 0]
8	2	[5, 2]	[4, 2]	[1, 1]	[1, 0]	[5, 2]	[4, 2]	[1, 1]	[1, 0]
8	4	[3, 3]	[3, 3]	[1, 1]	[1, 1]	[3, 3]	[3, 3]	[1, 1]	[1, 1]

TABLE 9.1.4-4b

EPDCCH candidates monitored by a UE (Two
Localised EPDCCH-PRB-sets - Case 3)

	Number of PDCCH candidates
	[M_p1 ^(L), M_p2 ^(L)] for Case 3

N_RB ^Xp ¹	N_RB ^Xp ²	L = 2	L = 4	L = 8	L = 16

2	2	[3, 3]	[3, 3]	[1, 1]	[1, 1]
4	4	[3, 3]	[3, 3]	[1, 1]	[1, 1]
8	8	[3, 3]	[3, 3]	[1, 1]	[1, 1]
4	2	[4, 2]	[4, 2]	[1, 1]	[1, 1]
8	2	[4, 2]	[4, 2]	[1, 1]	[1, 1]
8	4	[3, 3]	[3, 3]	[1, 1]	[1, 1]

TABLE 9.1.4-5a

EPDCCH candidates monitored by a UE
(One localised EPDCCH-PRB-set and one distributed EPDCCH-PRB-set, - Case 1, Case 2;
p₁is the identity of the localised EPDCCH-PRB-set, p₂is the identity
of the distributed EPDCCH-PRB-set)

N_RB ^Xp ₁	N_RB ^Xp ₂	L = 2	L = 4	L = 8	L = 16	L = 32	L = 1	L = 2	L = 4	L = 8	L = 16

2	2	[4, 4]	[2, 2]	[1, 1]	[0, 0]	[0, 0]	[4, 4]	[2, 2]	[1, 1]	[0, 0]	[0, 0]
4	4	[4, 2]	[4, 3]	[0, 2]	[0, 1]	[0, 0]	[4, 2]	[4, 3]	[0, 2]	[0, 1]	[0, 0]
8	8	[4, 1]	[4, 2]	[0, 2]	[0, 2]	[0, 1]	[4, 1]	[4, 2]	[0, 2]	[0, 2]	[0, 1]
2	4	[4, 3]	[2, 4]	[0, 2]	[0, 1]	[0, 0]	[4, 3]	[2, 4]	[0, 2]	[0, 1]	[0, 0]
2	8	[4, 1]	[2, 2]	[0, 4]	[0, 2]	[0, 1]	[4, 1]	[2, 2]	[0, 4]	[0, 2]	[0, 1]
4	2	[5, 2]	[4, 2]	[1, 1]	[1, 0]	[0, 0]	[5, 2]	[4, 2]	[1, 1]	[1, 0]	[0, 0]
4	8	[4, 1]	[4, 2]	[0, 2]	[0, 2]	[0, 1]	[4, 1]	[4, 2]	[0, 2]	[0, 2]	[0, 1]
8	2	[5, 1]	[4, 2]	[2, 1]	[1, 0]	[0, 0]	[5, 1]	[4, 2]	[2, 1]	[1, 0]	[0, 0]
8	4	[6, 1]	[4, 2]	[0, 2]	[0, 1]	[0, 0]	[6, 1]	[4, 2]	[0, 2]	[0, 1]	[0, 0]

TABLE 9.1.4-5b

EPDCCH candidates monitored by a UE
(one distributed EPDCCH-PRB-set and one localised EPDCCH-PRB-set -
Case 1, Case 3); p₁is the identity of the localised EPDCCH-PRB-set,
p₂is the identity of the distributed EPDCCH-PRB-set)

	Number of PDCCH candidates
	[M_p1 ^(L), M_p2 ^(L)] for Case 3

N_RB ^Xp ₁	N_RB ^Xp ₂	L = 1	L = 2	L = 4	L = 8	L = 16

2	2	[4, 1]	[4, 2]	[2, 2]	[0, 1]	[0, 0]
4	4	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]
8	8	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]
2	4	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]
2	8	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]
4	2	[4, 1]	[4, 1]	[2, 2]	[1, 1]	[0, 0]
4	8	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]
8	2	[4, 1]	[4, 1]	[4, 1]	[0, 1]	[0, 0]
8	4	[4, 1]	[4, 1]	[2, 2]	[0, 1]	[0, 1]

If DMRS and PSS/SSS can coexist in the same PRB pair (i.e., any alternative other than Alt.3b is chosen), PDSCH demodulated with DMRS and ePDCCH can be scheduled in the PRB pairs containing PSS/SSS (e.g., the central 6 PRB). However, the number of available resource elements (REs) would be different among the PRB pairs containing PSS/SSS and the PRB pairs not containing PSS/SSS given that PSS/SSS may occupy part of the downlink bandwidth. It is not clear how to determine the ePDCCH aggregation level set and blind decoding attempt split.
Various embodiments disclosed herein are directed to methods for determining the ePDCCH aggregation level set and blind decoding attempt split when the numbers of available REs between different PRB pairs are different. For example, according to one embodiment, a restriction is made so that at least within a subframe that the ePDCCH candidates come from the PRB pair(s) with the same number of available REs. Moreover, the number is used to determine ePDCCH aggregation level set and blind decoding attempt split. Alternatively, another restriction is made such that the numbers of available REs correspond to the same ePDCCH aggregation level set and blind decoding attempt split. In another embodiment, the ePDCCH candidates come from the PRB pairs with different numbers of available REs and a specific rule is used to derive a parameter for determining the ePDCCH aggregation level set and blind decoding attempt split. More specifically, ePDCCH can be received from the PRB pairs with different numbers of available REs.
In one embodiment, one or more PRB pair(s) containing PSS/SSS is allowed to receive PDSCH demodulated with DMRS while it is not allowed to receive ePDCCH. In another embodiment, at least within a TTI containing PSS/SSS, a UE receives ePDCCH on either PRB pair(s) containing PSS/SSS or PRB pair(s) not containing PSS/SSS. More specifically, in one example, all PRBs configured for ePDCCH for the UE either contain PSS/SSS or do not contain PSS/SSS. In another example, ePDCCH is received on the PRB pairs containing the signal or the PRB pairs not containing the signal based on which camp contains more PRB pairs that are configured for ePDCCH. In still another example, PDCCH is received on the PRB pairs containing the signal or the PRB pairs not containing the signal based on an indication.
Alternatively, in one embodiment, in at least one subframe, if there is more than one number of available resource elements among PRBs pairs, a number is chosen to be used to determine the ePDCCH aggregation level set and blind decoding attempt split. For example, a larger number can be chosen for determining the ePDCCH aggregation level set and blind decoding attempt split. More specifically, the number of available resource elements in the PRB pairs not containing PSS/SSS is used to determine the ePDCCH aggregation level set and blind decoding attempt split. In another example, a smaller number is chosen for determining the ePDCCH aggregation level set and blind decoding attempt split. More specifically, the number of available resource elements in the PRB pairs containing PSS/SSS is used to determine the ePDCCH aggregation level set and blind decoding attempt split. In yet another example, a number is chosen based on the number of available resource elements in majority PRB pairs. In another embodiment, in at least one subframe, if there is more than one number of available resource elements among PRBs pairs, the ePDCCH aggregation level set and blind decoding attempt split associated with a number of available resource elements is used, wherein the number is chosen from the more than one number.
In another embodiment, in at least in a subframe, if there is more than one number of available resource elements among PRBs pairs, a value determines the ePDCCH aggregation level set and blind decoding attempt split, wherein the value is derived from the more than one number. For example, in one embodiment, the value is an average of the more than one number. More specifically, ePDCCH is received on PRB pairs with different numbers of available resource elements.
Referring back to FIGS. 3 and 4, the device 300 includes a program code 312 stored in memory 310. In one embodiment, the CPU 308 could execute program code 312 to execute one or more of the following: (i) have, in at least one subframe, more than one number of available resource elements among Physical Resource Block (PRB) pairs in a cell, and (ii) to receive an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same number of available resource elements.
In another embodiment, the CPU 308 could execute the program code 312 to execute one or more of the following: (i) have, in at least one subframe, more than one number of available resource elements among Physical Resource Block (PRB) pairs in a cell, and (ii) to use a rule to determine the ePDCCH aggregation level set and blind decoding attempt split.
In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
Various aspects of the disclosure have been described above. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. As an example of some of the above concepts, in some aspects concurrent channels may be established based on pulse repetition frequencies. In some aspects concurrent channels may be established based on pulse position or offsets. In some aspects concurrent channels may be established based on time hopping sequences. In some aspects concurrent channels may be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as “software” or a “software module”), or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
In addition, the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (“IC”), an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a “processor”) such the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Moreover, in some aspects any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects a computer program product may comprise packaging materials.
While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.

Claims

1. A method in a wireless communication system, the method comprising:

having, in at least one subframe, numbers of available resource elements among different Physical Resource Blocks (PRBs) are different in a cell; and

receiving an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same as the number of available resource elements.

2. The method of claim 1, wherein the numbers of available resource elements are different due to the presence of a signal.

3. The method of claim 1, further comprising: determining the ePDCCH aggregation level set and blind decoding attempt split based on the number of available resource elements with PRB pairs receiving ePDCCH.

4. The method of claim 2, wherein ePDCCH cannot be received on the PRB pair containing the signal, and wherein Physical Downlink Control Channel (PDSCH) demodulated with a Demodulation Reference Signal (DMRS) can be received on the PRB pair containing the signal.

5. The method of claim 2, wherein the ePDCCH is received on either PRB pairs containing the signal or the PRB pairs not containing the signal.

6. The method of claim 5, wherein whether ePDCCH is received on PRB pairs containing the signal or the PRB pairs not containing the signal depends on which type of PRB pairs are the majority among the PRB pairs configured for ePDCCH.

7. A method in a wireless communication system, the method comprising:

having, in at least one subframe, more than one number of available resource elements among PRBs pairs in a cell; and

using a value to determine the ePDCCH aggregation level set and blind decoding attempt split.

8. The method of claim 7, the numbers of available resource elements are different due to the presence of a signal.

9. The method of claim 7, ePDCCH is received on PRB pairs with different numbers of available resource elements.

10. The method of claim 7, wherein the value is based on one of the more than one number.

11. The method of claim 7, wherein the value is derived from the more than one number.

12. The method of claim 8, wherein the signal is Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS).

13. A communication device in a wireless communication system, the communication device comprising:

a control circuit;

a processor installed in the control circuit;

a memory installed in the control circuit and operatively coupled to the processor;

wherein the processor is configured to execute a program code stored in memory to:

have in at least one subframe, numbers of available resource elements among Physical Resource Blocks (PRBs) in a cell are different; and

receive an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same as the number of available resource elements.

14. The communication device of claim 13, wherein the number of available resource elements is different due to the presence of a signal.

15. The communication device of claim 13, wherein the ePDCCH is received on either PRB pairs containing the signal or the PRB pairs not containing the signal.

16. The communication device of claim 13, wherein the processor is configured to execute a program code stored in memory to determine the ePDCCH aggregation level set and blind decoding attempt split based on the number of available resource elements with PRB pairs receiving ePDCCH.

17. The communication device of claim 15, wherein ePDCCH cannot be received on the PRB pair containing the signal, and wherein Physical Downlink Control Channel (PDSCH) demodulated with a Demodulation Reference Signal (DMRS) can be received on the PRB pair containing the signal.

18. The communication device of claim 13, wherein the processor is configured to execute a program code stored in memory to provide an indication whether ePDCCH is received on the PRB pairs containing the signal or the PRB pairs not containing the signal.

19. The communication device of claim 15, wherein whether ePDCCH is received on PRB pairs containing the signal or the PRB pairs not containing the signal depends on which type of PRB pairs is majority among the PRB pairs configured for ePDCCH.