METHOD, BASE STATION, AND USER EQUIPMENT FOR TRANSMITTING DOWNLINK CONTROL SIGNAL
The application pertains to a method for transmitting a downlink control signal. A base station maps an enhanced physical downlink control channel (E-PDCCH) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of OFDM symbols used by the E-PDCCH of a user equipment (UE). The E-PDCCH is sent to the UE from the base station by using the resource elements, where the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed. Because the E-PDCCH is mapped sequentially to resource elements for transmitting the E-PDCCH in each OFDM symbol according to an order of OFDM symbols used by the E-PDCCH of the UE, different control channel elements of E-PDCCHs at different aggregation levels will not include a same E-PDCCH modulation symbol, thereby ensuring that the UE judges a start position of the E-PDCCH correctly.
1 - 68 . (canceled)
69 . A method for transmitting a downlink control signal, comprising:
mapping, by a base station, an enhanced physical downlink control channel (E-PDCCH) of a user equipment (UE) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the E-PDCCH of the UE; and
sending, by the base station, the E-PDCCH to the UE by using the mapped resource elements;
wherein the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed.
70 . The method according to claim 69 , wherein mapping the E-PDCCH sequentially to the resource elements comprises:
mapping the E-PDCCH sequentially to resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer.
71 . The method according to claim 70 , wherein mapping the E-PDCCH sequentially to the resource elements occupied by the L control channel elements in each OFDM symbol comprises:
mapping modulation symbols of the E-PDCCH with index numbers of
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N
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sequentially to a set R l of resource elements,
wherein the set R l is a set of resource elements occupied by the l th control channel element among the L control channel elements comprised in the E-PDCCH in the OFDM symbol; j 0 is a start position of the modulation symbols of the E-PDCCH mapped in the OFDM symbol; N l is the quantity of the resource elements in the set R l ; and N l , j 0 , l and q are integers.
72 . The method according to claim 69 , wherein mapping the E-PDCCH sequentially to the resource elements comprises:
mapping the E-PDCCH sequentially to resource elements occupied by L control channel elements allocated to the E-PDCCH according to an order of subcarriers in each OFDM symbol, wherein L is an integer.
73 . The method according to claim 72 , wherein mapping the E-PDCCH sequentially to the resource elements occupied by L control channel elements allocated to the E-PDCCH comprises:
mapping modulation symbols of the E-PDCCH with index numbers of j 0 +[0, . . . , N−1] sequentially to a set R of resource elements,
wherein j 0 is a start position of the modulation symbols of the E-PDCCH mapped in the OFDM symbol; the set R is a set of resource elements occupied by the L control channel elements comprised in the E-PDCCH in the OFDM symbol; N is the quantity of the resource elements in the set R; and N and j 0 are integers.
74 . A method for receiving a downlink control signal, comprising:
receiving, by a user equipment (UE), a downlink subframe from a base station;
extracting, by the UE, modulation symbols of a candidate enhanced physical downlink control channel (E-PDCCH) sequentially from resource elements mapped to the candidate E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the candidate E-PDCCH in the downlink subframe; and
performing a decoding and a cyclic redundancy check (CRC) on the candidate E-PDCCH;
wherein the E-PDCCH of the UE and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH of the UE are frequency-division multiplexed.
75 . The method according to claim 74 , wherein extracting the modulation symbols of the candidate E-PDCCH comprises:
extracting the modulation symbols of the candidate E-PDCCH sequentially from resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer.
76 . The method according to claim 75 , wherein extracting the modulation symbols of the candidate E-PDCCH sequentially from resource elements occupied by the L control channel elements in each OFDM symbol comprises:
extracting modulation symbols of the candidate E-PDCCH and with index numbers of
j
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∑
q
=
0
l
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1
N
q
+
[
0
,
…
,
N
l
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1
]
from a set R l of resource elements,
wherein the set R l is a set of resource elements occupied by the l th control channel element among the L control channel elements comprised in the modulation symbols of the candidate E-PDCCH in the OFDM symbol; j 0 is a start position of the modulation symbols of the candidate E-PDCCH mapped in the OFDM symbol; N l is the quantity of the resource elements in the set R l ; and N l , j 0 , l and q are integers.
77 . The method according to claim 74 , wherein extracting the modulation symbols of the candidate E-PDCCH comprises:
extracting, by the UE, the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH according to an order of subcarriers in each OFDM symbol.
78 . The method according to claim 77 , wherein extracting the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH comprises:
extracting modulation symbols of the candidate E-PDCCH and with index numbers of j 0 +[0, . . . , N−1] from a set R of resource elements,
wherein j 0 is a start position of the modulation symbols of the candidate E-PDCCH mapped in the OFDM symbol; the set R is a set of resource elements occupied by the L control channel elements comprised in the modulation symbols of the candidate E-PDCCH in the OFDM symbol; N is the quantity of the resource elements in the set R; and N and j 0 are integers.
79 . A base station, comprising:
a mapping processor, configured to map an enhanced physical downlink control channel (E-PDCCH) of a user equipment (UE) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the E-PDCCH of the UE; and
a transmitter, configured to send the E-PDCCH to the UE by using the mapped resource elements;
wherein the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed.
80 . The base station according to claim 79 , wherein the mapping processor maps the E-PDCCH sequentially to resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer.
81 . The base station according to claim 79 , wherein the mapping processor maps the E-PDCCH sequentially to resource elements occupied by L control channel elements allocated to the E-PDCCH according to an order of subcarriers in each OFDM symbol.
82 . A user equipment, comprising:
a receiver, configured to receive a downlink subframe from a base station; and
an extracting processor, configured to sequentially extract modulation symbols of a candidate enhanced physical downlink control channel (E-PDCCH) sequentially from resource elements mapped to the candidate E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the candidate E-PDCCH in the downlink subframe, and perform a decoding and a cyclic redundancy check (CRC) on the candidate E-PDCCH;
wherein an E-PDCCH of the user equipment and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH of the user equipment are frequency-division multiplexed.
83 . The user equipment according to claim 82 , wherein the extracting processor extracts the candidate E-PDCCH sequentially from resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the candidate E-PDCCH in the OFDM symbol, wherein L is an integer.
84 . The user equipment according to claim 82 , wherein the extracting processor extracts the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH according to an order of subcarriers in each OFDM symbol.