Time alignment in multicarrier OFDM network
First Claim
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1. A method comprising:
- a) receiving, by a wireless device, at least one radio resource control message from a base station, said at least one radio resource control message;
i) causing configuration of a plurality of carriers comprising a first carrier and at least one second carrier; and
ii) comprising;
(1) a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a second carrier group, said second carrier group being one of a plurality of carrier groups, said second carrier group comprising a second subset of said at least one second carrier;
(2) a plurality of second uplink carrier parameters for a second uplink carrier of said second carrier; and
(3) a plurality of random access resource parameters identifying random access resources for said second carrier;
b) receiving, by said wireless device from said base station, a control command causing said wireless device to transmit a random access preamble on said second uplink carrier, said control command comprising a preamble index corresponding to said random access preamble;
c) transmitting, by said wireless device, said random access preamble on said random access resources on said second uplink carrier, transmission timing of said random access preamble being determined, at least in part, by employing a synchronization signal transmitted on one of at least one downlink carrier in said second carrier group, uplink transmissions in said second carrier group employing said synchronization signal as timing reference;
d) receiving, by said wireless device, a long time alignment command on said first carrier in response to said random access preamble transmission, said long time alignment command comprising said preamble index and a long time adjustment value;
e) receiving, by said wireless device, at least one short time alignment command from said base station, said short time alignment command comprising;
i) a short time adjustment value, said short time adjustment value range is substantially smaller than said long time adjustment value range; and
ii) an index identifying said second carrier group; and
f) applying, by said wireless device, said short time adjustment value to uplink signals transmitted on all activated uplink carriers in said second carrier group such that said base station receives substantially aligned uplink signals in frames and subframes of said second carrier group.
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Abstract
A base station receives uplink signals from a wireless device and transmits at least one time alignment command computed based, at least in part, on timing of the received uplink signals. The time alignment command comprises a time adjustment value and an index identifying a carrier group.
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Citations
19 Claims
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1. A method comprising:
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a) receiving, by a wireless device, at least one radio resource control message from a base station, said at least one radio resource control message; i) causing configuration of a plurality of carriers comprising a first carrier and at least one second carrier; and ii) comprising; (1) a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a second carrier group, said second carrier group being one of a plurality of carrier groups, said second carrier group comprising a second subset of said at least one second carrier; (2) a plurality of second uplink carrier parameters for a second uplink carrier of said second carrier; and (3) a plurality of random access resource parameters identifying random access resources for said second carrier; b) receiving, by said wireless device from said base station, a control command causing said wireless device to transmit a random access preamble on said second uplink carrier, said control command comprising a preamble index corresponding to said random access preamble; c) transmitting, by said wireless device, said random access preamble on said random access resources on said second uplink carrier, transmission timing of said random access preamble being determined, at least in part, by employing a synchronization signal transmitted on one of at least one downlink carrier in said second carrier group, uplink transmissions in said second carrier group employing said synchronization signal as timing reference; d) receiving, by said wireless device, a long time alignment command on said first carrier in response to said random access preamble transmission, said long time alignment command comprising said preamble index and a long time adjustment value; e) receiving, by said wireless device, at least one short time alignment command from said base station, said short time alignment command comprising; i) a short time adjustment value, said short time adjustment value range is substantially smaller than said long time adjustment value range; and ii) an index identifying said second carrier group; and f) applying, by said wireless device, said short time adjustment value to uplink signals transmitted on all activated uplink carriers in said second carrier group such that said base station receives substantially aligned uplink signals in frames and subframes of said second carrier group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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a) transmitting, by a base station, a first synchronization signal on a first downlink carrier of a first carrier in a plurality of carriers; b) receiving, by said base station from a wireless device, a random access preamble on a first uplink carrier of said first carrier, transmission timing of said random access preamble determined based, at least in part, on said first synchronization signal; c) transmitting, by said base station, at least one radio resource control message, said at least one radio resource control message; (i) causing configuration of at least one additional carrier in said wireless device; (ii) comprising a carrier group index for an additional carrier in said at least one additional carrier, said carrier group index identifying a second carrier group, said second carrier group being one of a plurality of carrier groups, said second carrier group comprising a subset of said at least one additional carrier; d) transmitting, by said base station to said wireless device, signals on said first carrier and said at least one additional carrier, wherein downlink frames and subframes transmission timing for said first carrier and said at least one additional carrier are substantially time aligned with each other; e) receiving, by said base station, uplink signals from said wireless device on said additional carrier; and f) transmitting, by said base station to said wireless device, at least one time alignment command computed based, at least in part, on timing of said received uplink signals, said time alignment command comprising; i) a time adjustment value; and ii) an index identifying said second carrier group; and wherein said at least one time alignment command causes substantial alignment of reception timing of uplink signals in frames and subframes of said second carrier group; and wherein uplink transmission timing of frames and subframes of said first carrier and said additional carrier employ different synchronization signals as timing reference and are adjusted in response to different time alignment commands. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method comprising:
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a) transmitting, by said base station, at least one radio resource control message, said at least one radio resource control message; (i) causing configuration of a plurality of carriers comprising a first carrier and at least one additional carrier in said wireless device; (ii) comprising a carrier group index for a carrier in said plurality of carriers, said carrier group index identifying a carrier group, said carrier group being one of a plurality of carrier groups, said plurality of carrier groups comprising; (1) a first carrier group comprising a first subset of said plurality of carriers, said first subset comprising said first carrier; and (2) a second carrier group comprising a subset of said at least one additional carrier; b) transmitting, by said base station to said wireless device, signals on said plurality of carriers, wherein downlink frames and subframes transmission timing for said first carrier and said at least one additional carrier are substantially time aligned with each other; c) receiving, by said base station, uplink signals from said wireless device on said plurality of carriers; and d) transmitting, by said base station to said wireless device, at least one time alignment command, said time alignment command comprising; i) a time adjustment value; and ii) an index identifying one carrier group; and wherein uplink transmission timing of frames and subframes in said first carrier group and said second carrier group employ different synchronization signals on different carriers as timing reference and are adjusted in response to different time alignment commands. - View Dependent Claims (18, 19)
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Specification