Timing alignment in an LTE system
First Claim
1. A method for uplink time alignment in a cellular communications system, comprising:
- transmitting a random access preamble to the controlling node as part of a contention based random access procedure;
receiving a random access response from the controlling node in response to the random access preamble, wherein the random access preamble comprises a second timing advance value;
after receiving the random access response, determining whether a first timing advance value received from the controlling node before transmission of the random access preamble is valid;
if the first timing advance value is valid, transmitting to the controlling node in accordance with the first timing advance value after receiving the random access response; and
if the first timing advance is not valid, transmitting to the controlling node in accordance with the second timing advance value.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for use in a user terminal in a cellular communications system. According to the method, the user terminal applies a first timing advance value to its transmissions to a controlling node, and the user terminal requests communication with the controlling node in a contention based procedure by transmitting an access request (MSG 1), in response to which the controlling node transmits an initiation message (MSG 2) along with a second timing advance value. According to the method, the user terminal uses the first timing advance value if the user terminal loses the contention based procedure, i.e. if the controlling node subsequently continues the initiated communication with said other user terminal.
17 Citations
20 Claims
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1. A method for uplink time alignment in a cellular communications system, comprising:
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transmitting a random access preamble to the controlling node as part of a contention based random access procedure; receiving a random access response from the controlling node in response to the random access preamble, wherein the random access preamble comprises a second timing advance value; after receiving the random access response, determining whether a first timing advance value received from the controlling node before transmission of the random access preamble is valid; if the first timing advance value is valid, transmitting to the controlling node in accordance with the first timing advance value after receiving the random access response; and if the first timing advance is not valid, transmitting to the controlling node in accordance with the second timing advance value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A user terminal for transmitting data in a cellular communications system, the user terminal comprising:
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a transmitter arranged for transmitting to a controlling node in accordance with a timing advance value; and
for transmitting a random access preamble to the controlling node as part of a contention based random access procedure;a receiver arranged for receiving a random access response from the controlling node in response to the random access preamble, wherein the random access preamble comprises a second timing advance value; and one or more circuits arranged to; determine whether a previously received first timing advance value is valid when the second timing advance value is received; if the first timing advance value is valid, control the transmitter to continue to transmit to the controlling node in accordance with the first timing advance value after receiving the random access response; and if the first timing advance is not valid, control the transmitter to transmit to the controlling node in accordance with the second timing advance value.
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12. A user terminal for use in a cellular communications system, the user terminal comprising:
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a transmitter configured to request communication with a controlling node in a contention based random access procedure by transmitting a random access preamble to the controlling node; and a receiver configured to receive, in response to the random access preamble, a random access response with a second timing advance value; one or more control circuits configured to; determine whether a first timing advance value, received before the random access response, is valid at receipt of the second timing advance value; and ignore the second timing advance value if the first timing advance value is determined to be valid and thereby control the transmitter to apply the first timing advance value to transmissions to the controlling node, and otherwise control the transmitter to apply the second timing advance value to transmissions to the controlling node. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method in a user terminal configured for use in a wireless communication network, said method comprising:
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receiving a first timing advance value at the user terminal; performing a contention-based random access procedure, in which the user terminal attempts to access the network and receives a second timing advance value; determining whether the first timing advance value is valid at receipt of the second timing advance value; and ignoring the second timing advance value and continuing to use the first timing advance value at the user terminal for transmitting to the network on the uplink if the first timing advance value is determined to be valid, and otherwise using the second timing advance value at the user terminal for transmitting to the network on the uplink.
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Specification