Random access procedure
The invention relates to a method of random access, comprising: a higher layer instructs the lower layer to transmit a random access preamble, wherein the timing transmission of the random access preamble is adjusted by the lower layer according the triggered resources.
1. A method of random access, the method comprising:
transmitting, by a higher layer, an indicator to a lower layer, indicating to the lower layer to transmit a random access preamble, wherein the indicator includes a cause value indicating a cause of transmission of the random access preamble; and
transmitting, by the lower layer, the random access preamble,
wherein:
when the cause value indicates re-transmission due to a received random access response not corresponding to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+5), wherein the subframe n is the subframe in which the random access response is received; or
when the cause value indicates re-transmission due to no random access response being received in response to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+4), wherein the subframe n is the last subframe of the random access response window.
2. The method according to claim 1 , wherein the higher layer corresponds to a Medium Access Control layer, and the lower layer corresponds to a Physical layer.
3. The method according to claim 1 , wherein, when the cause value indicates an initial random access preamble transmission, the random access preamble is transmitted in a subframe where a physical random access channel (PRACH) resource is available.
4. A user equipment comprising:
a transceiver for transmitting a random access preamble and for receiving a random access response within a random access response window,
wherein the user equipment is operable at least on a higher layer and a lower layer,
wherein the higher layer is configured to transmit an indicator to the lower layer, indicating to the lower layer to transmit a random access preamble, the indicator including a cause value indicating a cause of transmission of the random access preamble, and
wherein the lower layer is configured to transmit the random access preamble,
wherein:
when the cause value indicates re-transmission due to a received random access response not corresponding to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+5), wherein the subframe n is the subframe in which the random access response is received; or
when the cause value indicates re-transmission due to no random access response being received in response to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+4), wherein the subframe n is the last subframe of the random access response window.
5. The user equipment according to claim 4 , wherein the higher layer corresponds to a Medium Access Control layer, and the lower layer corresponds to a Physical layer.
6. The user equipment according to claim 4 , wherein, when the cause value indicates an initial random access preamble transmission, the random access preamble is transmitted in a subframe where a physical random access channel (PRACH) resource is available.
7. A computer program product for a data-processing device, the computer program product comprising a set of instructions which, when loaded into the data-processing device, causes the device to:
transmit, by a higher layer, an indicator to a lower layer, indicating to the lower layer to transmit a random access preamble, wherein the indicator includes a cause value indicating a cause of transmission of the random access preamble; and
transmit, by the lower layer, the random access preamble,
wherein:
when the cause value indicates re-transmission due to a received random access response not corresponding to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+5), wherein the subframe n is the subframe in which the random access response is received; or
when the cause value indicates re-transmission due to no random access response being received in response to a previously transmitted random access preamble, the random access preamble is transmitted no later than in a subframe (n+4), wherein the subframe n is the last subframe of the random access response window.