Method and network node of wireless communication network for handling random access
Disclosed is a method and a network node for handling random access in a wireless communication network. The method includes receiving a random access preamble when a first number of receivers are active and a second number of the receivers are inactive, and sending a random access response to the received random access preamble. The method further includes determining whether a reception requirement for a subsequent random access procedure message is fulfilled, the subsequent random access procedure message being sent subsequent to the network node sending the random access response, the reception requirement being either whether the random access procedure message is received at the network node or whether the random access procedure message that is received has a sufficient quality, and when the reception requirement is determined not fulfilled, activating at least some of the inactive second number of receivers.
1 . A method performed by a network node of a wireless communication network, the network node having a plurality of receivers, the method comprising:
receiving, from a wireless device, a random access preamble when a first number of the plurality of receivers is active and a second number of the plurality of receivers is inactive;
sending, to the wireless device, a random access response, in response to the received random access preamble;
determining whether a reception requirement for a subsequent random access procedure message sent by the wireless device towards the network node is fulfilled, the subsequent random access procedure message being sent by the wireless device subsequent to the network node sending the random access response, the reception requirement being either whether the subsequent random access procedure message is received at the network node or whether the subsequent random access procedure message that is received has a sufficient quality; and
when the reception requirement is determined not fulfilled, activating at least some of the inactive second number of receivers.
2 . The method according to claim 1 , further comprising:
broadcasting, before the receiving of the random access preamble from the wireless device and in connection with inactivation of the second number of receivers, a configuration message for configuration of the random access preamble, the configuration message including a second configuration of the random access preamble that is more robust than a first configuration of the random access preamble that is broadcasted when no receivers or fewer receivers than the second number of receivers are inactivated, and wherein the random access preamble that is received is of the second configuration.
3 . The method according to claim 2 , wherein the second configuration is more robust than the first configuration in that a sequence is configured for the random access preamble that is longer in time in the second configuration than in the first configuration.
4 . The method according to claim 2 , wherein the second configuration of the broadcasted configuration message includes a shortened random access preamble periodicity compared to the first configuration.
5 . The method according to claim 1 , further comprising:
inactivating, before the receiving of the random access preamble, the second number of the plurality of receivers, based on one or more of: number of wireless devices connected to the network node; signal quality such as signal strength of wireless devices connected to the network node; network node backup battery level; network node temperature; cost of network node power; distortion of one or more of the plurality of receivers, and data traffic load between the network node and wireless devices connected to the network node.
6 . The method according to claim 1 , wherein the sent random access response comprises information on the subsequent random access procedure message, the information indicating to the wireless device to use more communication resources, a higher transmit power and/or a more robust coding for the subsequent random access procedure message compared to when the second number of receivers are active.
7 . The method according to claim 1 , further comprising:
receiving the subsequent random access procedure message sent by the wireless device in response to the sent random access response, and
wherein the reception requirement is whether the subsequent random access procedure message received has a sufficient quality, and wherein the reception requirement is determined not fulfilled when a signal quality of the subsequent random access procedure message is below a threshold.
8 . The method according to claim 7 , further comprising, when the signal quality of the received subsequent random access procedure message is determined to be below the threshold and at least some of the inactive second number of receivers have been activated, sending, towards the wireless device, a random access message subsequent to the subsequent random access procedure message.
9 . The method according to claim 1 , wherein the activating of at least some of the second number of receivers further triggers configuring a preamble received target power value and broadcasting the configured preamble received target power value in the cell in which the wireless device resides.
10 . The method according to claim 1 , wherein the reception requirement is whether the subsequent random access procedure message is received, and wherein the reception requirement is determined not fulfilled when the subsequent random access procedure message has not been received within a running time of a timer T started when the random access response was sent.
11 . The method according to claim 1 , further comprising, when the reception requirement is determined fulfilled:
sending, towards the wireless device, a random access message subsequent to the subsequent random access procedure message.
12 . A network node configured to operate in a wireless communication network, the network node having a plurality of receivers, the network node comprising a processing circuitry and a memory, said memory containing instructions executable by said processing circuitry, whereby the network node is operative to:
receive, from a wireless device, a random access preamble when a first number of the plurality of receivers is active and a second number of the plurality of receivers is inactive;
send, to the wireless device, a random access response, in response to the received random access preamble;
determine whether a reception requirement for a subsequent random access procedure message sent by the wireless device towards the network node is fulfilled, the subsequent random access procedure message being sent by the wireless device subsequent to the network node sending the random access response, the reception requirement being either whether the subsequent random access procedure message is received at the network node or whether the subsequent random access procedure message that is received has a sufficient quality; and
when the reception requirement is determined not fulfilled, activate at least some of the inactive second number of receivers.
13 . The network node according to claim 12 , further being operative to:
broadcast, before the receiving of the random access preamble from the wireless device and in connection with inactivation of the second number of receivers, a configuration message for configuration of the random access preamble, the configuration message including a second configuration of the random access preamble that is more robust than a first configuration of the random access preamble that is broadcasted when no receivers or fewer receivers than the second number of receivers are inactivated, and wherein the network node is operative for receiving the random access preamble of the second configuration.
14 . The network node according to claim 13 , wherein the second configuration is more robust than the first configuration in that a sequence is configured for the random access preamble that is longer in time in the second configuration than in the first configuration.
15 . The network node according to claim 13 , wherein the second configuration of the broadcasted configuration message includes a shortened random access preamble periodicity compared to the first configuration.
16 . The network node according to claim 12 , further being operative to:
inactivate, before the receiving of the random access preamble, the second number of the plurality of receivers, based on one or more of: number of wireless devices connected to the network node; signal quality such as signal strength of wireless devices connected to the network node; network node backup battery level; network node temperature; cost of network node power; distortion of one or more of the plurality of receivers, and data traffic load between the network node and wireless devices connected to the network node.
17 . The network node according to claim 12 , wherein the random access response comprises information on the subsequent random access procedure message, the information indicating to the wireless device to use more communication resources, a higher transmit power and/or a more robust coding for the subsequent random access procedure message compared to when the second number of receivers are active.
18 . The network node according to claim 12 , further being operative to:
receive the subsequent random access procedure message sent by the wireless device in response to the sent random access response, and wherein the reception requirement is whether the subsequent random access procedure message received has a sufficient quality, and wherein the network node is operative to determine that the reception requirement is not fulfilled when a signal quality of the subsequent random access procedure message is below a threshold.
19 . The network node according to claim 18 , further being operative to, when the signal quality of the received subsequent random access procedure message is determined to be below the threshold and at least some of the inactive second number of receivers have been activated, send, towards the wireless device, a random access message subsequent to the subsequent random access procedure message.
20 . The network node according to claim 12 , operative to trigger configuring of a preamble received target power value and broadcasting the configured preamble received target power value in the cell in which the wireless device resides, in response to the activating of at least some of the second number of receivers.