Ad hoc radio base station
An ad hoc radio base station and a method for locating a user apparatus are presented. The method comprises setting up two ad hoc cells, a first cell of the two ad hoc cells providing an omnidirectional cell and a second cell of the ad hoc cells providing a directional cell, utilizing a set of directional or beamforming antennas, the main lobes of the antennas of the cells being directed at different directions from each other, one antenna of the second cell being active at a time; setting up a radio connection in one of the two ad hoc cells to an user apparatus; obtaining information on the signal-to-noise ratio measured by the user apparatus from of the signal received by the user apparatus and Timing Advance required on the radio connection; transmitting a redirection message to other cell in the first radio connection to the user apparatus.
1. An ad hoc radio base station, comprising: one or more radio transceivers configured to receive and transmit in a cellular radio network; and one or more processors configured to cause performance of at least the following: setting up two ad hoc cells, each cell on a channel number with a Physical Cell ID, PCID and a Tracking Area Code, TAC or a Scrambling Code and a Location Area Code (LAC)/Routing Area Code (RAC); a first cell of the two ad hoc cells providing an omnidirectional cell; a second cell of the ad hoc cells providing a directional cell, utilizing a set of directional or beamforming antennas, main lobes of the antennas of the cells being directed at different directions from each other, one antenna of the second cell being active at a time; setting up a radio connection in one of the two ad hoc cells to an user apparatus using a Random Access Channel, RACH, procedure; obtaining information on the signal-to-noise ratio measured by the user apparatus from of the signal received by the user apparatus and Timing Advance required on the radio connection; transmitting a Radio Resource Control, RRC, release message with a redirection to other cell of the two ad hoc cells in the radio connection to the user apparatus, repeating the above obtaining and transmitting steps a given number of times; determining the location of the user apparatus based on the obtained information.
2. The ad hoc radio base station of claim 1 , wherein the main lobes of the directional or beamforming antennas of the second cell are perpendicular to each other.
3. The ad hoc radio base station of claim 1 , wherein the second cell of the ad hoc cells utilizes four directional or beamforming antennas each providing a main lobe on the same horizontal plane and perpendicular to each other and a fifth directional antenna, the main lobe of the fifth antenna being perpendicular to the main lobes of the four other directional antennas.
4. The ad hoc radio base station of claim 1 , wherein the one or more processors are configured to cause performance of the following:
if the user apparatus is being served by the second cell, transmitting the Radio Resource Control, RRC, release message with a redirection to the first cell; and
if the user apparatus is being served by the first cell, transmitting the Radio Resource Control, RRC, release message with a redirection to the second cell, wherein the second cell is configured to activate a directional or beamforming antenna which did not serve the user apparatus before transferring the user apparatus to the first cell.
5. The ad hoc radio base station of claim 1 , wherein the one or more processors are configured to cause performance of the following:
activating the directional or beamforming antennas in the second cell one by one at a time in a given order.
6. The ad hoc radio base station of claim 5 , wherein the main lobe of the fifth directional antenna is directed upwards if the cell is on the ground or downwards if the cell is airborne.
7. The ad hoc radio base station of claim 1 , wherein the one or more processors are configured to cause performance of the following:
determine a vector for two or more directional or beamforming antennas of the set of directional or beamforming antennas, the direction of the vector corresponding to the direction of the main lobe of the directional or beamforming antenna and the length of the vector corresponding to the signal-to-noise ratio measured by the user apparatus when being in radio connection utilizing the directional or beamforming antenna;
determine the location of the user apparatus based on the sum of the vectors.
8. The ad hoc radio base station of claim 1 , wherein the one or more processors are configured to cause performance of the following:
if the signal-to-noise ratio measured by the user apparatus when being in radio connection utilizing a given directional or beamforming antenna is below a given threshold, ignore the measurement when determining the location of the user apparatus.
9. A method for locating a user apparatus, comprising: setting up two ad hoc cells, each cell on a channel number with a Physical Cell ID, PCID and a Tracking Area Code, TAC or a Scrambling Code and a Location Area Code (LAC)/Routing Area Code (RAC); a first cell of the two ad hoc cells providing an omnidirectional cell; a second cell of the ad hoc cells providing a directional cell, utilizing a set of directional or beamforming antennas, main lobes of the antennas of the cells being directed at different directions from each other, one antenna of the second cell being active at a time; setting up a radio connection in one of the two ad hoc cells to an user apparatus using a Random Access Channel, RACH, procedure; obtaining information on the signal-to-noise ratio measured by the user apparatus from of the signal received by the user apparatus and Timing Advance required on the radio connection; transmitting a Radio Resource Control, RRC, release message with a redirection to other cell of the two ad hoc cells in the radio connection to the user apparatus, repeating the above obtaining and transmitting steps a given number of times; determining the location of the user apparatus based on the obtained information.
10. The method of claim 9 , wherein the main lobes of the directional antennas of the second cell are perpendicular to each other.
11. The method of claim 10 , wherein the second cell of the ad hoc cells utilizes four directional or beamforming antennas each providing a main lobe on the same horizontal plane and perpendicular to each other and a fifth directional antenna, the main lobe of the fifth antenna being perpendicular to the main lobes of the four other directional or beamforming antennas.
12. The method of claim 9 , further comprising:
transmitting the Radio Resource Control, RRC, release message with a redirection to the first cell, if the user apparatus is being served by the second cell; and
transmitting the Radio Resource Control, RRC, release message with a redirection to the second cell, if the user apparatus is being served by the first cell, wherein the second cell is configured to activate a directional or beamforming antenna which did not serve the user apparatus before transferring the user apparatus to the first cell.
13. The method of claim 9 , further comprising:
determining a vector for two or more directional or beamforming antennas of the set of directional or beamforming antennas, the direction of the vector corresponding to the direction of the main lobe of the directional or beamforming antenna and the length of the vector corresponding to the signal-to-noise ratio measured by the user apparatus when being in radio connection utilizing the directional or beamforming antenna;
determining the location of the user apparatus based on the sum of the vectors.
14. The method of claim 9 , further comprising:
activating the directional or beamforming antennas in the second cell one by one at a time in a given order.
15. A non-transitory computer-readable medium comprising computer program code, which, when executed by one or more microprocessors, causes performance of: setting up two ad hoc cells, each cell on a channel number with a Physical Cell ID, PCID and a Tracking Area Code, TAC or a Scrambling Code and a Location Area Code (LAC)/Routing Area Code (RAC); a first cell of the two ad hoc cells providing an omnidirectional cell; a second cell of the ad hoc cells providing a directional cell, utilizing a set of directional or beamforming antennas, main lobes of the antennas of the cells being directed at different directions from each other, one antenna of the second cell being active at a time; setting up a radio connection in one of the two ad hoc cells to an user apparatus using a Random Access Channel, RACH, procedure; obtaining information on the signal-to-noise ratio measured by the user apparatus from of the signal received by the user apparatus and Timing Advance required on the radio connection; transmitting a Radio Resource Control, RRC, release message with a redirection to other cell of the two ad hoc cells in the radio connection to the user apparatus, repeating the above obtaining and transmitting steps a given number of times; determining the location of the user apparatus based on the obtained information.
16. The non-transitory computer-readable medium of claim 15 , wherein the main lobes of the directional antennas of the second cell are perpendicular to each other.
17. The non-transitory computer-readable medium of claim 16 , wherein the second cell of the ad hoc cells utilizes four directional or beamforming antennas each providing a main lobe on the same horizontal plane and perpendicular to each other and a fifth directional antenna, the main lobe of the fifth antenna being perpendicular to the main lobes of the four other directional or beamforming antennas.
18. The non-transitory computer-readable medium of claim 15 , further comprising:
transmitting the Radio Resource Control, RRC, release message with a redirection to the first cell, if the user apparatus is being served by the second cell; and
transmitting the Radio Resource Control, RRC, release message with a redirection to the second cell, if the user apparatus is being served by the first cell, wherein the second cell is configured to activate a directional or beamforming antenna which did not serve the user apparatus before transferring the user apparatus to the first cell.
19. The non-transitory computer-readable medium of claim 15 , further comprising:
determining a vector for two or more directional or beamforming antennas of the set of directional or beamforming antennas, the direction of the vector corresponding to the direction of the main lobe of the directional or beamforming antenna and the length of the vector corresponding to the signal-to-noise ratio measured by the user apparatus when being in radio connection utilizing the directional or beamforming antenna;
determining the location of the user apparatus based on the sum of the vectors.
20. The non-transitory computer-readable medium of claim 15 , further comprising:
activating the directional or beamforming antennas in the second cell one by one at a time in a given order.