Patent Description:
An ad hoc radio base station implements an ad hoc (created for a particular purpose as necessary) cell to operate in parallel with existing (usually permanent) cells. The ad hoc radio base station may be used in a surveillance operation, for example. As pre-planning of the ad hoc cell may not be possible, and co-operation with existing cellular radio network infrastructure may be minimal, operation of the ad hoc radio base station needs to be sophisticated to enable flexible and easy operation. <CIT>, for example, discloses a method for determining a direction of a mobile communication device using a separately introduced base station.

<CIT> discloses a network autonomous wireless location system, <CIT> discloses a geographical detection of mobile terminals, <CIT> discloses identification of mobile phones; <CIT> discloses determining number of people in an area, <CIT> discloses detection of surveillance device and <CIT> discloses a system for phone privacy.

According to an aspect, there is provided subject matter of independent claims. Dependent claims define some embodiments.

One or more examples of implementations are set forth in more detail in the accompanying drawings and the description of embodiments.

Some embodiments will now be described with reference to the accompanying drawings, in which.

Reference numbers, both in the description of the embodiments and in the claims, serve to illustrate the embodiments with reference to the drawings, without limiting it to these examples only.

The embodiments and features, if any, disclosed in the following description that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

Let us study <FIG>, which illustrates embodiments of an ad hoc radio base station <NUM>, <FIG>, <FIG>, and <FIG>, which illustrate an implementation of successive ad hoc cells <NUM>+<NUM> and <NUM>+<NUM> using the ad hoc radio base station <NUM>, and <FIG> and <FIG>, which illustrate embodiments of a method for implementing the two successive ad hoc cells <NUM>+<NUM> and <NUM>+<NUM>.

An existing Long-Term Evolution (LTE) cellular radio network <NUM> is already in place and operating. The LTE cellular radio network <NUM> comprises one or more radio base stations <NUM>, <NUM>. Each radio base station <NUM>, <NUM> provides an access for LTE user apparatuses <NUM> residing in a cell <NUM>, <NUM> maintained by the radio base station <NUM>, <NUM> to utilize communication resources of the LTE cellular radio network <NUM>. The LTE cellular radio network <NUM> also comprises a core network <NUM> with numerous network elements. The radio base station (BS) <NUM>, <NUM> may also be known as a base transceiver station (BTS), an access point (AP), or an eNodeB (eNB), for example.

The radio base station <NUM>, <NUM> operates according to LTE technology, sometimes referred to as a fourth generation (<NUM>), defined in numerous telecom standard specifications.

The LTE user apparatus <NUM> may also be known as a user equipment (UE), a radio terminal, a subscriber terminal, a smartphone, a mobile station, a mobile phone, a portable computer, a tablet computer, a smartwatch, smartglasses, a game terminal, a machine-type communication (MTC) apparatus, an IoT (Internet of Things) apparatus, a sensor apparatus, or some other type of wireless mobile communication device operating with or without a subscriber identification module (SIM) or an eSIM (embedded SIM). The LTE user apparatus <NUM> may be a device that is configured to associate the LTE user apparatus <NUM> and its user with a subscription and allows the user to interact with the LTE cellular radio network <NUM>, i.e., the LTE user apparatus <NUM> is capable of requesting service from the LTE cellular radio network <NUM>. The LTE user apparatus <NUM> may present information to the user and allow the user to input information. In other words, the LTE user apparatus <NUM> may be any user apparatus capable of wirelessly receiving information from and/or wirelessly transmitting information to the LTE cellular radio network <NUM>. Besides communication capabilities, the LTE user apparatus <NUM> may include computer functionalities, functionalities of other data processing devices, and/or one or more sensors.

The ad hoc radio base station <NUM> implements two successive ad hoc LTE cells <NUM>+<NUM> and <NUM>+<NUM> to operate in parallel with the existing LTE cells <NUM>, <NUM>. The ad hoc radio base station <NUM> may be used in a surveillance operation (such as in communications intelligence, or COMINT) to gather information regarding the user apparatus <NUM>. In other words, the main reason to add the ad hoc radio base station <NUM> to an area is to get LTE user apparatuses <NUM> to connect to the ad hoc radio base station <NUM>.

The ad hoc radio base station <NUM> comprises one or more radio transceivers <NUM> configured to receive and transmit in the LTE cellular radio network <NUM>, and means for causing performance of the ad hoc radio base station <NUM>. In an embodiment, the means comprise one or more processors <NUM>.

In an embodiment illustrated in <FIG>, the one or more processors <NUM> comprise one or more memories <NUM> including computer program code <NUM>, and one or more microprocessors <NUM> configured to execute the computer program code <NUM> to cause the performance of the ad hoc radio base station <NUM>.

In an alternative embodiment, the means comprise a circuitry configured to cause the performance of the ad hoc radio base station <NUM>.

A non-exhaustive list of implementation techniques for the one or more microprocessors <NUM> and the one or more memories <NUM>, or the circuitry includes, but is not limited to: logic components, standard integrated circuits, application-specific integrated circuits (ASIC), system-on-a-chip (SoC), application-specific standard products (ASSP), microprocessors, microcontrollers, digital signal processors, special-purpose computer chips, field-programmable gate arrays (FPGA), and other suitable electronics structures.

The term 'memory' <NUM> refers to a device that is capable of storing data run-time (= working memory) or permanently (= non-volatile memory). The working memory and the non-volatile memory may be implemented by a random-access memory (RAM), dynamic RAM (DRAM), static RAM (SRAM), a flash memory, a solid state disk (SSD), PROM (programmable read-only memory), a suitable semiconductor, or any other means of implementing an electrical computer memory.

The computer program code (or software) <NUM> may be written by a suitable programming language (such as C, C++, assembler, or machine language, for example), and the resulting executable code may be stored in the one or more memories <NUM> and run by the one or more microprocessors <NUM>. The computer program code implements the method/algorithm illustrated in <FIG> and <FIG>. The computer program code <NUM> may be stored in a source code form, object code form, executable form, or in some intermediate form, but for use in the one or more microprocessors <NUM> it is in the executable form. There are many ways to structure the computer program code <NUM>: the operations may be divided into modules, sub-routines, methods, classes, objects, applets, macros, etc., depending on the software design methodology and the programming language used. In modern programming environments, there are software libraries, i.e., compilations of ready-made functions, which may be utilized by the computer program code <NUM> for performing a wide variety of standard operations. In addition, an operating system (such as a general-purpose operating system or a real-time operating system) may provide the computer program code <NUM> with system services.

An embodiment provides a computer-readable medium <NUM> storing the computer program code <NUM>, which, when loaded into the one or more microprocessors <NUM> and executed by the one or more microprocessors <NUM>, causes the performance of the computer-implemented method/algorithm. The computer-readable medium <NUM> may comprise at least the following: any entity or device capable of carrying the computer program code <NUM> to the one or more microprocessors <NUM>, a record medium, a computer memory, a read-only memory, an electrical carrier signal, a telecommunications signal, and a software distribution medium. In some jurisdictions, depending on the legislation and the patent practice, the computer-readable medium <NUM> may not be the telecommunications signal. In an embodiment, the computer-readable medium <NUM> is a computer-readable storage medium. In an embodiment, the computer-readable medium <NUM> is a non-transitory computer-readable storage medium.

Now that the structure of the ad hoc radio base station <NUM> and its operating environment have been described, let us study the dynamics of the method/algorithm with reference to <FIG> for the main sequence, and <FIG> illustrating optional embodiments. The method starts in <NUM> and ends in <NUM>. The operations are not strictly in chronological order and some of the operations may be performed simultaneously or in an order differing from the given ones. Other functions may also be executed between the operations or within the operations and other data exchanged between the operations. Some of the operations or part of the operations may also be left out or replaced by a corresponding operation or part of the operation. It should be noted that no special order of operations is required, except where necessary due to the logical requirements for the processing order.

<FIG> illustrates a first operation phase, wherein the ad hoc radio base station <NUM> is preparing for the actual operation.

First, information regarding the existing LTE cells <NUM>, <NUM> is obtained. The ad hoc radio base station <NUM> may either comprise a radio scanner (possibly utilizing the one or more radio transceivers <NUM>) to scan a predetermined radio spectrum to generate the information, or the ad hoc radio base station <NUM> may receive the information from an external radio scanner. The information may at least partly be obtained by receiving <NUM>, <NUM> system information from the existing LTE cells <NUM>, <NUM>. The information may include SIB1 (SystemInformationBlockType1). The ad hoc radio base station <NUM> may retrieve <NUM> at least a part of the information from an internal or external data source <NUM>, such as from an internal or external database.

<FIG> illustrates a second operation phase, wherein the ad hoc radio base station <NUM> sets up the ad hoc LTE cell <NUM>+<NUM>.

In <NUM>, the ad hoc LTE cell <NUM>+<NUM> is set up on a channel number with a Physical Cell ID (PCID), and a Tracking Area Code (TAC). The channel number may be selected such that it is not in use in the adjacent existing LTE cells <NUM>, <NUM>.

In an embodiment, the channel number is defined as an E-UTRA Absolute Radio Frequency Channel Number (EARFCN). EARFCN may be an integer in a range from <NUM> to <NUM>.

<FIG> also illustrates a third operation phase, wherein the ad hoc LTE cell <NUM>+<NUM> starts to serve the LTE user apparatus <NUM>. Instead of providing full service with data and/or speech transmission, the ad hoc LTE cell <NUM>+<NUM> keeps the LTE user apparatus <NUM> connected so that appropriate surveillance operations may be performed. As shown in <FIG>, the LTE user apparatus <NUM> may receive transmissions <NUM>, <NUM> from the existing LTE base stations <NUM>, <NUM>, but a transmission <NUM> from the ad hoc LTE base station <NUM> is received with a higher power and/or a better quality at the LTE user apparatus <NUM>, which causes that the LTE user apparatus <NUM> connects <NUM> to the ad hoc LTE base station <NUM>.

In <NUM>, a radio connection <NUM>, <NUM> is set up in the ad hoc LTE cell <NUM>+<NUM> to the LTE user apparatus <NUM> using a Random Access Channel (RACH) procedure. In an embodiment, a transmission power of the ad hoc LTE cell <NUM>+<NUM> is set such that LTE user apparatuses <NUM> residing in the ad hoc LTE cell <NUM>+<NUM> inevitably connect to the ad hoc LTE cell <NUM>+<NUM> (instead of the LTE cells <NUM>, <NUM> of the existing cellular radio network <NUM>).

In <NUM>, a Non-Access Stratum (NAS) timer is set simultaneously with the setting up of the radio connection <NUM>, <NUM>. In an embodiment, the NAS timer is T3411, which is specified in standard 3GPP <NUM>, and whose length (or duration) is <NUM> seconds. The NAS timer may be set in <NUM> simultaneously with a setting of a NAS timer in the LTE user apparatus <NUM>. In this way, the ad hoc base station <NUM> is able to act before the NAS timer expires in the LTE user apparatus <NUM>. As the ad hoc base station <NUM> knows when the radio connection is set up <NUM>, <NUM>, the NAS timer may be set in the ad hoc base station <NUM> with an adequate precision to coincide with the setting of the NAS timer in the LTE user apparatus <NUM>.

In <NUM>, the following operations <NUM>-<NUM>-<NUM> are repeated until a predetermined period of time remains before an expiry of the NAS timer. The predetermined period of time may vary in length.

For example, if the length of the NAS timer is <NUM> seconds, the predetermined period of time may be <NUM>-<NUM> seconds, taking into account that the NAS timer may be set in the ad hoc base station <NUM> a little bit later than the NAS timer is set in the LTE user apparatus <NUM>. Furthermore, enough time need to be reserved for the operations performed during the predetermined period of time before the expiry of the NAS timer.

However, the predetermined period of time may also be <NUM>-<NUM> seconds, especially if the "ping-pong" (= switching) between the successive ad hoc cells <NUM>+<NUM> and <NUM>+<NUM> is kept fast. In this way, the LTE user apparatus <NUM> keeps on transmitting in the uplink <NUM> with a relatively high transmission power, because otherwise the transmission power in the uplink <NUM> is being gradually lowered after the RACH procedure.

In <NUM>, the LTE user apparatus <NUM> is commanded with a Medium Access Control (MAC) control message in the radio connection <NUM> to use full buffer in all uplink messages of the radio connection <NUM>.

In <NUM>, the LTE user apparatus <NUM> is forced to send uplink messages in the radio connection <NUM> by sending to the LTE user apparatus <NUM> one of a Radio Resource Control User Equipment (RRC UE) capability request message, an NAS identity request message, or an NAS security mode command message.

In <NUM>, a reply message is received in the radio connection <NUM> from the LTE user apparatus <NUM>.

In <NUM>, during the predetermined period of time <NUM> before the expiry of the NAS timer, the ad hoc LTE cell <NUM>+<NUM> is restarted on the channel number with a different PCID, and a different TAC than in the previous radio connection.

<FIG> illustrates this fourth operation phase, wherein the ad hoc LTE cell <NUM>+<NUM> continues the serving of the LTE user apparatus <NUM>.

Performance is continued from the setting up in <NUM> of the radio connection <NUM>, <NUM> in the ad hoc LTE cell <NUM>+<NUM> to the LTE user apparatus <NUM> using the RACH procedure.

The sequence <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM> is performed before an integrity protection is activated and may be continued as long as needed to keep the LTE user apparatus <NUM> connected to the successive ad hoc LTE cells <NUM>+<NUM> and <NUM>+<NUM>. During the connection, a direction finding of the LTE user apparatus <NUM> may be performed. One part of the direction finding is to calculate a distance estimate from the ad hoc radio base station <NUM> to the LTE user apparatus <NUM>.

In an embodiment, the ad hoc LTE cell <NUM>+<NUM> is set up in <NUM> on the channel number using also a Global Cell ID (GCID), and the ad hoc LTE cell <NUM>+<NUM> is restarted in <NUM> on the channel number also with a different GCID than in the previous radio connection.

In an embodiment, during the predetermined period of time <NUM> before the expiry of the NAS timer, and before restarting in <NUM> the ad hoc LTE cell <NUM>+<NUM> / <NUM>+<NUM> on the channel number with the different PCID, and the different TAC than in the previous radio connection, an NAS reject message with a network failure or congestion as the cause is transmitted in <NUM> in the radio connection <NUM>/<NUM> to the LTE user apparatus <NUM>.

In an embodiment, after receiving the reply message in the radio connection <NUM>/<NUM> from the LTE user apparatus <NUM> in <NUM>, a distance estimate to the LTE user apparatus <NUM> is calculated in <NUM> based on a current uplink timing advance value of the radio connection <NUM>. Note that the distance estimate to the LTE user apparatus <NUM> may also be calculated in <NUM> as a first operation within the repeat loop <NUM> based on a current uplink timing advance value of the radio connection <NUM>.

In an embodiment, after receiving the reply message in the radio connection <NUM>/<NUM> from the LTE user apparatus <NUM> in <NUM>, it is checked in <NUM> whether a predetermined amount of time starting from a previous RACH procedure has passed during the predetermined period of time. The predetermined period of time may be kept relatively short, but also long enough so that state machines of communications protocols operating within the LTE user apparatus <NUM> do not malfunction or even crash. The predetermined period of time may be about one second, for example. If the predetermined amount of time has passed (the test in <NUM> evaluates "YES"), a Layer <NUM> Physical Downlink Control Channel (L1 PDCCH) order message is transmitted in <NUM> in the radio connection <NUM>/<NUM> to the LTE user apparatus <NUM>, and a new RACH procedure with the LTE user apparatus <NUM> is performed in <NUM> to set up the radio connection <NUM>, <NUM> / <NUM>, <NUM> in the ad hoc LTE cell <NUM>+<NUM> / <NUM>+<NUM> to the LTE user apparatus <NUM>. In an embodiment, a distance estimate to the LTE user apparatus <NUM> is calculated based on the new RACH procedure setting up the radio connection <NUM>, <NUM> / <NUM>, <NUM>. In addition to the calculation of the distance estimate, a more general direction finding of the LTE user apparatus <NUM> may be performed based on parameters obtained during the new RACH procedure. One way to perform the direction finding is to move the ad hoc base station <NUM> between successive distance estimates to the LTE user apparatus <NUM>. The successive distance estimates may be defined as circles around the ad hoc base station <NUM>, and an intersection area of the circles may be calculated as a target area, wherein the LTE user apparatus <NUM> is residing. In an embodiment, a special portable direction finding apparatus <NUM> may be used: as shown in <FIG> and <FIG>, the apparatus <NUM> is instructed to receive and measure the uplink transmissions <NUM>, <NUM> from the LTE user apparatus <NUM>, whereby the apparatus <NUM> may estimate the direction to the LTE user apparatus <NUM>. As explained earlier, the use of the high transmission power in the uplink <NUM>, <NUM> improves the direction finding operation of the apparatus <NUM> in relation to the LTE user apparatus <NUM>. In an embodiment, a variable attenuator <NUM> may be placed in the ad hoc base station <NUM> in the line between an antenna (not illustrated in <FIG>) and the one or more radio transceivers <NUM>. If the received uplink signal <NUM>, <NUM> is attenuated in the ad hoc base station <NUM> before its processing, the LTE user apparatus <NUM> is forced to use more transmission power.

Let us next study <FIG>, which illustrates embodiments of a system <NUM> comprising a first ad hoc radio base station 100A and a second ad hoc radio base station 100B, <FIG>, and <FIG>, which illustrate an implementation of two simultaneous ad hoc cells 120A, 120B using the first ad hoc radio base station 100A and the second ad hoc radio base station 100B, and <FIG> and <FIG>, which illustrate embodiments of a method for implementing the two simultaneous ad hoc cells 120A, 120B.

As was explained earlier, the single ad hoc radio base station <NUM> implements two successive ad hoc cells <NUM>+<NUM> and <NUM>+<NUM> in a non-ending loop, whereby the LTE user apparatus <NUM> is kept being connected to the ad hoc cells <NUM>+<NUM> and <NUM>+<NUM> in succession. The system <NUM> with the two ad hoc radio base stations 100A, 100B implements two simultaneous ad hoc cells 120A, 120B, whereby the LTE user apparatus <NUM> is kept being connected to the simultaneous ad hoc cells 120A and 120B in succession.

The first ad hoc radio base station 100A and the second ad hoc radio base station 100B may have similar structure as the earlier described ad hoc radio base station <NUM>, except the executed method/algorithm is naturally different. Consequently, the two ad hoc radio base stations 100A, 100B comprise one or more radio transceivers 102A, 102B and one or more processors 104A, 104B. The other reference signs 106A, 108A, 110A, 112A, 114A, 116A, 130A, 106B, 108B, 110B, 112B, 114B, 116B, and 130B also correspond to the earlier described <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

Let us study the dynamics of the method/algorithm with reference to <FIG> for the main sequence, and <FIG> illustrating optional embodiments. The method starts in <NUM> and ends in <NUM>.

As shown in <FIG>, the operations are divided between the operations <NUM>-<NUM> of the first ad hoc base station 100A on the left side, and the operations <NUM>-<NUM> of the second ad hoc base station 100B on the right side.

The first operation phase, wherein the ad hoc radio base stations 100A, 100B are preparing for the actual operation is not repeated here as it basically corresponds to that described with reference to <FIG>.

<FIG> illustrates a second operation phase, wherein the ad hoc radio base stations 100A, 100B set up the simultaneous ad hoc LTE cells 120A, 120B.

In <NUM>, the first ad hoc radio base station 100A sets up a first ad hoc LTE cell 120A on a first channel number with a first TAC.

In <NUM>, the second ad hoc radio base station 100B sets up a second ad hoc LTE cell 120B on a second channel number with a second TAC. Note that the PCID may be the same or different for the first and second ad hoc LTE cells 120A, 120B, because the cells 120A, 120B are on different frequencies.

In an embodiment, the operations <NUM> and <NUM> are performed simultaneously so that the first ad hoc LTE cell 120A and the second ad hoc LTE cell 120B coexist.

The first channel number and the second channel number may be selected such that they are not in use in the adjacent existing LTE cells <NUM>, <NUM>.

In an embodiment, the first channel number is defined as a first EARFCN, and the second channel number is defined as a second EARFCN.

<FIG> also illustrates a third operation phase, wherein the first ad hoc LTE cell 120A starts to serve the LTE user apparatus <NUM>. Instead of providing full service with data and/or speech transmission, the first ad hoc LTE cell 120A keeps the LTE user apparatus <NUM> connected so that appropriate surveillance operations may be performed. As shown in <FIG>, the LTE user apparatus <NUM> may receive transmissions <NUM>, <NUM> from the existing LTE base stations <NUM>, <NUM>, but a transmission <NUM> from the first ad hoc LTE base station 100A is received with a higher power and/or a better quality at the LTE user apparatus <NUM>, which causes that the LTE user apparatus <NUM> connects <NUM> to the first ad hoc LTE base station 100A.

In <NUM>, the first ad hoc radio base station 100A, sets up a first radio connection <NUM>, <NUM> in the first ad hoc LTE cell 120A to an LTE user apparatus <NUM> using a first RACH procedure. In an embodiment, a transmission power of the first ad hoc LTE cell 120A is set such that LTE user apparatuses <NUM> residing in the first ad hoc LTE cell 120A inevitably connect to the first ad hoc LTE cell 120A (instead of the LTE cells <NUM>, <NUM> of the existing cellular radio network <NUM>, and instead of the second ad hoc LTE cell 120B).

In <NUM>, the first ad hoc radio base station 100A transmits an RRC release message with a redirection to the second ad hoc LTE cell 120B in the first radio connection <NUM> to the LTE user apparatus <NUM>.

In <NUM>, the second ad hoc radio base station 100B sets up a second radio connection <NUM>, <NUM> in the second ad hoc LTE cell 120B to the LTE user apparatus <NUM> using a second RACH procedure, because the first ad hoc LTE cell 120A transmitted the RRC release message with the redirection to the second ad hoc LTE cell 120B to the LTE user apparatus <NUM>.

<FIG> illustrates this fourth operation phase, wherein the second ad hoc LTE cell 120B continues the serving of the LTE user apparatus <NUM>.

In <NUM>, the second ad hoc radio base station 100B sets a NAS timer simultaneously with the setting up of the second radio connection <NUM>, <NUM>. In an embodiment, the NAS timer is set in <NUM> simultaneously with a setting of a NAS timer in the LTE user apparatus <NUM>.

In <NUM>, the second ad hoc radio base station 100B repeats the operations <NUM>-<NUM> until a predetermined period of time remains before an expiry of the NAS timer. An optional operation may be performed in <NUM> at the start of the sequence.

In an embodiment of <NUM>, the second ad hoc radio base station 100B commands with a MAC control message in the second radio connection <NUM> the LTE user apparatus <NUM> to use full buffer in all uplink messages of the second radio connection <NUM>.

In <NUM>, the second ad hoc radio base station 100B forces the LTE user apparatus <NUM> to send uplink messages in the second radio connection <NUM> by sending to the LTE user apparatus <NUM> one of a Radio Resource Control User Equipment, RRC UE, capability request message, an NAS identity request message, or an NAS security mode command message.

In <NUM>, the second ad hoc radio base station 100B receives a reply message in the second radio connection <NUM> from the LTE user apparatus <NUM>.

In <NUM>, during, the predetermined period of time <NUM> before the expiry of the NAS timer, the second ad hoc radio base station 100B transmits an RRC release message with a redirection to the first ad hoc LTE cell 120A in the second radio connection <NUM> to the LTE user apparatus <NUM>.

After <NUM>, the first ad hoc radio base station 100A continues performance from the setting up of the first radio connection <NUM>, <NUM> in the first ad hoc LTE cell 120A to the LTE user apparatus <NUM> using the first RACH procedure in <NUM>.

The sequence <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM> may be continued as long as needed to keep the LTE user apparatus <NUM> connected to the simultaneous ad hoc LTE cells 120A and 120B in turns.

In an embodiment, the first ad hoc LTE cell 120A is set up in <NUM> on the first channel number using also a first GCID, and the second ad hoc LTE cell 120B is set up in <NUM> on the second channel number using also a second GCID.

In an embodiment, during the predetermined period of time <NUM> before the expiry of the NAS timer, and before transmitting the RRC release message with the redirection to the first ad hoc LTE cell 120A in the second radio connection <NUM> to the LTE user apparatus <NUM> in <NUM>, the second ad hoc base station 100B transmits in <NUM> an NAS reject message with a network failure or congestion as the cause in the second radio connection <NUM> to the LTE user apparatus <NUM>.

In an embodiment, after the second ad hoc base station 100B receives the reply message in the second radio connection <NUM> from the LTE user apparatus <NUM> in <NUM>, the second ad hoc base station 100B calculates in <NUM> a distance estimate to the LTE user apparatus <NUM> based on a current uplink timing advance value of the second radio connection <NUM>. Note that the second ad hoc base station 100B may also calculate in <NUM> a distance estimate to the LTE user apparatus <NUM> as a first operation within the repeat loop <NUM> based on a current uplink timing advance value of the radio connection <NUM>.

In an embodiment, after the second ad hoc base station 100B receives the reply message in the second radio connection <NUM> from the LTE user apparatus <NUM> in <NUM>, the second ad hoc base station 100B checks in <NUM> whether a predetermined amount of time starting from a previous RACH procedure has passed during the predetermined period of time. If the predetermined amount of time has passed (the test in <NUM> evaluates "YES"), the second ad hoc base station 100B transmits in <NUM> an L1 PDCCH order message in the radio connection <NUM> to the LTE user apparatus <NUM>, and a new RACH procedure with the LTE user apparatus <NUM> is performed in <NUM> to set up the second radio connection <NUM>, <NUM> in the second ad hoc LTE cell 120B to the LTE user apparatus <NUM>. In an embodiment, a distance estimate to the LTE user apparatus <NUM> is calculated based on the new RACH procedure setting up the second radio connection <NUM>, <NUM>.

It will be appreciated that some embodiments described herein may include one or more generic or specialized processors ("one or more processors") such as microprocessors; central processing units (CPUs); digital signal processors (DSPs): customized processors such as network processors (NPs) or network processing units (NPUs), graphics processing units (GPUs), or the like; field programmable gate arrays (FPGAs); and the like along with unique stored program instructions (including both software and firmware) for control thereof to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more application-specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic or circuitry. Of course, a combination of the aforementioned approaches may be used. For some of the embodiments described herein, a corresponding device in hardware and optionally with software, firmware, and a combination thereof can be referred to as "circuitry configured or adapted to," "logic configured or adapted to," etc. perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. on digital and/or analog signals as described herein for the various embodiments.

Claim 1:
An ad hoc radio base station (<NUM>), comprising:
one or more radio transceivers (<NUM>) configured to receive and transmit in a Long-Term Evolution, LTE, cellular radio network; and
means (<NUM>) for:
setting (<NUM>) up an ad hoc LTE cell on a channel number with a Physical Cell ID, PCID, and a Tracking Area Code, TAC;
setting (<NUM>) up a radio connection in the ad hoc LTE cell to an LTE user apparatus using a Random Access Channel, RACH, procedure;
setting (<NUM>) a Non-Access Stratum, NAS, timer simultaneously with the setting up of the radio connection; characterized by
repeating (<NUM>) the following three steps until a predetermined period of time remains before an expiry of the NAS timer:
commanding (<NUM>) with a Medium Access Control, MAC, control message in the radio connection the LTE user apparatus to use full buffer in all uplink messages of the radio connection;
forcing (<NUM>) the LTE user apparatus to send uplink messages in the radio connection by sending to the LTE user apparatus one of a Radio Resource Control User Equipment, RRC UE, capability request message, an NAS identity request message, or an NAS security mode command message; and
receiving (<NUM>) a reply message to the one of a Radio Resource Control User Equipment (RRC UE) capability request message, an NAS identity request message, or an NAS security mode command message in the radio connection from the LTE user apparatus;
during (<NUM>) the predetermined period of time before the expiry of the NAS timer:
restarting (<NUM>) the ad hoc LTE cell on the channel number with a different PCID, and a different TAC than in the previous radio connection; and
continuing performance from the setting (<NUM>) up of the radio connection with the different PCID, and the different TAC in the ad hoc LTE cell to the LTE user apparatus using the RACH procedure.