DEVICES AND METHODS FOR DETERMINING A POSITION OF A MOBILE TERMINAL

Abstract

The present invention relates to devices and methods for determining a position of a mobile terminal with assistance from a wireless communication system. The mobile terminal is configured to receive a reference signal from a reference point of the wireless communication system, to receive positioning assistance information related to the reference point, and to determine its position based on the positioning assistance information and the reference signal.

Claims

1. A mobile terminal for a wireless communication system, the mobile terminal comprising: at least one processor, wherein the at least one processor is configured to execute a computer program stored in a memory so as to perform a method comprising: receiving a reference signal from a reference point of the wireless communication system, receiving positioning assistance information related to the reference point, and determining a position of the mobile terminal based on the positioning assistance information and the reference signal.

2. The mobile terminal according to claim 1, wherein the positioning assistance information comprises antenna configuration information of the reference point and/or geometry-related information of the reference point.

3. The mobile terminal according to claim 2, wherein the antenna configuration information includes at least one of the group consisting of: an antenna orientation, a beam configuration, and calibration and/or installation errors of the reference point.

4. The mobile terminal according to claim 2, wherein the geometry-related information includes a height and/or global coordinates of the reference point.

5. The mobile terminal according to claim 2, wherein the positioning assistance information further comprises scheduling-related information including transmission sub-frames and/or update periodicity and/or resource mappings.

6. The mobile terminal according to claim 1, the method further comprising determining angle-related information of the reference signal and determining the position of the mobile terminal based on the angle-related information and the positioning assistance information, wherein the angle-related information is based on an Angle of Departure (AoD) measurement and/or an Angle of Arrival (AoA) measurement.

7. The mobile terminal according to claim 1, the method further comprising: determining time-related information of the reference signal, and determining the position of the mobile terminal based on the time-related information and the positioning assistance information, wherein the time-related information is determined by performing a Time of Arrival (TOA) measurement and/or a Time Difference of Arrival (TDOA) measurement.

8. The mobile terminal according to claim 1, the method further comprising: requesting and/or receiving the positioning assistance information from the wireless communication system.

9. The mobile terminal according to claim 1, the method further comprising: determining a coarse position of the mobile terminal without the positioning assistance information and the reference signal, determining a region of interest (ROI) based on the coarse position, and reporting an information about the ROI to the wireless communication system.

10. The mobile terminal according to claim 9, wherein the ROI is based on a distance to at least one further mobile terminal.

11. A location server for a wireless communication system, comprising: at least one processor, wherein the processor is configured to execute a computer program stored in a memory so as to perform a method comprising: determining positioning assistance information to be sent to a mobile terminal, wherein the positioning assistance information enables the mobile terminal to determine its position based on the positioning assistance information and a reference signal received from a reference point of the wireless communication system, wherein the positioning assistance information is related to the reference point.

12. The location server according to claim 11, the method further comprising: determining positioning assistance information for the mobile terminal and/or an updating period of the positioning assistance information based on at least one of the group consisting of: a request of the mobile terminal, an estimated coarse position of the mobile terminal, a determined position of the mobile terminal, and an expected trajectory of the mobile terminal.

13. The location server according to claim 11, the method further comprising: requesting assistance information from a transmitter transmitting the positioning assistance information and/or from one or more reference points transmitting one or more reference signals, receiving the assistance information from the transmitter and/or the reference points, and determining the positioning assistance information for the mobile terminal based on the received assistance information.

14. The location server according to any of claim 11, the method further comprising: grouping a number of mobile terminals into groups according to the course positions of the mobile terminals, and determining, for each respective group of mobile terminals, the same positioning assistance information to be multicast to the mobile terminals comprised in the corresponding group, and changing the grouping when the mobile terminals have changed positions.

15. A base station for a wireless communication system, comprising: at least one processor, wherein the processor is configured to execute a computer program stored in a memory so as to execute a method comprising: receiving positioning assistance information to be sent to a mobile terminal in order to enable the mobile terminal to determine a position of the mobile terminal based on the received positioning assistance information and a reference signal received from a reference point of the wireless communication system, and transmitting the positioning assistance information to the mobile terminal, wherein the positioning assistance information is related to the reference point.

16. The base station according to claim 15, the method further comprising transmitting the reference signal.

17. The base station according to claim 15, the method further comprising: broadcasting the positioning assistance information to multiple mobile terminals within one or more Regions of Interest (RoI), and/or multicasting the positioning assistance information to multiple mobile terminals, and/or unicasting the positioning assistance information to a single mobile terminal.

18. The base station according to any of claim 15, the method further comprising transmitting the positioning assistance information using beamforming based on at least one of the group consisting of: a coarse position of a mobile terminal, a region of interest, and a content of the positioning assistance information.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0155] FIG. 1 is a schematic block diagram showing a wireless communication system and a mobile terminal according to an embodiment.

[0156] FIGS. 2a to 2d show steps of a method for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment.

[0157] FIGS. 3a and 3b show alternate scenarios for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment.

[0158] FIG. 4 shows another scenario for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment.

[0159] FIGS. 5a and 5b show further scenarios for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment.

[0160] FIGS. 6a and 6b show scenarios for determining a region of interest (RoI) and for signaling according to an embodiment.

DETAILED DESCRIPTION

[0161] In the following, embodiments are described with reference to the enclosed figures.

[0162] FIG. 1 is a schematic block diagram showing a general scheme of a wireless communication system 100 and a mobile terminal 110 according to an embodiment.

[0163] The mobile terminal 110 may be an user equipment (UE) such as a mobile phone used by a user, or any radio module able to send and receive signals to the or from the wireless communication system 100. Such a radio module acting as a mobile terminal may for example be provided at a sensor, a machine, a robot, a vehicle, a drone or the like. The mobile terminal 110 is configured to send a request 151 for positioning assistance information to the wireless communication system 100 and to receive the positioning assistance information 154 from the system.

[0164] The communication system 100 comprises a location server 120. The location server may be a dedicated server for the purpose of localization, or be implemented on another server comprised in the communication system 100. The functionality of the location server 120 may also be distributed over more than one server comprised in the communication system 100. In the following, the term location server designates the functional unit provided in the communication system 100 for the purpose of localization.

[0165] The wireless communication system 100 further comprises a base station 130 and one or more reference points 140a, 140b. The base 130 station is a transmitter/receiver capable to communicate with the mobile terminal 110. It may for example be a base station for any conventional or future network standard such as a base transceiver station for the Global System for Mobile Communications (GSM), a nodeB for the Universal Mobile Telecommunications System (UMTS), an enodeB for LTE or the like. The reference points 140a, 140b are transmitters capable to send reference signals 157a, 157b to the mobile terminal 110. As an example, two reference points 140a, 140b are shown in FIG. 1, but the present invention is not limited thereto. Any suited number of reference points may be provided. On the other hand, the base station 130 itself may act as a reference point sending a reference signal so that no additional reference point is required.

[0166] As an example, a heterogeneous network is considered wherein the base station 130 is a low-frequency base station operating in a low frequency range (LF) below 6 GHz, while the reference points are high-frequency transmitters operating in a high frequency range (HF) above 6 GHz. In this case, the mobile terminal 110 has to be suited for multi-link connectivity (LF/HF). The HF reference points may be HF base stations, millimeter wave transmit receive points (mmWave TRP), HF access points (AP), UE anchors or the like. However, the present invention is not restricted to the above example. The base station 130 may also be a HF base station, and/or the reference points may be LF base stations, transmit receive points and/or access points.

[0167] The access points and/or UE anchors might, for example, change their position, antenna orientation and configuration in order to better support the localization. Such changes must then be updated and shared by the wireless communication system in real-time in order to ensure that the positioning assistance information is always updated.

[0168] The mobile terminal 110 is configured to determine its position with assistance from the wireless communication system 100. For this purpose, it sends a request 151 for positioning assistance information to the wireless communication system 100. The request 151 is received by the base station 130 and forwarded to the location server 120.

[0169] The location server 120 determines a positioning assistance information 154 to be sent to the mobile terminal 110. This positioning assistance information is related to the reference point(s) 140a, 140b which is or are intended to transmit a reference signal 157a, 157b to the mobile terminal 110. This positioning assistance information may comprise antenna configuration information of the reference point and/or and geometry-related information of the reference point and/or scheduling-related information.

[0170] The antenna configuration information may include an antenna orientation, and/or a beam configuration, and/or calibration and/or installation errors of the reference point. The antenna orientation may be given by an elevation angle or a downtilt angle, for example 0-10 in steps of 0.5, and/or an azimuth angle, for example 0-180 in steps of 0.5. The beam configuration may be given by the number of beams per antenna port and/or the beamwidth or angular spread, for example at 3 dB, 10 dB etc., and/or the Angle of Departure (AoD) with respect to the local coordinate system of the reference point and/or the beam ID to antenna port mapping and or the beam ID to AoD mapping. The calibration and/or installation errors may be given by a calibration mismatch, for example in the range from 0.5 to 0.5, and/or an installation mismatch, for example in the range from 0.6 to 0.6.

[0171] The geometry-related information may include a height, and/or global position coordinates, and/or an estimated error in the global position coordinates of an antenna or an antenna array, for example a 2D antenna array, of the reference point. The height of the antenna or antenna array may be given in m or cm. The global position coordinates of the antenna or antenna array may be given as longitude and latitude. They may for example be coordinates obtained via a global navigation satellite system (GNSS). The estimated error in the global position coordinates may be given as a variance of GNSS position coordinates and/or as an estimated positioning error (EPE) of a GNSS receiver.

[0172] The scheduling-related information may include transmission subframes and/or a periodicity of transmission and/or resource mappings. The transmission subframes and periodicity may for example be given as (10n.sub.f+[n.sub.s/2].sub.PRS) mod T.sub.PRS=0, wherein n.sub.s is the system frame number, n.sub.f is the slot number within the radio frame, .sub.PRS is the subframe offset within the periodicity T.sub.PRS of the positioning reference signals (PRS). The resource mappings may for example be given as indices of the resource elements and/or resource blocks and/or orthogonal frequency-division multiplexing (OFDM) symbols containing the reference signals.

[0173] For determining the content of the positioning assistance information (PAI) 154, the location server 120 may, for instance, take into account a coarse location and/or moving trajectory of the requesting mobile terminal 110. The location server may request up-to-date assistance information 155, 156a, 156b from the relevant reference points 130 (if the base station acts as a reference point), 140a, 140b. The location server 120 may further determine how frequently such a PAI needs to be updated.

[0174] The location server 120 may also determine a transmission scheme for transmitting the positioning assistance information 154 from the base station 130 to the mobile terminal(s) 110, for example taking into account the coarse location and/or moving trajectory and/or the number and/or distribution of the requesting mobile terminal(s) 110. Alternately, the corresponding decision may also be made by the base station 130 itself.

[0175] Examples of transmission schemes for the PAI may include, among others: [0176] Broadcasting the PAI to multiple mobile terminals, if for instance, high accuracy positioning is a required service within a Region of Interest (RoI); [0177] Multicasting the PAI to multiple mobile terminals, if for instance, multiple mobile terminals within the RoI send a request for positioning assistance information; [0178] Unicasting the PAI to a single mobile terminal, if a specific positioning assistance information is requested by a single mobile terminal or mobility tracking is required.

[0179] The serving base station, usually a LF-base station, may transmit the PAI with a widebeam in order to cover the Rot The base station may also transmit the PAI using beamforming that is based on at least one of a coarse position of a mobile terminal, a ROI, a content of the PAI. By joint and/or separated beam sweeping, PAI may be transmitted together with other system information. A single frequency network may be used where all the base stations (preferably HF base stations) within the RoI send the PAI in a certain time slot.

[0180] Finally, the location server 120 transmits the PAI to the base station 130 which forwards the PAI 154 to the mobile terminals 110 according to a transmission scheme as described above. Further, each of the involved reference points sends a reference signal 157a, 157b.

[0181] The mobile terminal receives the positioning assistance information 154 and the reference signal(s) 157a, 157b. It then determines, in a device based manner, the position of the mobile terminal 110 based on the received positioning assistance information 154 and the received reference signal signal(s) 157a, 157b. It may then provide position information back to the wireless communication system 100, preferably to the location server 120. The position information may consist of the determined position of the mobile terminal 110 and the estimation quality.

[0182] The mobile terminal 110 may for example determine angle-related information of the reference signal 157a, 157b, and then determine its position based on the angle-related information and the positioning assistance information 154. In particular, the mobile terminal may determine the angle-related information based on an Angle of Departure (AoD) measurement and/or an Angle of Arrival (AoA) measurement.

[0183] Additionally or alternatively, the mobile terminal 110 may for example determine time-related information of the reference signal 157a, 157b, and then determine its position based on the time-related information and the positioning assistance information 154. In particular, the mobile terminal may perform a Time of Arrival (TOA) measurement and/or a Time Difference of Arrival (TDOA) measurement for determining the time-related information.

[0184] Any other known method for determining the position from the reference signals may be used.

[0185] With the devices and methods described above, it is possible, for example, to perform a network-assisted determination of the position of the mobile terminal in a wireless communication system in the mobile terminal itself, i.e. in a device-based manner, but in a network-enabled manner. In comparison with a fully network-based position determination, network resources may be saved, and the accuracy of the position determination may be improved. Further, the accuracy of the position determination may also be improved with regard to a conventional device-based position determination without assistance of the network, for example using a global navigation satellite system (GNSS).

[0186] The role of the wireless communication system is to provide precise positioning as-a-service which is a type of network-enabled device-based positioning: It relies on the network to provide positioning assistance information (network-enabled) to certain types of mobile terminal, which in turn use this information to estimate their own position locally (device-based). From a resource utilization point of view, the proposed positioning service is highly resource efficient. Several new use cases and applications are naturally suited for this type of network-enabled device-based positioning, for example drone navigation, robot localization etc.

[0187] In the following, embodiments are described which relate to different scenarios or implementation examples to which the general scheme of the invention as described above with reference to FIG. 1 can be applied. The embodiments are described under the context of a dual connectivity scenario where below-6 GHz base stations (LF BS) and mmWave transmit receive points (TRPs) are involved. Due to the propagation characteristics of the mmWave band signal, the signal tends to arrive from a line-of-sight path. This to some extent simplifies the positioning. However, the PAI transmission procedure described in the embodiments can be applied to other multi-link scenarios, such as heterogeneous network consisting of small cells and macro BSs.

[0188] FIGS. 2a to 2d show steps of a method for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment, wherein mmWave positioning is enabled by conventional cellular positioning.

[0189] Since mmWave TRPs allow higher bandwidth usage and deployment of large 2D antenna array, they offer great potential for improving positioning accuracy. However, due to the limited coverage and sensitivity to blockage, dual connectivity to a low frequency base station (LF BS) such as an eNodeB is usually recommended. In this embodiment, the positioning procedure is described using the mmWave TRPs as reference points.

[0190] A first step is shown in FIG. 2a. The mobile terminal 210 may estimate its position using conventional positioning techniques, e.g. GNSS. This coarse estimation is then reported to the network where the RoI can be determined. As an alternative, the coarse positioning estimation can also be done on the network side using a Observed Time Difference Of Arrival (OTDoA) and/or a Uplink-Time Difference of Arrival (UTDoA) measurement. This is indicated in FIG. 2a by time differences .sub.1, .sub.2, .sub.3 with regard to three LF BSs 230a, 230b, 230c. In this case, the position reporting is not necessary since the position is determined in the network itself.

[0191] A second step is shown in FIG. 2b. In the case that high accuracy positioning enhancement is desired, the mobile terminal 210 sends a request 251 for PAI which is received by the base station 230 and forwarded to the location server 220.

[0192] A third step is shown in FIG. 2c. Based on the RoI 260 determined in step 1, the location server 220 obtains the up-to-date configuration of the relevant mmWave TRPs, namely the reference points 240a and 240b. This information is conveyed as a PAI 254 to the requesting mobile terminal 210 via the base station 230 which is a LF eNodeB which has a broad coverage.

[0193] A fourth step is shown in FIG. 2d. The reference points 240a and 240b send reference signals 257a, 257b to the mobile terminal 210. Based on the received reference signals 257a, 257b and the received PAI 254, the mobile terminal 210 determines its position in the global coordinates using for example, an AoD and/or AoA measurement as described above.

[0194] FIGS. 3a and 3b show alternate scenarios for a method for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment of the invention, wherein positioning assistance information is transmitted under network-induced updates. Although the antenna/beam configuration and physical parameters of the reference points are typically static, the PAI sometimes needs to be updated.

[0195] FIG. 3a shows a scenario example similar to the one shown in FIG. 2b. An LF base station 330 having an LF coverage area 370 and three mmW TRPs as reference points 340a, 340b, 340c, each having a mmW coverage area 380a, 380b, 380c, are provided. Further, multiple mobile terminals are provided. Mobile terminal 310a is the one with a high accuracy positioning request. A first RoI 360a is determined for this mobile terminal 310a. Mobile terminals 310b, 310c are positioned within this first ROI 360a, mobile terminals 310d, 310e are positioned outside of it.

[0196] FIG. 3b shows a scenario example where a temporary high accuracy positioning enhanced area (second RoI 360b) is introduced in addition to the existing first RoI 360a. When a nomadic node 311a, 311b having a coverage area 390a, 390b is introduced, the location server will request for the precise 3D coordinates and antenna/beam settings of these network entities. The same applies if an UE anchor is activated. This information will then be broadcast by the LF BS 330 to all mobile terminals 310d, 310e, 310f, 310g within the second RoI 360b and allows the mobile terminals in the second RoI 360b to exploit the reference points in its surrounding and estimate their position more accurately. Under this circumstance, different PAI are provided to mobile terminals within the existing first RoI 360a and those in the second RoI 360b.

[0197] FIG. 4 shows another scenario example for a method for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment, wherein the mobile terminal is moving. Therefore, a PAI transmission strategy for mobility tracking is required. The mobile terminal in this scenario example is attached to a drone. The location server may determine the content and the transmission scheme of the PAI according to the terminal's mobility. Depending on a coarse location, moving direction and velocity of the drone, the location server may determine an updating period of the PAI. The location server may also predict the reference points which the mobile terminal might encounter in the future and include their information in the PAI.

[0198] An LF base station 430 having an LF coverage area 470 and four mmW TRPs as reference points 440a, 440b, 440c, 440d are provided. In a first location, the mobile terminal 410a sends a request for PAI. The request for PAI may contain the long-term trajectory of the mobile terminal 410a, including for example a direction of movement, a speed and/or coordinates of its current destination. The location server (not shown in the picture) predicts from drone's estimated moving trajectory or from the transmitted long-term trajectory that the relevant reference point for the PAI to be sent as a response to the request will be the mmW TRP 440b. The base station 430 sends a beam 480a to the mobile terminal 410a in the first location, thereby transmitting PAI including information relating to the reference point 440b. In a similar way, the base station 430 at a later time sends a beam 480b to the mobile terminal 410b which has now moved to a second location, thereby transmitting PAI including information relating to the reference point 440c. Some time later, the base station 430 sends a beam 480c to the mobile terminal 410c which has now moved to a third location, thereby transmitting PAI including information relating to the reference point 440c.

[0199] FIGS. 5a and 5b show another scenario example for a method for determining a position of the mobile terminal with the assistance of the wireless communication system according to an embodiment of the invention, wherein the PAI is transmitted by multicasting based on a region of interest (RoI), especially in a dynamic environment wherein the mobile terminals are moving.

[0200] When multiple mobile terminals request for high accuracy positioning assistance, PAI can be transmitted to a group of mobile terminals within the RoI by multicasting. For multicast group, the PAI consists of the information on the mmW TRPs required for the particular group of UEs. In case that the distribution of mobile terminals is changed, the multicast grouping as well as the corresponding PAI of interest needs to be updated.

[0201] FIG. 5a shows a scenario example at a first time. An LF base station 530 having an LF coverage area 570 and five mmW TRPs as reference points 540a-540e, each having a mmW coverage area 580a-580e, are provided. Further, multiple mobile terminals 510a-510e and a nomadic node 511 are provided.

[0202] Depending on their position, the mobile terminals 510a-510e and the nomadic node 511 are grouped into two multicast groups. This may, for example, be performed by the location server (not shown in the figure). A first multicast group comprises the mobile terminals 510a-510c, a second the mobile terminals 510d, 510e and the nomadic node 511. The LF BS 530 sends a first beam 560a, thereby multicasting PAI including information relating to the reference points 540a-540c to the first multicast group, and a second beam 560b, thereby multicasting PAI including information relating to the reference points 540d, 540e to the second multicast group.

[0203] FIG. 5b shows the scenario example of FIG. 5a at a later time. Most of the mobile terminals 510a-510e and the nomadic node 511 have changed their position. Therefore, both the content and the transmission scheme of the PAI are changed. The first multicast group now comprises the mobile terminals 510a, 510b and the nomadic node 511. The second multicast group comprises the mobile terminals 510c-510e. The LF BS 530 sends a first beam 580a, thereby multicasting PAI including information relating to the reference points 540a-540c to the first multicast group, and a second beam 580b, thereby multicasting PAI including information relating to the reference points 540d, 540e to the second multicast group. A beam width of the corresponding multicast beams may be adapted according to the positions of the reference points whose PAI is encoded in the beams and the updated RoI of the requesting mobile terminals.

[0204] The grouping of the mobile terminals may be signaled to the TRPs which can decide how to beamform the PAI to the corresponding multicast group. Alternatively, the location server may assign TRPs for transmitting the PAIS.

[0205] FIGS. 6a and 6b show scenarios for determining a region of interest and signaling according to an embodiment.

[0206] In FIG. 6a, a mobile terminal 610 determines its own 2D position without using the reference signal or the positioning assistance information, for example using GNSS. Assuming that the position error distribution is a bi-variate Gaussian, the coarse position 680 is given by an error ellipse that corresponds to the covariance matrix of the 2D positioning estimate of mobile terminal 610. This error ellipse is the RoI that may be signaled to the network in order to receive a beamformed PAI in a unicast.

[0207] In FIG. 6b, the Rot is determined for a group of mobile terminals 610a-610d. First, each mobile terminal determines its own coarse position as depicted in FIG. 6a. Thereafter, mobile terminals 610a collects the coarse positions 680b, 380c, 680d of the mobile terminals 610b, 610c, 610d, respectively and generates a RoI 670 covering the coarse positions of itself (680a) and of the other three mobile terminals (680b-680d). The Rot 670 is signaled to the network in order to receive the PAI for the group either in multicast or broadcast fashion. Alternatively, the coarse positions can be sent individually by the respective mobile terminals 610a-610d and the network decides the mobile terminal grouping and the transmission method (unicast, broadcast, multicast) for the PAI for each mobile terminal.

[0208] In summary, the present disclosure relates to devices and methods for determining a position of a mobile terminal with assistance from a wireless communication system. The mobile terminal is configured to receive a reference signal from a reference point of the wireless communication system, to receive a positioning assistance information related to the reference point, and to determine a position of the mobile terminal based on the positioning assistance information and the reference signal.

[0209] While the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. From reading the present disclosure, other modifications will be apparent to a person skilled in the art. Such modifications may involve other features, which are already known in the art and may be used instead of or in addition to features already described herein.

[0210] The invention has been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The devices and their components may be embodied as hardware alone, for example as circuits and ASICs, or as a combination of hard- and software, for example a processor executing a program. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0211] Although the present invention has been described with reference to specific features and embodiments thereof, it is evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded simply as an illustration of the invention as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present invention.