EP2697736A1

EP2697736A1 - An apparatus and associated methods

Info

Publication number: EP2697736A1
Application number: EP11863701.6A
Authority: EP
Inventors: Timo Petteri Karttaavi
Original assignee: Nokia Oyj; Nokia Inc
Current assignee: Nokia Technologies Oy
Priority date: 2011-04-15
Filing date: 2011-04-15
Publication date: 2014-02-19
Also published as: WO2012140476A1; EP2697736A4

Abstract

In one or more embodiments described herein, there is provided an apparatus comprising a processor, and a memory having computer program code stored thereon. The computer program code and memory are configured to, when run on the processor, cause the apparatus to determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna, and also to discriminate the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources.

Description

An apparatus and associated methods Technical Field

The present disclosure relates to the field of radio frequency identification signalling, associated methods, computer programs and apparatus. Certain disclosed aspects/embodiments relate to portable electronic devices, in particular, so-called hand- portable electronic devices which may be hand-held in use (although they may be placed in a cradle in use). Such hand-portable electronic devices include so-called Personal Digital Assistants (PDAs).

The portable electronic devices/apparatus according to one or more disclosed aspects/embodiments may provide one or more audio/text/video communication functions (e.g. tele-communication, video-communication, and/or text transmission (Short Message Service (SMS)/ Multimedia Message Service (MMS)/emailing) functions), interactive/non-interactive viewing functions (e.g. web-browsing, navigation, TV/program viewing functions), music recording/playing functions (e.g. MP3 or other format and/or (FM/AM) radio broadcast recording/playing), downloading/sending of data functions, image capture function (e.g. using a (e.g. in-built) digital camera), and gaming functions.

Background

The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the present disclosure may or may not address one or more of the background issues.

Summary

In a first aspect, there is provided an apparatus comprising:

a processor; and

a memory having computer program code stored thereon, the computer program code and memory being configured to, when run on the processor, cause the apparatus to: determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and

discriminate the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources.

The apparatus may be caused to discriminate the radio frequency identification signalling from a particular source based on whether one or more of the multiple sources have circular polarisation characteristics indicative of reflection.

The apparatus may be caused to determine that one or more of the multiple sources have circular polarisation characteristics indicative of reflection by identifying, for respective sources, if the received radio frequency identification signalling comprises any circularly depolarised component.

The apparatus may be caused to determine whether one or more of the multiple sources have circular polarisation characteristics indicative of reflection by comparing, for respective sources, the signal strengths of:

the circularly polarised component of the received radio frequency identification signalling in the original polarisation direction; and

any circularly depolarised component of the received radio frequency identification signalling.

The apparatus may be caused to determine that a given source has experienced reflection if the ratio of the signal strengths of the circularly polarised and depolarised components of respective signalling exceeds a predetermined threshold.

The apparatus may be caused to set the predetermined threshold according to ambient factors.

The apparatus may be caused to determine that radio frequency identification signalling comprises a circularly depolarised component if the radio frequency identification signalling comprises circularly polarised components in the opposite direction to the original polarisation direction. The original polarisation direction may be right handed circular polarisation, and the opposite depolarised direction may be left handed circular polarisation. The original polarisation direction may be left handed circular polarisation, and the opposite depolarised direction may be right handed circular polarisation.

The apparatus may be caused to reject the radio frequency identification signalling from any source determined to have experienced reflection.

The apparatus may be caused to receive circularly polarised radio frequency signalling from radio frequency identification tags, the circular polarisation of the transmitted signalling being in a predetermined circular polarisation direction.

The apparatus may comprise a single directional antenna configured to receive radio identification frequency signalling.

The apparatus may comprise a first antenna configured to receive radio frequency identification signalling polarised in a first direction, and a second antenna configured to receive radio frequency identification signalling polarised in a direction opposite to that of the first direction.

The apparatus may be caused to compare the circular polarisation direction of received radio frequency signalling with a predetermined circular polarisation direction.

The apparatus may be one or more of a:

portable electronic device, portable telecommunications device, or a module for a portable electronic/telecommunications device.

In a second aspect, there is provided an apparatus configured to provide circularly polarised radio frequency identification signalling.

The apparatus of the second aspect may be configured to provide radio frequency identification signalling in a predetermined direction of circular polarisation.

In another aspect described herein, there is provided a system comprising the apparatus of the first aspect, and one or more apparatus of the second aspect. In another aspect described herein, there is provided a processor configured to:

determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and

In another aspect described herein, there is provided a method comprising:

determining respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and

discriminating the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources.

In another aspect, there is provided an apparatus, comprising:

a determinator configured to determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and

a discriminator configured to discriminate the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources.

In another aspect, there is provided an apparatus, comprising:

means for determining configured to determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and

means for discriminating configured to discriminate the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources. In another aspect described herein, there is provided a computer program comprising computer program code configured to, upon being executed, perform at least the following:

In another aspect there is provided a computer readable medium comprising the computer program of the aspect immediately above stored thereon.

The present disclosure includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. Corresponding means for performing one or more of the discussed functions are also within the present disclosure.

Corresponding computer programs for implementing one or more of the methods disclosed are also within the present disclosure and encompassed by one or more of the described embodiments.

Reference to a processor or a memory can be considered to be reference to one or more processors or memories.

The above summary is intended to be merely exemplary and non-limiting. Brief Description of the Figures

A description is now given, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 shows prior art radio frequency identification signalling detection.

Figure 2 shows difficulties with prior art radio frequency identification signalling detection. Figure 3 shows an apparatus according to an embodiment of the present disclosure. Figure 4 shows an example of the operation of an embodiment. Figures 5a and 5b explain the principle behind the operation of various embodiments. Figure 6 shows another example of the operation of an embodiment.

Figure 7 shows a method of another embodiment.

Figure 8 shows further embodiments.

Figure 9 illustrates schematically a computer readable media providing a program according to an embodiment of the present invention.

Description of Example Aspects/Embodiments

Radio frequency identification (RFID) tags are RFID sources that are used with many items for many different purposes, such as electronically readable labels in shops, or in warehouses, or the like. These tags are scanned using devices that act as RFID tag readers. Figure 1 illustrates how such a reader can be pointed at a target RFID to read a particular tag that the reader is aimed at by the user.

There can sometimes be neighbouring RFID tags that get in the way of reading the target tag. Some RFID tag readers can discriminate the target tag from adjacent interfering tags/sources because the radio frequency identification signalling received from those tags has a lower signal strength than that of the signalling received from the target tag (for example, see Figure 1 , where the adjacent tag may provide a lower signal strength). The signalling from the other tags can therefore be rejected in favour of the signalling from the target tag.

However, there are some situations in which existing tag readers are not capable of distinguishing interfering sources from a particular target source. Figure 2 illustrates an example of one of these situations. In this example, the target tag has been targeted by a user with a tag reader. There is also an interfering tag, and although this tag is not immediately adjacent to the target tag, its RFID signalling is reflected off surfaces in such a way that it is received by the reader at a similar signal strength to the signalling from the target tag.

This means that the reader is not able to reliably discriminate between the two signals and therefore cannot reject the signalling from the undesired interfering tag in favour of the signalling from the target tag because it cannot tell the difference between the two. In some other situations, the interfering tag may even have a stronger received signal strength than that of the target tag (e.g. where the reflecting surface is conductive). These difficulties are disadvantageous for users.

There are other situations in which the geometry of the area in which reading is to be performed introduces reflections from surroundings that can cause false readings.

Such embodiments discriminate the radio frequency identification signalling from a particular source based on whether one or more of the multiple sources provide signalling with circular polarisation characteristics indicative of reflection. Reflection of circularly polarised radio frequency identification signalling (in one direction) causes depolarisation of at least some of the signalling. This causes the received signalling to contain a component that is circularly polarised in the original polarisation direction (as per the original RFID signalling), and also to contain a component that is circularly polarised in the opposite direction to the original polarisation direction.

As a result, received signalling that contains any depolarised component, or a component that is polarised in the opposite direction to the original circular polarisation direction, can be considered to be indicative of reflection, and signalling from that source can be excluded for the purposes of discriminating signalling from a particular source of interest. Similarly, if RFID signalling is determined to contain no depolarised component then it is likely that this has not undergone reflection and should not necessarily be excluded when considering which source is the particular source of interest.

We will now describe a first embodiment of the present disclosure with reference to Figure 3. Figure 3 shows an apparatus 100 comprising a processor 110, memory 120, input I and output O. In this embodiment only one processor and one memory are shown but it will be appreciated that other embodiments may utilise more than one processor and/or more than one memory.

In this embodiment of Figure 3 the apparatus 100 is an application specific integrated circuit (ASIC) for a portable electronic device (such as an RFID tag reader, not shown). In other embodiments, the apparatus 100 can be a module for such a device, or may be the device itself with respective processors/memories. The processor 1 0 may be, in such a case, a general purpose CPU of a portable electronic device and the memory 120 is general purpose memory comprised by such a portable electronic device. The module for the device may comprise the aforementioned general purpose CPU and memory.

The input I allows for receipt of signalling to the apparatus 100 from further components, such as an antenna that receives radio frequency identification signalling, or components of a portable electronic device or the like. The output O allows for onward provision of signalling from within the apparatus 100 to further components. In this embodiment the input I and output O are part of a connection bus that allows for connection of the apparatus 100 to further components.

The processor 110 is a processor dedicated to executing/processing information received via the input I in accordance with instructions stored in the form of computer program code on the memory 120. The output signalling generated by such operations from the processor 110 is provided onwards to further components via the output O.

The memory 120 is a computer readable medium (solid state memory in this example, but may be other types of memory such as a hard drive) that stores computer program code. This computer program code stores instructions that are executable by the processor 110, when the program code is run on the processor 110.

In this embodiment, the input I, output O, processor 110 and memory 120 are all electrically connected to one another internally to allow for electrical communication between the respective components I, O, 110, 120. In this example, the components are all located proximate to one another so as to be formed together as an ASIC, in other words, so as to be integrated together as a single chip/circuit that can be installed into an electronic device. In other embodiments, one or more or all of the components may be located separately from one another (for example, throughout a portable electronic device). In other embodiments, the functionality offered by each of the components may be shared by other functions of a given device, or the functionality required by each of the components may be provided by components of a given device. The memory 120 can also be constituted by, or subdivided into, ROM, RAM, Flash memory, or the like.

The operation of the present embodiment will now be described, and the functionality of the computer program code will be explained.

In this embodiment, the apparatus 100 is integrated as part of a portable electronic device 200 that can provide for RFID tag reading. The device 200 has a directional antenna (not shown) that can receive radio frequency identification signalling from tags that it is directed at (in other embodiments the apparatus 100 may actually comprise the antenna). In this example, the antenna is a directional antenna that has a directional pickup pattern so it receives signalling most strongly when the antenna is pointing straight at the source so as to be substantially aligned with the source. The further to the side of the sensitive region of the antenna the source is, the less strongly the signalling from that source is received.

The device 200 is useable to detect signalling from RFID tags that transmit circularly polarised RFID signalling. In this example, the tags transmit RFID signalling that is right- handed circular polarisation signalling (RHCP) but of course the signalling may instead be left-handed (LHCP).

In Figure 4, the device 200 is pointed at a target tag Oust like in Figure 2 - we have used reference numeral 200 in brackets in Figures 1 and 2 as it will be appreciated that at least device 200 and other embodiments described herein can be useable in scenarios as depicted in these figures). Signalling from the target tag is received by the device 200. In addition to this, signalling from the interfering tag is received by the device 200 through reflection of the signal off of the wall on which the target tag is located.

Because the signalling from the interfering tag has experienced reflection, the circular polarisation of the signalling will be affected and the circular polarisation characteristics of that signalling will be changed (no longer providing just right-handed circularly polarised (RHCP) RFID signalling). In contrast, the signalling from the target tag has not experienced reflection, and therefore the circular polarisation of the target tag signalling will not have been changed (still providing only RHCP RFID signalling) and the characteristics will be the same as those which were originally transmitted.

From this, it can be seen that the respective polarisation characteristics of signalling from multiple sources can be used to discriminate signalling from a particular source, i.e. the target tag. In other words, the polarisation characteristics determined from the signalling of the interfering source (i.e. not the particular source of interest) will be indicative of reflection and will be different to the polarisation characteristics of the target tag.

Therefore, even in cases where the respective total signal strengths of the two tags are approximately the same (as in this scenario in Figure 4), it is possible to discriminate between a particular source of interest (i.e. the target tag) and sources that the user is not interested in (i.e. any other sources that have been reflected, like the other interfering tag).

The exact differences between polarisation characteristics of reflected and unreflected signalling will now be explained with reference to Figures 5a and 5b.

Figure 5a illustrates a right-handed circularly polarised wave. Polarization in electromagnetic waves is usually characterized by the orientation of the electric field perpendicular to the direction of propagation (horizontal or vertical, for simplicity). All other orientations can be construed as a sum of two such orthogonal components added in-phase. When the components are equal in magnitude and the phase shift is 90 degrees, the polarization is circular. This can be represented by a rotating phasor that can turn in either direction, hence RHCP and LHCP.

This a complex motion described by this equation:

E = E_h ^■ sin ωί · h + E_v · ms m ^■ v

There is a horizontal component and a vertical component that vary in time according to this equation, and that superimpose on one another to create circularly polarised signalling. In effect, the horizontal and vertical components are time-varying and sum together to give a rotating electromagnetic field (the RFID signalling).

Taking this a step further, if two orthogonal linear polarization components (which themselves define simple case of circular polarisation as discussed above) are added with a linearly polarised component, the result is elliptical polarization. This is illustrated in Figure 5b. The elliptical polarisation of sub-figure 'A' can therefore be broken down into components of circular polarisation 'B' and linearly polarised component 'C.

This linearly polarised component can also be broken down into a linear combination of two opposite circular polarizations (i.e. LHCP + RHCP) with appropriate magnitudes. This is because they will combine in such a way that their time-varying components cancel each other out to leave only a linearly polarised component. This is illustrated in Figure 5b, with component 'D', and components Έ' and 'F' which form the alternative expression of the linearly polarised component 'C.

Normally, directional antennas used in RFID tag readers are made so as to only be responsive to polarisation in one direction so that they can automatically reject delayed/reflected components of the same signal. This embodiment utilises a single directional antenna that is response to polarisation in more than one direction so that any signalling that is not polarised in the way that would otherwise be expected for desired signalling can be used to verify/check whether certain signalling has been received directly/indirectly, via reflection, or the like.

For completeness, it should be pointed out that the use of a single directional antenna to receive two different orientations of circularly polarised signalling would require a specialised arrangement for the antenna to be able to distinguish between the different orientations of polarisation. For example, the antenna may have two separate output feeds that separate out the two circular polarisations, or the antenna may be switched rapidly back and forth between respective modes where one mode detects polarisation in one direction and the other detects polarisation in the other direction. Another embodiment described below uses two separate antennas for each respective polarisation direction. When a propagating wave with a linear polarization hits a reflecting boundary, the linear polarization components (parallel/perpendicular to the surface normal) undergo different transformations in terms of phase and magnitude. As a result, the reflected signalling will have different complex reflection coefficients dependent on the reflection that the signalling has experienced. The exact change in the signalling will ultimately depend on the material(s) that the signalling has reflected off and the angle of incidence of the signalling off those materials.

In the case of circular polarization, this introduces a degree of ellipticity (as illustrated in Figures 5a and 5b). This effectively translates into a degree of depolarisation of the original circularly polarised signalling. This can be received by a tag reader (such as device 200) as signalling having a component that is circularly polarised in the original direction of polarisation, and a further component that is circularly polarised in the opposite direction (e.g. RHCP + LHCP).

In general, with conducting surfaces this effect is very strong. For example, if a wave were to reflect off of a perfectly conducting plane, RHCP can change to become entirely LHCP and vice versa.

In most cases, the effect a reflection has on an electromagnetic wave depends on the orientation of the polarization of the incident wave. In the case of circular polarization this results in depolarisation. In other words, some of the energy is transferred from, for example, right-handed circular polarization (RHCP) to left-handed circular polarization (LHCP) (or vice versa). This effect can be detected in the receiver by receiving the LHCP signalling with a suitable antenna. By comparing the levels of RHCP and LHCP, suspect signalling can be identified as having experienced reflection.

In summary, by using circularly polarised radio frequency identification signalling it is possible to discriminate a particular source from multiple sources based on respective circular polarisation characteristics of the signalling from the multiple sources, as these can serve as indicators as to which signalling sources have experienced reflection.

We will now describe a more detailed example with reference to Figure 6. In Figure 6, a different device 300 with apparatus 100 is used to read a target tag. The device 300 is substantially the same as device 200 except that it additionally comprises two directional antennas 330, 340. The first antenna 330 is arranged to receive RHCP signalling, and the second antenna 340 is arranged to receive LHCP signalling. This effectively splits the duty of receiving signalling in the original polarisation direction and receiving signalling in the opposite direction to the original polarisation direction between different antennas. This is also different to existing designs, because in existing RFID tag readers often only one antenna is used as there is no interest in any reflected signalling (as has been discussed above).

In this example, the target tag and interfering tag are arranged to transmit circularly polarised radio frequency identification signalling that is circularly polarised in a predetermined direction. This predetermined direction is common to both tags. In this example, both are transmitting RHCP signalling, but in other embodiments the signalling may be LHCP. It will be appreciated that the apparatus 100 and devices 200/300 rely on knowing that all sources are transmitting signalling with circular polarisation in a particular direction, for example, all tags transmitting with RHCP, or all tags transmitting with LHCP.

As can be seen, unreflected signalling from the target tag contains no LHCP component while reflected signalling from the interfering RFID tag contains RHCP and LHCP components. This device 300 needs to be able to identify the particular source that the user is interested in from this information alone, but in other embodiments more information could be provided (for example, user provided information or confirmation, or payload data within respective signalling).

The antennas 330, 340 pick up the respective components of signalling from the target and interfering tags. From the received signalling, the device 300 can then identify that there are two sources, and that one of these sources is a source that has provided signalling that has a component of LHCP (a circular polarisation characteristic that is indicative of reflection), and that the other source is a source that has provided signalling without any component of LHCP (a circular polarisation characteristic that is indicative of no reflection). Therefore, the device 300 discriminates that the particular source of interest to the user (i.e. the target tag) is the source with no LHCP component as the circular polarisation characteristic of the target tag's signalling indicates it was directly received, and the circular polarisation characteristic of the interfering tag's signalling indicates it was received via reflection.

It should be noted that in some scenarios there may be an element of ambient reflection occurring and as a result there will be some background level of LHCP associated with any signalling received from a source. In practice, atmospheric effects and non-idealities in antennas can cause some depolarisation which has to be taken into account.

To combat this, the apparatus 100 (or device 200/300 having the apparatus) can be configured to compare the respective signal strengths for the RHCP and LHCP to ascertain whether the ratio of the two exceed a predetermined threshold. This can be considered to be a predetermined ambient threshold that prescribes an acceptable level of reflected signalling due to ambient factors if ambient factors are taken into account in setting the threshold. If the ratio exceeds this threshold, then it can be determined that the signalling has experienced reflection in such a way that it should be excluded as desired signalling.

If the ratio does not exceed the (ambient) threshold, then it can be determined that the signalling has not experienced reflection in such a way that it should be excluded as desired signalling. That way, signalling from a particular source of interest should not be excluded even if there is some background (or ambient) level of reflected signalling associated with that particular source of interest. This ratio can be considered to reflect a 'reliability factor', in effect how reliable a particular source's signalling is as a potential particular source of interest.

The antennas of device 300 can:

a) have separate receivers;

b) use a common receiver via a switch; and/or

c) be incorporated into a single antenna array with different feeds and/or phasing schemes for the two cases.

In another variation of the device 300, the following steps are undertaken when the user points the device 300 at the target tag and initiates the reading sequence: 1. Information from all the tags within range are read and the corresponding signal strength (RSS) values are measured with the first antenna 330 to measure the RHCP.

2. In addition, the signal strengths for the tags are measured also with the second antenna 340 to measure the LHCP. In another example, a single antenna can do both steps 1 and 2.

3. A reliability factor is then calculated for each received tag which is based on the ratio of the respective signal strengths of RHCP and LHCP. This ratio can be considered to be an indicator of reliability of the signal.

4. Normally, the highest signal strength value should correspond to the tag that the user was pointing at. However if the reliability factor is too low, it suggests that the signal was reflected and corrective measures should be taken. This can include one or more of:

Repeating the read sequence;

Warning the user about the conflict; and

Choosing another tag according to preset rules.

5. Once a tag has been selected that is sufficiently reliable, the corresponding application process in the reader device is started based on the received tag information.

Figure 7 also shows more detailed steps involved in another variation of this device 300. In this example, the device receives the signalling and measures the respective RHCP and LHCP signal strengths (step 701). The device then compares the two RHCP/LHCP signal strengths for a given source's signalling together to establish a ratio (step 702).

This ratio is compared to a predetermined threshold (step 703). If the predetermined threshold is exceeded by that ratio then the signalling for that source is rejected (step 704) because it fails the reliability standard prescribed by that predetermined threshold. If, however, the predetermined threshold is not exceeded by the ratio of RHCP/LHCP signal strengths for a given source's signalling then the signalling for that source is kept (step 705) because it meets the reliability standard prescribed by the predetermined threshold.

The previous steps are repeated (either sequentially or simultaneously) for all source's signalling (step 706). Once this process is complete then the results are provided to the user. This could involve just presenting a single source that has been discriminated as being most reliable (e.g. strongest RHCP to LHCP ratio) or could involve ranking a certain number (or even all) of the remaining tags that have not been rejected by this method according to their ratio (step 707). The user can then select the particular source/tag they are interested based on this presented/ranked information.

It should be noted that although the tags transmit circularly polarised signalling and the apparatus 100 uses this to identify/determine reflection of signals, the payload data carried by the respective signalling could be encoded using linear polarisation. As circularly polarised signalling is just the summing of two time-varying linear components this just means that the other linear component contains no information and is merely added to transmitted signalling to aid in source discrimination.

It will be appreciated that in one embodiment there is provided a system that utilises at least one device like device 200/300 for reading RFID tags, and that the RFID tags in the system are configured to transmit circularly polarised signalling in a predetermined direction (e.g. RHCP). This is to ensure the device 200/300 knows that any signalling received with LHCP is indicative of a degree of reflection. If different tags use different directions of circular polarisation (e.g. some RHCP, some LHCP) it would be difficult to ascertain which respective signalling have experienced reflection and which are just polarised in the opposite direction to one another.

Decision rules for various situations can be designed taking into account the system properties. These depend on several factors in the system implementation such as antenna qualities, propagation environment, the application itself (consequences of false readings) etc. A skilled person would appreciate how to incorporate such rules into a device 200/300 or apparatus 100. These rules can be stored on the memory 10.

One advantage of the above embodiments is that reflected signalling that could otherwise confuse the remote RFID system can be identified as non-desired signalling (i.e. not emanating from a particular source of interest) and thereby rejected. This helps to improve reliability of RFID detection and reading. It will be appreciated that one or more of the above embodiments can be integrated into existing tag readers and antennas. Figure 8 illustrates schematically a device 400 comprising the apparatus 100 described herein. The input I of the apparatus 100 is connected to a directional antenna 405 and the output O is connected to a sub-circuit 470 receives output signalling from the apparatus 100. The apparatus 100 operates in accordance with the apparatus 100 described above.

The device 400 may be an electronic device, a portable electronic device, a portable telecommunications device, or a module for any of the aforementioned devices. The apparatus 100 can be provided as a module for such a device 400, or even as a processor for the device 400 or a processor for a module for such a device 400. The device 400 also comprises a processor 460 and a storage medium 480, which may be electrically connected to one another by a data bus 450.

The processor 460 is configured for general operation and control of the apparatus 100 by providing signalling to, and receiving signalling from, the other device components to manage their operation.

The storage medium 480 is configured to store computer code configured to perform, control or enable the making and/or operation of the apparatus 100. The storage medium 480 may also be configured to store settings for the other device components. The processor 460 may access the storage medium 480 to retrieve the component settings in order to manage the operation of the other device components. The storage medium 480 may be a temporary storage medium such as a volatile random access memory. On the other hand, the storage medium 480 may be a permanent storage medium such as a hard disk drive, a flash memory, or a non-volatile random access memory.

Figure 9 illustrates schematically a computer/processor readable media 500 providing a program according to an embodiment of the present invention. In this example, the computer/processor readable media is a disc such as a digital versatile disc (DVD) or a compact disc (CD). In other embodiments, the computer readable media may be any media that has been programmed in such a way as to carry out an inventive function.

It will be appreciated to the skilled reader that any mentioned apparatus/device and/or other features of particular mentioned apparatus/device may be provided by apparatus arranged such that they become configured to carry out the desired operations only when enabled, e.g. switched on, or the like. In such cases, they may not necessarily have the appropriate software loaded into the active memory in the non-enabled (e.g. switched off state) and only load the appropriate software in the enabled (e.g. on state). The apparatus may comprise hardware circuitry and/or firmware. The apparatus may comprise software loaded onto memory. Such software/computer programs may be recorded on the same memory/processor/functional units and/or on one or more memories/processors/functional units.

In some embodiments, a particular mentioned apparatus/device may be preprogrammed with the appropriate software to carry out desired operations, and wherein the appropriate software can be enabled for use by a user downloading a "key", for example, to unlock/enable the software and its associated functionality. Advantages associated with such embodiments can include a reduced requirement to download data when further functionality is required for a device, and this can be useful in examples where a device is perceived to have sufficient capacity to store such pre-programmed software for functionality that may not be enabled by a user.

It will be appreciated that the any mentioned apparatus/circuitry/processor may have other functions in addition to the mentioned functions, and that these functions may be performed by the same apparatus/circuitry/processor. One or more disclosed aspects may encompass the electronic distribution of associated computer programs and computer programs (which may be source/transport encoded) recorded on an appropriate carrier (e.g. memory, signal).

It will be appreciated that any "computer" described herein can comprise a collection of one or more individual processors/processing elements that may or may not be located on the same circuit board, or the same region/position of a circuit board or even the same device. In some embodiments one or more of any mentioned processors may be distributed over a plurality of devices. The same or different processor/processing elements may perform one or more functions described herein.

It will be appreciated that the term "signalling" may refer to one or more signals transmitted as a series of transmitted and/or received signals. The series of signals may comprise one, two, three, four or even more individual signal components or distinct signals to make up said signalling. Some or all of these individual signals may be transmitted/received simultaneously, in sequence, and/or such that they temporally overlap one another.

With reference to any discussion of any mentioned computer and/or processor and memory (e.g. including ROM, CD-ROM etc), these may comprise a computer processor, Application Specific Integrated Circuit (ASIC), field-programmable gate array (FPGA), and/or other hardware components that have been programmed in such a way to carry out the inventive function.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole, in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that the disclosed aspects/embodiments may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the disclosure.

While there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods described may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. Furthermore, in the claims means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.

Claims

1. An apparatus, comprising:

a processor;

a memory having computer program code stored thereon, the computer program code and memory being configured to, when run on the processor, cause the apparatus to:

2. The apparatus of claim 1 , wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

discriminate the radio frequency identification signalling from a particular source based on whether one or more of the multiple sources have circular polarisation characteristics indicative of reflection.

3. The apparatus of claim 1 , wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

determine that one or more of the multiple sources have circular polarisation characteristics indicative of reflection by identifying, for respective sources, if the received radio frequency identification signalling comprises any circularly depolarised component.

4. The apparatus of claim 1 , wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

determine whether one or more of the multiple sources have circular polarisation characteristics indicative of reflection by comparing, for respective sources, the signal strengths of:

5. The apparatus of claim 4, wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

determine that a given source has experienced reflection if the ratio of the signal strengths of the circularly polarised and depolarised components of respective signalling exceeds a predetermined threshold.

6. The apparatus of claim 5, wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to set the predetermined threshold according to ambient factors.

7. The apparatus of either claims 3 or 4, wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

determine that radio frequency identification signalling comprises a circularly depolarised component if the radio frequency identification signalling comprises circularly polarised components in the opposite direction to the original polarisation direction.

8. The apparatus of claim 3, wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

reject the radio frequency identification signalling from any source determined to have experienced reflection.

9. The apparatus of claim 1 , wherein the computer program code and memory are configured to, when run on the processor, cause the apparatus to:

compare the circular polarisation direction of received radio frequency signalling with a predetermined circular polarisation direction.

10. The apparatus of claim 1, wherein the apparatus is one or more of a:

11. An apparatus, configured to provide circularly polarised radio frequency identification signalling.

12. The apparatus of claim 11, wherein the apparatus configured to provide radio frequency identification signalling in a predetermined direction of circular polarisation.

13. A system comprising the apparatus of claim 1, and one or more apparatus of claim 11.

14. A processor configured to:

15. A method comprising:

16. A computer program comprising computer program code configured to, upon being executed, perform at least the following:

determine respective circular polarisation characteristics of radio frequency identification signalling received from multiple sources by a directional antenna; and discriminate the radio frequency identification signalling from a particular source based on the respective circular polarisation characteristics of the radio frequency identification signalling received from the multiple sources.

17. A computer readable medium comprising the computer program of claim 16 stored thereon.