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England and Wales Court of Appeal (Civil Division) Decisions
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Cite as:  EWCA Civ 1619
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Case No: A3/2020/2075
IN THE COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM THE BUSINESS AND PROPERTY COURTS OF ENGLAND AND WALES, INTELLECTUAL PROPERTY LIST (ChD), PATENTS COURT
Mr Justice Birss
Royal Courts of Justice
Strand, London, WC2A 2LL
Date: 10 November 2021
LORD JUSTICE NEWEY
LORD JUSTICE ARNOLD
LORD JUSTICE WARBY
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(1) OPTIS CELLULAR TECHNLOGY LLC
(2) OPTIS WIRELESS TECHNOLOGY LIMITED
(3) UNWIRED PLANET INTERNATIONAL LIMITED
- and -
(1) APPLE RETAIL UK LIMITED
(2) APPLE DISTRIBUTION INTERNATIONAL LIMITED
(3) APPLE INC
- - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - -
Guy Burkill QC and Brian Nicholson QC (instructed by Wilmer Cutler Pickering Hale and Dorr LLP) for the Appellants
Mark Chacksfield QC, Thomas Jones and Henry Edwards (instructed by EIP Europe LLP and Osborne Clarke LLP) for the Respondents
Hearing dates : 20-21 October 2021
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Covid-19 Protocol: This judgment was handed down remotely by circulation to the parties' representatives by email, release to BAILII and publication on the Courts and Tribunals Judiciary website. The date and time for hand-down is deemed to be at 10:30am on 10 November 2021
Lord Justice Arnold:
The skilled person
Common general knowledge
7. GSM is an FDMA [Frequency Division Multiple Access]/TDMA [Time Division Multiple Access] system. When a phone call is in progress the phone transmits digital signals to the base station at a particular frequency which has been allocated to it and in one of eight time slots at that frequency. Each time slot is 577 microseconds long. The uplink signals from each phone in a cell are on a different combination of frequency and time slot. From the point of view of the receiver, all the radio signal energy at that frequency at a particular time is signal from just one phone. Everything else in that time and frequency is noise. The downlink from the base station to the phones works the same way.
10. Unlike GSM, UMTS uses radio access technology called wideband CDMA (Code Division Multiple Access). All the phones in a cell transmit in the same broad frequency band at the same time. What distinguishes one signal from another is a scrambling code. Each transmitter has a different code. The codes are orthogonal which means that (in theory) they can all be uniquely distinguished from one another. From the point of view of the receiver, the radio signal energy in a frequency band at all times is made up of all the transmitters ‘talking’ at once. If the receiver wants to ‘listen’ to a particular transmitter it uses the right code to pull out from that overall radio energy the signal sent by that transmitter. Everything else, including all the other transmitters, is effectively noise. The base stations in UMTS (called Node Bs) also broadcast something called the CPICH. This is a ‘pilot’ channel which allows phones to find the signals from that base station using the primary scrambling code for the cell.
12. In a cellular telecommunications network handover is crucial in order to maintain connections (phone calls or data). The quality of the channel between the phone and the base station in one cell may start to deteriorate but there may be another cell available which can provide a better connection. The phone is handed over from one base station to another. This can happen seamlessly in the middle of the phone call or data connection so that the user does not notice. It may need to happen very quickly. There are different kinds of handover. One sort is known as network controlled mobile assisted handover. The decision to handover is made by the network not the phone, but the phones assist the process by using their radio receivers to make measurements of neighbouring cells and then reporting these results to the network so that the network can make a decision. Another sort of handover can be controlled by the phone itself.
13. When the GSM system began, the only handovers contemplated within its standard were GSM to GSM, in other words intra-RAT handovers. These included handovers between different frequency bands within GSM. Nevertheless given the variety of RATs which were in existence in the 1990s, the general idea of inter-RAT handover was well known. Focussing in particular on GSM and UMTS, by the priority date it was clear that so called dual mode phones would be available which were capable of working in GSM or UMTS and there would be a need for inter-RAT handovers in which a phone could be handed over from a GSM cell to a UMTS cell and vice versa.
31. RATs have a land side, which refers to the fixed part of the network, as distinct from the air side, i.e. the phone. The phone is mobile. The land side communicates with the phone over the air interface. The land side of GSM consisted of essentially three kinds of boxes: the MSC [Mobile Switching Centre], the BSC [Base Station Controller] and the BTS [Base Transceiver Station]. The BTS is the base station. It is often depicted as an aerial. Each cell has a BTS. The BSCs control a number of BTSs and an MSC in turn sits above a number of BSCs forming a hierarchy. ….
32. When measurements are made in GSM for handover purposes the phone can measure the received signal level of a cell such as a neighbour. This is called RXLEV. RXLEV is a measure of power and its units are dBm [decibel-milliwatts]. The quality of the received signal can be represented by a value called RXQUAL. RXQUAL is a kind of signal to noise ratio. As a ratio its units are dB [decibels]. Generally a phone can measure RXLEV for both the serving cell to which it is connected and neighbour cells while it only measures or reports RXQUAL for the serving cell.
33. In GSM there are two available control channels on the uplink, SACCH and FACCH. These letters stand for Slow Associated Control Channel and Fast Associated Control Channel. The SACCH worked as follows. Together the eight time slots of 577 µsec each form one single frame of about 4.6 msec. A multiframe amounts to 26 frames and takes up about 120 msecs. In the normal case 24 of those 26 frames in a multiframe are used to carry traffic channels. The 26th frame is empty for various reasons. The 13th frame is used to send control data. One SACCH message requires four bursts, in other words four of these 13th frames. So to send one SACCH message takes about half a second (4 x 120 msecs = 480 msecs).
34. The FACCH works in a different way. Traffic channel frames are used to send FACCH messages. That means those traffic frames cannot be used to send data such as voice data. The traffic frames are said to be ‘stolen’. A FACCH message needs four frames worth of data sent over five successive frames. So it is much faster than the SACCH. Moreover, owing to the error correction methods which are used it is possible to steal a small number of traffic data bits without sacrificing connection quality at all. However for various reasons the error correction may not be able to compensate for a FACCH message, in which case using the FACCH frequently may degrade connection quality.
36. In GSM the SACCH is used to send regular measurement reports from the phone to the BSS. The normal measurement report provides the RXLEV and RXQUAL for the serving cell and the RXLEV of the 6 neighbouring cells. The 6 cells to report are the ones with the highest RXLEV. This normal measurement report takes up one whole SACCH message. Therefore if nothing else was sent on the SACCH, the phone could send two normal measurement reports per second. However the standard permits some other messages to be sent on the SACCH too. An example of another message is an SMS text message. In GSM SMS messages are sent on the SACCH. …
37. The rule is that a normal measurement report may be sent in every SACCH message and must be sent in every other SACCH message. So if, for example there was no other message to be sent, then every SACCH message would be a normal measurement report. The SACCH is never empty. The reason for this is because the regular measurement reports are used by the network to build up a picture of how conditions around the phone are changing over time. This helps make handover decisions. Nevertheless if another message such as an SMS message needed to be sent, then that other message could only use up to half the capacity of the SACCH. The SACCH would still send normal measurement reports every half a second, but every other SACCH message could be used to send the SMS (which might only need one SACCH message or might require more). This way some capacity on the SACCH was available. But that availability was at the expense of sending some measurement reports.
39. … At the relevant time two separate frequency bands, GSM 900 and DCS 1800, were established in GSM. Dual mode handsets capable of operating on either band became available, and handover between the different bands had to be catered for. The GSM standard at the time had special provisions relating to multiband handsets. The network could require multiband reporting to take place using a parameter called MULTIBAND_REPORTING. One setting meant that the phone would report the six strongest neighbouring cells irrespective of the band they were in. Picking these cells would require the phone to compare the RXLEV measurements from the various GSM cells in the two bands.
41. The Node B is the radio transceiver. The RNCs control a number of Node Bs and an MSC in turn sits above a number of RNCs forming a hierarchy. The UMTS network is sometimes called UTRAN. UMTS works in two ways, FDD [Frequency Division Duplex] and TDD [Time Division Duplex]. …
42. In UMTS measurements can be made of the strength and quality of a received signal. The value RSCP is a measure of signal strength for the cell. The letters stand for Received Signal Code Power. The reason this measure is concerned with code power is because UMTS is a CDMA system and what distinguishes each cell from its neighbour is the code (i.e. the scrambling code). Strictly the value is CPICH RSCP, i.e. RSCP after despreading on the pilot channel. The units of RSCP are dBm.
43. In UMTS signal quality can be expressed as the ratio Ec/Io (strictly Ec/I0). This is the ratio of code energy to interference. Another measure is the ratio between code energy and noise power spectral density, written as Ec/No. These two are not the same but for the purposes of this case they can be treated interchangeably. Both quantities represent a measure of signal to noise ratio and hence quality. Strictly Ec refers to energy per chip. A chip can be thought of as a single bit of a given scrambling code. The units in which Ec/Io and Ec/No are expressed are dB.
44. As of the priority date, candidates for signal characteristics to be measured and reported by the mobile for inter-frequency handover in UMTS were identified in [a] list [which] identified five candidate characteristics including RSCP and Ec/Io. The list made clear that while one of them would be mandatory, it had not been decided which one. … Moreover the range over which the individual measurement had to be expressed was undecided and so also was the mapping and format in which that information would be conveyed in UMTS.
45. Part of the task of a skilled person would be to design messages to be sent over the air interface. Techniques to do this were part of the common general knowledge. One aspect is the mapping and formatting of information.
46. In GSM … RXLEV … is encoded or ‘mapped’ into a 6 bit format in the standard GSM measurement report. A 6 bit binary number provides 64 integer values expressed in decimal numbers as 0-63. The scheme works as follows. The received power level for a cell can be expressed as a value in watts. A value in watts can also be expressed in dBm. dBm is a logarithmic scale which allows a range of powers which differ by several orders of magnitude to be expressed in a convenient way. For example -90 dBm is 10-12 watts or 1 picowatt and -30 dBm is 10-6 watts or 1 microwatt, a power level six orders of magnitude greater. In GSM the default encoding scheme is that values less than -110 dBm are all mapped to zero in the 6 bit format. Values within the range -110 to -48 dBm are mapped to the integers 1 to 62 in 1dBm increments. Values greater than -48 dBm are all mapped to the integer 63. It will be seen that there are 62 steps of 1 dBm each between -110 and -48. So if the phone measures a received power level for a GSM cell of 56 picowatts (which is 5.6 x 10-11 watts), expressed in dBm that is -72.5 dBm. That value would be encoded in the 6 bit format as 100110 (or 38). The GSM scheme has further aspects (such as a SCALE parameter) but that is not relevant. Note that this encoding is not arbitrary because, within the range a higher encoded value will represent a higher power and the steps are the same size in dBm (although not the same size in watts). That is commonly done and for good reason but it is not a necessary part of encoding. An encoding scheme could be entirely arbitrary provided both the sender and the receiver know what the rules are. The term RXLEV sometimes means the measured value and sometimes means the encoded integer. Usually there is no problem with this and the skilled person understands, but nevertheless they are two distinct entities. …
47. There is no reason why the encoding of one value in one communications protocol (say RXLEV in GSM measurement reports) has to correspond to the encoding of a different value in a different protocol (say RSCP in UMTS measurement reports). At this stage the point is simply that encoding formats can differ. …
“In accordance with a preferred embodiment of the present invention, a method for conveying measurement information from a mobile terminal in a first communication system to a second communication system is provided, whereby the measurement information related to the first communication system is conveyed to the second communication system on a control channel which can function in a non-stealing mode. For example, in accordance with the preferred embodiment, UMTS measurement information can be conveyed from an MS to a GSM BSC, in a GSM message on a Slow Associated Control Channel (SACCH).”
As can be seen, this statement is directed to the preferred embodiment of the invention.
“A mobile terminal (MS 22) operating in a GSM cell … is capable of making UMTS measurements related to the UMTS cell … and conveying them (in measurement reports) to the GSM BSC in the measurement reports on the SACCH for handover decisions. Notably, the UMTS measurement information being reported is different from the typical GSM measurement information being reported.”
“For example, a typical GSM MS continuously measures and reports (on the UL) signal strength (dBm) and quality (Bit Error Rate or BER) of its own cell, and signal strength of the Broadcast Control Channel (BCCH) carriers of the neighboring cells. On the other hand, instead of measuring signal strength in a UMTS cell, a UMTS MS measures and reports (on the UL) the Code Energy-to-Interference Ratio (Ec/I0) or Received Signal Code Power (RSCP in dBm) of the UMTS cell. Consequently, in order for an MS (e.g. 22) to convey UMTS measurement information to a GSM BSC (e.g., for handover purposes), the UMTS measurement information is preferably converted to an appropriate GSM measurement format.”
“As such, in accordance with the preferred embodiment of the present invention, an exemplary method that can be used by an MS for converting UMTS measurement information to a GSM measurement information format is described below with respect to FIGURE 2.”
This statement focusses on the use of the method described below for converting UMTS measurement information to a GSM format.
“... at step 102a of the method, the MS 22 retrieves from local memory, Ec/I0 or RSCP information … measured and stored for reporting to a GSM BSC (14). At step 102b, the MS 22 (e.g., a dual-mode MS) can also retrieve from local memory, signal strength information (dBm) measured and stored for reporting to a GSM BSC.”
Although it is not explicitly stated in this passage, it is clear from the preceding discussion that the “Ec/I0 or RSCP information” is UMTS measurement information while the “signal strength information” is GSM measurement information. This is confirmed by the text in boxes 102a and 102b (although the text in box 102a only refers to Ec/I0, and not to RSCP, no doubt for brevity).
“At step 104, the MS 22 converts the retrieved UMTS Ec/I0 or RSCP measurement information to appropriate GSM signal strength information, which can be used by the GSM BSC 14 for making handover decisions. For example, the UMTS RSCP measurement information retrieved by the MS 22 can be converted to appropriate GSM signal strength measurement information (RXLEV) by using the following equation:
RXLEV = RSCP + OFFSET(RSCP), (1)
where RXLEV represents GSM signal strength measurements [e.g., -110,-47] in dBm, RSCP represents UMTS signal strength measurements in dBm, and OFFSET represents offset values that can be constant or variable with RSCP.”
“At step 106, the MS 22 compares the converted UMTS signal strength values (derived from step 104) with the set of stored GSM signal strength values (derived from step 102b). The MS 22 then retrieves a predetermined number (e.g., 6, or the maximum number of neighboring cells included in a GSM measurement report) of the ‘best’ measurement values from step 106 to be reported in a measurement report to the GSM BSC 14.”
“The skilled reader would understand the writer to be [putting ‘best’ in inverted commas] to indicate that best is being used in a figurative sense alluding to their suitability for handover, while not pretending that necessarily one is really better than another because real handover decisions are more complicated than that and take in other factors such as loading.”
“At step 108, for this exemplary embodiment, the MS 22 sends a GSM-type measurement report for receipt at the BSC 14 (via BTS 16) on the GSM SACCH over the radio air interface 23. The GSM-type measurement report can include signal strength information about UMTS neighboring cells.”
“Alternatively, at step 106, instead of comparing the converted UMTS measurement values with GSM measurement values, the MS can convert each stored UMTS measurement value to an appropriate GSM signal strength value, and select each converted UMTS measurement value that exceeds a predetermined signal strength threshold value, for reporting to the GSM BSC 14.”
“Using the above-described method (100) in accordance with the preferred embodiment of the present invention, the UMTS measurement information from the MS 22 can be converted to a GSM measurement format and sent to the GSM BSC 14 on the SACCH for use in making handover decisions. Consequently, since the SACCH does not operate in a stealing mode, the quality of the speech and on-line data being conveyed between the MS 22 and the GSM network 10 will not be diminished due to the use of speech frames for measurement signalling.”
“The skilled person would understand that this result in paragraph  happens for two reasons. First, by converting the UMTS measurements into a GSM measurement format, the reporting can be carried out using the existing GSM measurement report. UMTS and GSM measurements have the same format and so they can replace one another in the existing report. The best cells from a pool of GSM and UMTS cells can be sent in the report. That report message is sent on the SACCH and so the reporting of UMTS measurements can take place on the SACCH and as a result does not steal from speech. Second, by converting the UMTS measurements into what is described as ‘appropriate GSM signal strength information’ (para  ln49) and ‘some adequate GSM signal strength’ (box 102a of Fig 2) the UMTS values can be compared against GSM values. This comparison can be carried out in the BSC when making handover decisions (para  ln49) and can be done in the phone in order to work out which UMTS cells to include in the standard GSM measurement report instead of GSM cells.”
“78. First, one must read the document as a whole. Overall in the specification conversion is described as one exercise albeit it has two aspects - comparability and format. The reader would not think the conversion in the context of the second alternative was different from the conversion in the first alternative. Also, looking at the document overall, the second alternative is presented as an alternative at step 106 in conversion method 100. It is not stated to be an alternative to paragraph . As written paragraph  applies to both alternatives. The same goes for earlier paragraphs  and . The language referring to preferred embodiments does not justify excluding either alternative from these other parts of the disclosure.
79. Second, it is true that the second alternative refers to selecting ‘each’ converted UMTS value which exceeds the threshold for reporting, but that would not be understood by the skilled person as a statement that an unlimited number of UMTS values should be sent. The skilled person would know that there ought to be a limit on the number sent and would see that these words were not being used to mean that the idea of using the standard GSM message was being abandoned. Far from it. The skilled person was familiar with message design and would understand, based on their common general knowledge, that there were various ways of carrying this out. That could include e.g. providing that up to six UMTS measurements would be reported with the remainder being used by GSM measurements, or providing some form of partitioning of the available space (e.g. 3 for UMTS and 3 for GSM) or some other approach again.
80. Third, it is also true that the sentence at the end of paragraph  in which the second alternative is contained does not mention a standard GSM report but the skilled person would not think that that meant a completely different approach was being proposed. The reader would not think that using the standard GSM report was mandatory, but nor would they think the second alternative excluded any such thing.”
“82. It follows from this conclusion that it is fair to say that what the patent discloses is the idea that when the phone does the comparison it may be done using real GSM measurements (first embodiment) or a GSM threshold (second embodiment). Although not stated in the patent expressly for the second embodiment, the reader would understand that both embodiments could result in a measurement report containing both UMTS and GSM cells. If (say) only three converted UMTS measurements passed the threshold test and were to be reported in a standard GSM message report with room for six cells, the phone could report the three best GSM cells in the available spaces.
83. [Counsel for Optis], as he did in the previous case, described this as the invention enabling the phone to ‘flexibly and intelligently’ allocate the limited signalling capacity available on the SACCH such that it was likely that the most useful cells are reported. This is correct to the extent that starting with a standard GSM measurement report which can include six cells, this does not enable more cells to be reported but it does allow the phone to select from the pool of both GSM and UMTS cells, choose the six ‘best’, and flexibly allocate space to those six. It is flexible in the sense that next time a report is sent, a different mix of UMTS and GSM cells may be sent. Whether it is right to call it intelligent does not matter.”
“[a] A method for conveying measurement information from a terminal in a first communication system to a second communication system, characterised by the steps of:
[b] converting a plurality of downlink measurement values associated with said first communication system to a plurality of downlink measurement values for said second communication system;
[c] comparing said converted plurality of downlink measurement values with at least one threshold measurement value; and
[d] if at least one of said converted plurality of downlink measurement values exceeds a predetermined threshold measurement value, sending said at least one of said converted plurality of downlink measurement values on a control channel to a control node in said second communication system.”
Construction of claim 1
“93. In my judgment the skilled reader would understand the patent as a whole to refer to conversion as a process with both aspects. Its purpose is to render the UMTS measurement in a form both (i) comparable with a GSM measurement and (ii) expressed in a GSM measurement format. The former makes it useful for handover decisions and the latter helps send it on the SACCH in a non-stealing mode. The reader of the patent would not think the conversion referred to had taken place if only one of these two things was achieved.
94. The reader would understand the term conversion as it is used in the claim to have the same meaning as in the rest of the specification. This is not to read a gloss from the specification into the claim, it is to interpret the claim in its proper context.”
“103. To make UMTS measurements comparable with GSM measurements as required by the patent as part of conversion, what is required is that the UMTS value be expressed as if it was a GSM measured value, even though it is not, and thereby allow ranking of the cells from both GSM and UMTS on a common scale.
104. As the exemplary equation in the specification shows, one way of doing this could be to add an offset to the UMTS value to make it comparable. However that is not the only way. As the skilled person would understand, information from different sources can also be made comparable by a process of encoding and mapping to an appropriate scale. The temperature example relied on by [counsel for Optis] illustrates the point.”
“Where a patentee has used general language in a claim, but has described the invention by reference to a specific embodiment, it is not normally legitimate to write limitations into the claim corresponding to details of the specific embodiment, if the patentee has chosen not to do so. The specific embodiments are merely examples of what is claimed as the invention, and are often expressly, although superfluously, stated not to be ‘limiting’. There is no general principle which requires the court to assume that the patentee intended to claim the most sophisticated embodiment of the invention. The skilled person understands that, in the claim, the patentee is stating the limits of the monopoly which it claims, not seeking to describe every detail of the manifold ways in which the invention may be put into effect.”
“The document describes a UMTS measurement report which would be triggered to be sent if a UMTS measurement exceeds a threshold. The proposal in the document would be understood to be that it is sent on the FACCH - but that is no distinction over claim 1. Moreover the report is not a standard GSM measurement report - it is a special UMTS measurement report - but that is no distinction over claim 1 either.”
“… there is no reason based on the specification for the reader to attribute any particular significance to the use of the term ‘value’ as a way of drawing a distinction between the measurement information and the format in which it is expressed. The term is apt to refer to both. This is similar to the way RXLEV can mean the measurement or the formatted number. They are both values for RXLEV, as the skilled person understands.”
“The principle is not that a claim which contains an arbitrary feature is invalid. Merely having an arbitrary feature in a claim is not a ground of invalidity. The point of Agrevo obviousness is that if a claim is found to contain an arbitrary limitation in it, then that limitation cannot assist the patentee in defending an obviousness case. The claim still does have to be obvious over something in the state of the art - perhaps common general knowledge or some cited prior art.”
“… if conversion was an arbitrary feature [of claim 1] then I agree with Apple that the claim would be Agrevo obvious. That would be because, stripped of the conversion feature, claim 1 would cover a process in the context of inter-RAT handover from GSM to UMTS in which the phone measures a UMTS value like RSCP, compares it against a threshold and sends that UMTS measurement to the GSM network on a control channel if measurement exceeds the threshold. Whether the report itself was triggered by exceeding the threshold or whether passing the threshold led to the measurement being included in a report which was to be sent anyway does not matter. The claim covers both. The claim also covers a report on any control channel and does not require the use of any particular report. That process, couched at that level of generality, would be obvious to the skilled person at the priority date.”
“… this Agrevo obviousness objection fails because conversion is not arbitrary. At the risk of repetition, conversion has the result that the converted values have the two beneficial properties referred to above. … These beneficial properties are shared by everything within the claim. In a case in which the beneficial properties exist across the full width of the claim, there is no reason based on Agrevo or anything else why the inventors should have limited their claim to particular instances of the taking advantage of those benefits.”
“The conversion means that measurements from the first communications system are made comparable with those in the second system, and it means that measurements from the first communications system can be conveyed in the second system in the same format as measurements in that second system. These two aspects of conversion mean that the converted values have beneficial properties and so the method itself has benefits. There are two benefits. The first arises because the conversion means that the values are directly comparable between the two systems. This makes them useful for making handover decisions. It also allows a comparison to be made, between the two systems, to decide which measurements to report. The second benefit means that the values can be treated alike where format matters, such as by filling up space in a measurement report. This shows why conversion is a crucial aspect of the inventive concept.”
“As Losh says, and the skilled person would think as a matter of common general knowledge anyway, one could have the handover decision made by the phone or by the network. A critical problem with Apple’s obviousness case here is that the idea of comparing values in Losh is disclosed only as something for the purpose of making handover decisions. To the skilled person it would be obvious to do that in the phone if the phone was making handover decisions, but in that case there would be no reason to send any UMTS measurement values in a report to the GSM network. That line of thinking does not take the skilled person to a system within claim 1. On the other hand if the skilled person was not considering handover decisions in the phone, they would be considering network directed, mobile assisted, handover. Indeed that is the more attractive option for the skilled person. In that case it would be obvious (from common general knowledge anyway but also based on Losh) to send UMTS measurement information to the network. However the reference to comparison in Losh would not be understood to have any relevance to that. There is no reason to make any conversion in the phone - for the purpose of comparability. I am not persuaded that the fact that the RXLEV comparisons both in band and between GSM bands which are made for normal reporting of handover in GSM itself, which are common general knowledge, would make it obvious over Losh to start making comparisons between different RATs in the phone for the purpose of reporting. It is only hindsight to see the reference to comparisons in Losh which would be understood in one context, and seek to turn that into a hint to make inter-RAT measurement comparisons in the phone for a different purpose.”
Essentiality and infringement
“111. The standard addresses the process of handover, including handover between GSM and other RATs. Section 3 of the April 2006 version contains an overview of the handover process. This explains (3.1) that measurements will be made by phones and reported to the BSS for assessment. The BSS will also measure the uplink performance for the phone being served and assess signal level interference on its idle traffic channels. Handover strategy (3.4) will be based on reported measurement results and various parameters set for each cell. An example of a basic algorithm is given in the standard. It is an example because the actual algorithms are not standardised. Section 8 of the standard deals with radio link measurements to be used in the handover process. Section 8.1 deals with signal level. Sections 8.1.2 - 8.1.4 deal with GSM and section 8.1.5 deals with other RATs. The relevant other RAT is UTRAN FDD.
112. In GSM the RMS received signal level is measured. In GSM the signal level is RXLEV. Section 8.2 deals with signal quality. In GSM received signal quality is RXQUAL. Section 8.4 deals with measurement reporting. There are two types of measurement reports - ‘normal’ and ‘enhanced’. Section 9 Table 2 sets out the control parameters used in handover.
114. In the context of a potential handover from GSM to UMTS, the serving cell will be a GSM cell and so the phone will be measuring RXLEV and RXQUAL on the GSM serving cell. The neighbouring cells may be GSM or UMTS cells. In the case of neighbouring GSM cells, the phone will be measuring RXLEV and, in the case of neighbouring UMTS FDD cells, the phone will measure RSCP and Ec/No.
116. The two kinds of measurement reports, normal and enhanced are sent on the SACCH. The structure of normal and enhanced reports is quite different. As mentioned above, in addition to reporting measurements from the serving cell, the ‘normal’ report provides the RXLEV values for the six neighbouring GSM cells with the highest RXLEV. The enhanced measurement report is organised very differently. There is a neighbour cell list which places the neighbouring cells in order. … The important things are, first, that the enhanced report is based on a list of neighbouring cells which both the phone and the BSS know. That means there is no need to send cell identifiers because the placing of data in the report acts as a key to indicate which cell the reported value relates to. The other important thing is that in the enhanced report measurement values are reported in a 6 bit format. That applies whether the values are RXLEV from a GSM cell or whatever measurements are being reported from a UMTS cell.
117. For the relevant kind of UMTS (UTRAN FDD) the standard requires the measurement of RSCP and Ec/No for the neighbour cells. Although two values are measured only one is reported. Which one is to be reported is set by a parameter called FDD_REP_QUANT. The standard states (8.1.5) that the measured value which is to be reported ‘shall replace RXLEV in the measurement reports’. So in the 6 bit fields for RXLEV described above, if a cell being reported is a UMTS cell the 6 bits will be used to report a value of RSCP or Ec/No as the case may be.
119. In relation to RSCP there are a number of points to note. The encoding is similar to but not the same as the encoding of RXLEV. The increments are the same (1dBm). For RXLEV (without SCALE) the integer zero represents less than -110 dBm whereas for RSCP it represents less than -115 dBm. So in a sense one scale is offset by 5dBm relative to the other. For RXLEV the integer 63 represents greater than -48 dBm whereas for RSCP measurements > -53 dBm is mapped to 63.
120. Enhanced measurement reporting in accordance with the April 2006 standard is dealt with in section 8.4.8. With enhanced measurement reporting, the phone is not limited to sending back measurement information for six neighbouring cells, but may send back information for a greater number of cells. In order to populate the enhanced measurement report, the various cells have to be ranked in order of reporting priority. That is done as follows:
i) Priority level 1: the relevant GSM cells with the highest reported value (RXLEV) are reported. The phone is told how many such cells may be reported, the maximum number is 3.
ii) Priority level 2: the cells to be reported work in the same way as priority level 1 but for cells in other GSM frequency bands.
iii) Priority level 3: the number of best valid cells whose reported values equal or exceed a pre-defined threshold in each supported other RAT, again up to a maximum of 3 per additional RAT. Where the other RAT is UTRAN FDD, then the non-reported value has to be equal or greater than a distinct pre-defined threshold. This second threshold can be disabled by being set to zero. For each RAT the cells with the highest reported values are reported.
iv) Priority level 4: the remaining valid GSM cells and valid cells of other RATs are reported as long as the cells pass the relevant threshold for that RAT. Within this level, the reporting priority for UTRAN FDD cells is based upon RSCP even if Ec/No is reported and the non-reported value has to be equal or greater than the pre-defined threshold.
i) if there are spaces unfilled within each priority level, those spaces are to be left over for the lower-prioritised cells; and
ii) if there is not enough space in the report for all valid cells, then the cells that shall be reported are those with the highest sum of the reported value and the parameter XXX_REPORTING_OFFSET.
122. Thus within priority levels 1 to 3, the phone selects cells within each RAT or band entirely independently of the measurement values obtained from other RATs or bands. The selection is done from a specific pool of cells (either GSM serving band; GSM non-serving band(s) or UMTS). Thresholds are applied to the reported values. Only values above the appropriate threshold are reported. Within the levels the ranking is in order of reported value.
123. At priority level 4 the pool of potential candidate cells is mixed as between GSM and UMTS (and other GSM bands and other RATs). In order to choose which cells to report at priority level 4 the encoded measured values are compared with each other. So the 6 bit integer encoded RXLEV value for a GSM cell is compared to the 6 bit integer encoded RSCP value for a UMTS cell. The higher integer gets a higher priority. The comparison can be affected by offsets, which can be set separately for each kind of cell. At that priority level only candidates that meet the RAT-specific entry requirements can enter the pool - i.e. for UMTS the second threshold can be applied. Even if Ec/No is the value which is going to be reported, in order to assess priority it is the encoded RSCP value which is used in the comparison with other candidates.”
A B C D
“128. The first column A is the integer value in decimal of the binary encoding. A 6 bit number in decimal can be from zero to 63. That is how RXLEV and RSCP are encoded in the GSM standard as shown in the next two sections of the table, B and C. A 7 bit number could code for zero up to 127. In the UMTS standard RSCP uses a 7 bit format and codes up to the integer value 91. This is shown in section D.
129. Moving from the UMTS to GSM way of encoding RSCP, involves losing the 7th bit. In order to do that in GSM all measurements above -53 dBm are encoded as 63, whereas in UMTS integer 63 means -53 to -52 dBm and integers above 63 encode measurements up to more than -25 dBm.”
“if there is not enough space in the report for all valid cells, the cells shall be reported that has the highest sum of the reported value (RXLEV or as defined in subclause 8.1.5) and the parameter XXX_REPORTING_OFFSET for respective radio access technology/mode. Note that this parameter shall not affect the actual reported value. …”
As the judge explained in , paragraph 8.1.5 says that RSCP converted to 6 bit format is used.
“133. … its case was that the comparison between encoded integers representing values from different RATs at priority level 4 demonstrates that the RSCP measured value has been rendered directly comparable with the encoded RXLEV value by converting the UMTS measured value into a measurement value for the GSM system. The priority assessment at level 4 works by ranking UMTS and GSM cells on the same numerical scale (the scale from 0 to 63 shown above) and choosing the highest ranked values to report, with a further ability to introduce prioritisation via offsets. So, it is submitted, priority level 4 proves that the encoding of RSCP in the GSM standard, in the form in which it is reported to the GSM network, satisfies all the requirements for the conversion required by claim 1.
134. For example consider priority level 4 and assume first that the offsets are set at zero. Assume also that there are two candidate cells each of which has its reported value above the relevant threshold: a GSM cell with RXLEV of -64.5 dBm and a UMTS cell with RSCP of -70.5 dBm. The encoding in the standard renders these measured values into integer 46 for the GSM cell and 45 for the UMTS cell. At priority level 4 these numbers are directly compared and the GSM cell is given a higher priority. If there is only one more space in the enhanced report then the GSM cell will be reported with its value and not the UMTS cell.
135. Optis contends that priority level 4 is a scheme for reporting the best cells chosen by directly comparing converted measurement values. Thus the claimed conversion has been undertaken, and the overall method infringes the claim because it creates, uses and reports converted UMTS values.”
“136. … Apple agrees that in order to meaningfully compare the two values it is necessary for some conversion to take place, but contends that the necessary conversion is provided by the offsets, which are controlled by the network. Note that it is the values without the offsets which are reported. So Apple argues that while it is true that the values are converted in the phone for the purposes of direct comparison, using the offsets, nevertheless there is no reporting of the converted values because the values reported are the ones without the offsets which had been applied. Apple also submits that the fact that, when both offsets are zero (or equal to one another) a valid comparison can be made, is true as far as it goes, but is not meaningful. Rather it is like a stopped clock which still happens to be right twice a day.”
Thus Apple contended that it was the application of the offsets which converted the UMTS and GSM values so as to enable a meaningful comparison to be made between them in priority level 4.
“137. Optis argued that this is wrong. The offsets used at priority level 4 are there to allow the network to bias the results. However they are not what makes the values directly comparable. The fact the values can be compared in this stage at all, using offsets which are constants to adjust or bias the comparison, shows that the encoding schemes for the reported values of RXLEV and RSCP as mandated by the GSM standard are directly comparable and therefore shows that RSCP has been converted appropriately.
138. In my judgment Optis’s approach to this is the right one. I was not persuaded by Mr Simmons’ approach to this. The fact that the patent does give, as an example, an equation in which a constant offset is added to the RSCP to make it comparable to RXLEV does not mean that the existence of a method which allows constant offsets to be used for prioritisation between RATs (or frequency bands) proves that the values before those offsets were added were not comparable. They may or may not have been. Moreover using a constant offset is clearly not the only way of converting measurements in such a way as to make them comparable. Another way expressly disclosed is to use an offset which varies as a function of RSCP and another way, which does not involve offsets at all (or not really) is mapping measurements to appropriate integers. That is how it is done in this case. Further, the contention that the fact offsets are added in level 4 proves that before the offsets were added the numbers were not comparable simply does not follow as a matter of logic. Moreover, as Optis pointed out, part of the same offsetting process involves applying offsets to RXLEV measurements from different frequency bands of GSM. Those RXLEV measurements plainly were directly comparable, prior to the application of the offsets.”
i) On the one hand, the judge states that “the existence of a method which allows constant offsets to be used for prioritisation between RATs” does not prove that “the values before those offsets were added were not comparable”. On the other hand, the judge accepts that the values before the offsets were added “may or may not have been” comparable. Apple agree with the latter statement, and submit that it must follow that the existence of a method which allows constant offsets to be used for prioritisation between RATs does not prove that the values before those offsets were added were comparable.
ii) Apple agree that the Patent discloses in  that the offset may be variable rather than constant (see paragraphs 21-22 above). They point out the offsets in the standard are variable in that they are set by the network, as the judge correctly found later in the judgment. They submit that this does not demonstrate that the values are comparable before the offsets are added either: as the judge says, they may or may not have been.
iii) Apple accept that direct comparability can be achieved by mapping, as the temperature example discussed in paragraph 48 above illustrates, but submit that there is no evidence that the mapping of the UMTS values in the standard does this. Rather, it simply converts the format of the UMTS values from 7 bits to 6 bits.
iv) The judge goes on to say that “the contention that the fact offsets are added in level 4 proves that before the offsets were added the numbers were not comparable simply does not follow as a matter of logic”, but Apple submit that it is equally true to say that it does not prove that the numbers were comparable. As the judge himself says, they may or may not have been; and it was for Optis to prove that they were comparable.
v) As for RXLEV measurements from different frequency bands of GSM, Apple agree that these are directly comparable without offsets, but say that that is precisely because they are both GSM RXLEV values and neither is a UMTS RSCP measurement requiring conversion. Again, Apple submit that this does not show that the UMTS and GSM values can be directly compared without offsets.
“Another point is that the issue is about the effect of the scheme itself. I think that is the point of Apple’s analogy with the clock. I agree that the schemes by which the values are encoded need to make the values comparable or not, as a whole. Comparability does not exist if it is only present when offsets are set to certain values. But to be fair, Optis’s line of argument about starting by assuming the offset is zero is not meant to be that the values are only comparable with offsets set at zero.”
“I find as a fact that the encoding of the RSCP measurements from the UMTS RAT into the 6 bit integer values provided for in the GSM standard produces a set of values which are directly comparable to a set of RXLEV values in GSM. That is why they are comparable whatever values are selected for the offsets. The offsets allow the operator to adjust what the result would be in a given case but they are not what makes the encoding schemes themselves comparable in the first place.”
Lord Justice Warby:
Lord Justice Newey: