Rb. Den Haag, 18-10-2017, nr. C/09/514186 / HA ZA 16-805

Philips is houdster van octrooien die zij essentieel acht voor de technische standaarden UMTS8.(3G) en LTE9.(4G) voor mobiele communicatie. Philips heeft bij de standaardisatie-organisatie ETSI10.deze octrooien als essentieel aangemeld, en heeft zich er schriftelijk toe verbonden deze octrooien op eerlijke, redelijke en niet-discriminerende (FRAND) voorwaarden in licentie te geven, overeenkomstig ETSI’s IPR Policy.

Bij brief van 21 november 2013 heeft Philips haar UMTS- en LTE-octrooiportfolio en licentieprogramma bij Asus onder de aandacht gebracht, zich daarbij op het standpunt stellend dat Asus diverse mobiele communicatie-apparaten fabriceert of verhandelt die inbreuk maken op één of meer van haar UMTS/LTE-octrooien. Vervolgens hebben diverse besprekingen tussen partijen plaatsgevonden. Bij brief van 21 september 2015 heeft Philips aan Asus een concept-licentieovereenkomst gezonden. Een licentieovereenkomst is niet tot stand gekomen.

Eind 2015 is Philips inbreukprocedures gestart bij deze rechtbank ter zake haar octrooien EP 525 (deze zaak), EP 1 440 511 (EP 511) en EP 1 685 659 (EP 659)11.. Deze octrooien zijn aangemeld als essentieel voor de zogenaamde HSPA12.-optie binnen de UMTS-standaard, waarmee een snelle dataoverdracht kan worden gerealiseerd (ook wel aangeduid met 3.5G of 3G+).

Philips heeft een in het Engels gestelde technische inleiding op de in de octrooien aan de orde zijnde UMTS-technologie overgelegd die als volgt luidt:

UMTS Primer

UMTS history

1. In the early 1990’s, the ‘Global System for Mobile communications’ (GSM) has been deployed. GSM is one of the second generation (2G) networks for mobile communications. Despite its enormous success, there was a need for a global standard for the next cellular developments which could provide the user with higher data rates.

2. With this in mind, the ‘International Telecommunication Union’ (ITU) started the process of defining concepts for third generation (3G) systems. This was referred to as ‘International Mobile Telecommunications 2000’ (IMT-2000). In order to implement the requirements defined by IMT-2000, in November 1999 the ITU formally adopted specifications for the ‘Universal Mobile Telecommunications System’ (UMTS) developed by 3GPP as part of the IMT-2000 family of standards.

3. Since then, the 3GPP consortium ‘Third Generation Partnership Project’ has been responsible for the maintenance and further evolution of the UMTS specifications. In Europe, the relevant standards organisation is the ‘European Telecommunications Standards Institute’ (ETSI), which is a partner of 3GPP.

4. After the first release of the UMTS Specifications in 1999 (Release 99), a number of further releases followed, including the introduction of ‘High Speed Downlink Packet Access’ (HSDPA) in Release 5 (2002) and ‘High Speed Uplink Packet Access’ (HSUPA) in Release 6 (2004). HSDPA and HSUPA are commonly referred to together as ‘High Speed Packet Access’ (HSPA).

5. The introduction of the HSDPA- and HSUPA-protocols significantly increased the maximum data transmission speeds available, allowing users to download and upload data (such as internet pages and pictures) much more quickly than before.

UMTS network

6. The UMTS network consists of three principal interacting entities: the Core Network (CN), the UMTS Terrestrial Radio Access Network (UTRAN) and the User Equipment (UE).

7. The CN is the entity that interfaces with external networks, including the public phone network, other cellular telecommunications networks and the internet. The UTRAN is the radio access network. It contains base stations (BS) (in UMTS called ‘Node B’s) that are equipped to send and receive radio signals. Via these radio signals, a base station is able to communicate with a mobile station (MS) (in UMTS called ‘User Equipment’ or ‘UE’), such as a mobile telephone. A base station typically serves a particular geographical area, commonly referred to as a “cell” (it may also control more than one cell). The UTRAN also interfaces with the CN and thus forms a “bridge” between the UE and the CN.

8. The UMTS network is schematically shown below:

CDMA

9. In mobile communications systems, such as GSM and UMTS, the uplink and downlink transmissions (i.e. from mobile station to base station and from base station to mobile station, respectively) are typically distinguished by using different radio frequency bands or different timeslots.

10. One of the main differences between GSM and UMTS is the manner in which the transmissions of different mobile stations are distinguished from one another.

11. GSM makes use of ‘Time Division Multiple Access’ (TDMA). In this method, different mobile stations are instructed to “listen” to transmissions from the base station (and send transmissions to the base station) only during different predetermined timeslots. Thus, transmissions associated with different mobile stations are separated in time.

12. The most wide-spread version of the UMTS-radio interface (often referred to as W-CDMA) uses ‘Code Division Multiple Access’ (CDMA). In CDMA, the transmissions of the different mobile stations occupy the same time slots and the same frequencies, but are separated from one another through the use of codes. Each mobile station has one or more unique codes (at least within one cell), which enables the mobile station to only “listen” to the transmissions that are specifically intended for this mobile station.

13. CDMA thus allows multiple transmissions on the same frequency and at the same time, which leads to a more flexible use of transmission resources, and in several respects to a simpler implementation than TDMA. Consequently, an important increase in efficiency can be achieved resulting in greater network capacity at a reasonable cost.

UMTS channels

Introduction

14. The radio access network of UMTS (the UTRAN) uses various channels that allow the transmission of data in the uplink direction (from mobile station to base station), in the downlink direction (from base station to mobile station) or in both directions.

15. These channels include dedicated channels and shared channels.

16. A dedicated channel is a channel which is assigned to one specific mobile station:

17. A shared channel may be used by more than one mobile station:

18. Data and control signals are processed by software arranged in layers. Channels are defined for passing data and control signals between the layers. These channels are referred to in the UMTS Specifications as logical channels, transport channels and physical channels depending on their level in the hierarchy.

19. The data and control signals to be transmitted are processed first at the higher layers and passed via the channels to lower layers until finally transmitted via the physical layer of the radio interface. As is illustrated below, logical channels are defined for passing data and control signals within Layer 2 of the software stack. Multiple logical channels are defined for different types of data, such as user data, hi-speed user data, paging control signals, broadcast control signals etc.

20. Transport channels are one level lower in the hierarchy and are defined for passing data and control signals to Layer 1 of the software stack. Each transport channel is associated with one or more logical channels and supplements the associated logical channel(s) by adding signals that define the transport requirements, such as error coding and signal quality information. Physical channels are lowest in the hierarchy. A physical channel may be associated with one or more transport channels (some physical channels have no associated higher level channels but only carry low-level signals). For transmitting, a physical channel supplements the associated transport channel(s) by adding signals that define the physical resources for the transmission, such as frequencies, codes, and power level.

21. When receiving a transmission, the received data and control signals are processed at the lower layers first and passed via the channels to higher layers.

22. A correspondence referred to as “mapping” is established between associated logical channels, transport channels and physical channels so that data transmission can be carried out in accordance with the requirements defined at each level of the hierarchy.

23. Below is an overview of the various logical-, transport- and physical channels and their “mapping”.

UMTS (Release 99)

24. Amongst the physical channels introduced in UMTS (Release 99) are the DPCCH and the DPDCH – which are both “Dedicated Physical Channels” (DPCH) -:

 Dedicated Physical Control Channel (DPCCH)

The DPCCH is a dedicated channel that carries control information such as power control commands, i.e. commands that instruct the mobile station or the base station to increase or decrease its transmission power (see below). Different DPCCHs may be defined for uplink and downlink transmission. The DPCCH is always configured when a radio connection is established between a mobile station and a base station (i.e. when the mobile station is in contact with a base station). This is even the case when there is no actual data being transmitted (i.e. when the user is not actively using his mobile telephone).

 Dedicated Physical Data Channel (DPDCH)

The DPDCH is a dedicated channel that transfers data, such as speech or video data. Different DPDCHs may be defined for transmission in each of the uplink and the downlink directions. Unlike the DPCCH, the DPDCH is only configured when actual data transmission occurs between a base station and a mobile station (i.e. when the user is actively using his mobile telephone). In that case, several DPDCHs can be configured at the same time.

HSDPA (Release 5)

25. In 2002, the HSDPA- (“High Speed Downlink Packet Access”) protocol was introduced. HSDPA is a technology for high speed downloading, i.e. from the base station to the mobile station. The protocol is built onto the existing UMTS technology and is aimed at providing increased data transfer speeds.

26. To enable the increase in data transfer speed, it was vital to make most efficient use of the available network resources, such as transmission frequencies and time. In order to achieve this, a number of additional channels were introduced under the HSDPA-protocol.

27. Most of these newly introduced channels are shared channels. The reason for this is that downloading typically does not involve continuous data transmission, but intensive data transmission for a short period of time (bursty), i.e. only when a mobile station needs new data from a base station (for example, when the user requests to view a webpage on his mobile). Assigning a dedicated channel to each mobile station for such data transmissions would result in inefficient use of the available capacity, hence the use of shared channels.

28. The newly added shared physical channels in HSDPA include:

 High Speed Physical Downlink Shared Channel (HS-PDSCH)

The HS-PDSCH is a downlink channel that is shared between multiple mobile stations. The channel is used to transmit data from the base station to the mobile station at a high transmission rate, such as internet pages requested by the mobile station.

 Fractional Dedicated Physical Control Channel (F-DPCH)

The F-DPCH is a shared downlink channel that is used by the base station to transmit control information to the mobile station during HSDPA transmission, such as power control commands (see below).

 High Speed Shared Control Channel (HS-SCCH)

The HS-SCCH is a shared downlink channel that is used by the base station to transmit control information to the mobile station that is specifically related to HS-PDSCH transmission. The control information includes, for example, information to indicate to a mobile station that it is scheduled to receive data from a base station.

29. Apart from the newly introduced shared channels, Release 5 of the UMTS Specifications also introduced a new dedicated channel, i.e. the HS-DPCCH.

 High Speed Dedicated Physical Control Channel (HS-DPCCH)

The HS-DPCCH is a dedicated uplink channel that carries feedback information from a mobile station to a base station. This feedback information includes ACK/NACK signals with respect to a previous HS-PDSCH transmission (see below).

HSUPA (Release 6)

30. In 2004, the HSUPA- (“High Speed Uplink Packet Access”) protocol was introduced. HSUPA is a technology for high speed uplink transmission, i.e. from the mobile station to the base station. Like HSDPA, also the HSUPA-protocol is built onto the existing UMTS technology and is aimed at providing increased data transfer speeds. HSUPA allows, for example, faster uploading of pictures or videos made by the user with his mobile telephone.

31. The newly added (physical) channels in HSUPA include the following dedicated channels:

 Enhanced Dedicated Physical Data Channel (E-DPDCH):

The E-DPDCH is used to transmit user data to the base station

 Enhanced Dedicated Physical Control Channel (E-DPCCH)

The E-DPCCH carries data specifically related to E-DPDCH transmission. The data includes information necessary for a base station to decode the E-DPDCH data.

ARQ system

32. The uplink and downlink transmissions in a wireless communication system, such as UMTS, are susceptible to error introduced during transmission. In order to mitigate the effect of errors in the transmitted data, various error detection/correction mechanisms are used in UMTS. One of these mechanisms is the so-called “Automatic Repeat reQuest” (ARQ) system.

33. In the ARQ system, a mobile station determines whether errors are present in the data packets that it received from a base station and informs the base station accordingly. For this purpose, a mobile station sends a positive-acknowledgement (ACK) signal back to a base station when it has received data from the base station correctly. On the other hand, it sends a negative-acknowledgement (NACK) signal to the base station when it did not receive the data correctly. This allows all or some of the packet contents to be re-transmitted, which enables correction of the erroneous data.

Transmit power control

34. Power control relates to the power with which radio signals are being sent in a wireless communication system. Power control is performed on the signals in the uplink direction and on the signals in the downlink direction.

Uplink power control

35. It is important that a base station receives signals from all mobile stations in the cell at approximately the same power level regardless of their respective distances from the base station. Otherwise, the signal from a mobile station that is relatively far away from the base station may be “swamped” by the signal from a mobile station that is closer to the base station.

36. This is shown in the diagram below, in which mobile station A is relatively far away from the base station and mobile station B is closer to the base station. Without power control the risk exists that the signal from mobile station A is “swamped” by the signal from mobile station B.

37. This is of particular relevance in UMTS. As explained above, UMTS allows more than one mobile station to communicate with a base station on the same frequency and at the same time. Signals from different mobile stations are thus more likely to interfere with each other.

38. Against this background, it is of importance to control the transmit power of each mobile station in order to limit this undesirable interference.

39. In order to achieve this, the base station measures the power level of the signal that it receives from the mobile station and instructs the mobile station to adjust its power level, i.e. to reduce or to increase its transmission power (see diagram above). The instruction is typically provided in the form of a “Transmit Power Control” (TPC) command, which in the case of uplink power control, is sent by the base station to the mobile station via a downlink control channel.

Downlink power control

40. Also with respect to downlink transmissions, the power level should be controlled effectively. On the one hand, the transmission power should be strong enough for the mobile station to be able to decode the received signal. On the other hand, the transmission power of the signal sent by the base station should not be too high, as this may cause interference in neighbouring cells. See the diagram below:

41. To this end, the mobile station measures the signal received from the base station. Also here, the instruction to increase or decrease the power level is typically provided in the form of a “Transmit Power Control” (TPC) command. To control the downlink power, the TPC command is sent by the mobile station to the base station via an uplink control channel.

EP 525

EP 525 met de titel “Radio Communication System”, is verleend op 9 mei 2012 op een aanvraag van 15 oktober 2002, met een beroep op prioriteitsdata 19 oktober 2001 (GB 0125175) en 5 november 2001 (GB 0126421). EP 525 kent 15 conclusies die in de oorspronkelijke Engelse taal als volgt luiden:

1.A radio communication system having a communication channel for the transmission of data packets from a primary station (100) to a secondary station (110) the secondary station having receiving means for receiving a data packet (202) and acknowledgement means for transmitting a signal to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types (204,206) wherein the acknowledgement means is arranged to select the power level at which the signal is transmitted depending on its type and in dependence on an indication of the power level at which each type of signal is transmitted, the indication being signaled from the primary station to the secondary station.

2.A system as claimed in claim 1, characterized in that the available signal types include signals indicating positive and negative acknowledgements.

3.A system as claimed in claim 2, characterized in that the available signal types further include a revert signal indicating a request for retransmission of a packet received before the packet just received.

4.A system as claimed in claim 3, characterized in that the revert signal is identical to the negative acknowledgement signal but is transmitted at a higher power.

5.A primary station (100) for use in a radio communication system having a communication channel for the transmission of data packets from the primary station to a secondary station (110), wherein means are provided for transmitting a data packet to the secondary station and for receiving a signal from the secondary station to indicate the status of a received data packet (202), which signal is selected from a set of at least two available signal types and is transmitted with a power level selected depending on its type (204,206), and wherein means are provided for signaling to the secondary station an indication on how the power level at which the secondary station transmits each type of signal depends on the type of the signal.

6.A primary station as claimed in claim 5, characterized in that means are provided for determining the type of the received signal depending on its received power level.

7.A primary station as claimed in claim 5 or 6, characterized in that the indication comprises an instruction to the secondary station to transmit at least two types of signals at different powers.

8.A primary station as claimed in claim 5 or 6, characterized in that the indication informs the secondary station of the transmission power that it should use for at least one of the available signal types.

9.A primary station as claimed in claim 5, 6 or 8, characterized in that the indication informs the secondary station of a required power difference between two different types of signals.

10.A secondary station (110) for use in a radio communication system having a communication channel for the transmission of data packets from a primary station (100) to the secondary station, wherein receiving means are provided for receiving a data packet (202) from the primary station and acknowledgement means are provided for transmitting a signal to the primary station (204, 206) to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, wherein the acknowledgement means is arranged to select the power level at which the signal is transmitted depending on its type and in dependence on an indication of the power level at which each type of signal is transmitted, the indication being signaled from the primary station to the secondary station.

11.A secondary station as claimed in claim 10, characterized in that the signal types include signals indicating positive and negative acknowledgements and in that the acknowledgement means transmits negative acknowledgements at a higher power than positive acknowledgements.

12.A secondary station as claimed in claim 11, characterized in that the acknowledgement means only transmits negative acknowledgements at a higher power than positive acknowledgements if a time-averaged ratio of positive acknowledgements to negative acknowledgements is greater than a predetermined value.

13.A secondary station as claimed in claim 10 or 11, characterized in that the available signal types include signals conveying information relating to prevailing radio conditions other that the status of the received data packet.

14.A secondary station as claimed in claim 10, characterized in that the indication informs of an offset value of the power level at which the signal is transmitted.

15.A method of operating a radio communication system having a communication channel for the transmission of data packets from a primary station (100) to a secondary station (110) the method comprising the secondary station receiving a data packet (202) and transmitting an acknowledgement signal (204,206) to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, the method comprising selecting the power level at which the signal is transmitted depending on its type and in dependence on an indication of the power level at which each type of signal is transmitted, the indication being signaled from the primary station to the secondary station.

In de onbestreden Nederlandse vertaling luiden deze conclusies:

1. Radiocommunicatiesysteem met een communicatiekanaal voor de overdracht van gegevenspakketten van een primair station (100) naar een secundair station (110), waarbij het secundaire station ontvangmiddelen heeft voor het ontvangen van een gegevenspakket (202) en bevestigingsmiddelen voor het overdragen van een signaal naar het primaire station om de status van een ontvangen gegevenspakket aan te duiden, waarbij het signaal is gekozen uit een reeks van ten minste twee beschikbare signaaltypes (204, 206), waarbij het bevestigingsmiddel is ingericht om het vermogensniveau te kiezen waarbij het signaal wordt overgedragen afhankelijk van zijn type en afhankelijk van een aanduiding van het vermogensniveau waarbij elk type signaal wordt overgedragen, waarbij de aanduiding uit het primaire station naar het secundaire station wordt overgeseind.

2. Systeem volgens conclusie 1, met het kenmerk, dat de beschikbare signaaltypes signalen omvatten die positieve en negatieve bevestigingen omvatten.

3. Systeem volgens conclusie 2, met het kenmerk, dat de beschikbare signaaltypes verder een teruggekeerd signaal omvatten dat een vraag aanduidt voor heroverdracht van een pakket ontvangen vóór het pakket dat net werd ontvangen.

4. Systeem volgens conclusie 3, met het kenmerk, dat het teruggekeerde signaal identiek is aan het negatieve bevestigingssignaal, maar bij een hoger vermogen wordt overgedragen.

5. Primair station (100) voor gebruik in een radiocommunicatiesysteem met een communicatiekanaal voor de overdracht van gegevenspakketten uit het primaire station naar een secundair station (110), waarbij middelen worden voorzien voor het overdragen van een gegevenspakket naar het secundaire station en voor het ontvangen van een signaal

uit het secundaire station om de status van een ontvangen gegevenspakket (202) aan te duiden, waarbij het signaal is gekozen uit een reeks van ten minste twee beschikbare signaaltypes en wordt overgedragen met een vermogensniveau gekozen afhankelijk van zijn type (204, 206), en waarbij middelen worden voorzien voor het overseinen naar het secundaire station van een aanduiding over hoe het vermogensniveau waarbij het secundaire station elk type signaal overdraagt, van het type van het signaal afhangt.

6. Primair station volgens conclusie 5, met het kenmerk, dat middelen worden voorzien voor het bepalen van het type van het ontvangen signaal afhankelijk van zijn ontvangen vermogensniveau.

7. Primair station volgens conclusie 5 of 6, met het kenmerk, dat de aanduiding een instructie voor het secundaire station omvat voor het overdragen van ten minste twee types signalen bij verschillende vermogens.

8. Primair station volgens conclusie 5 of 6, met het kenmerk, dat de aanduiding het secundaire station op de hoogte stelt van het overdrachtsvermogen dat het zou moeten gebruiken voor ten minste één van de beschikbare signaaltypes.

9. Primair station volgens conclusie 5, 6 of 8, met het kenmerk, dat de aanduiding het secundaire station op de hoogte stelt van een vereist vermogensverschil tussen twee verschillende types signalen.

10. Secundair station (110) voor gebruik in een radiocommunicatiesysteem met een communicatiekanaal voor de overdracht van gegevenspakketten uit een primair station (100) naar het secundaire station, waarbij ontvangstmiddelen worden voorzien voor het ontvangen van een gegevenspakket (202) uit het primaire station en bevestigingsmiddelen worden voorzien voor het overdragen van een signaal naar het primaire station (204, 206) om de status van een ontvangen gegevenspakket aan te duiden, waarbij het signaal is gekozen uit een reeks van ten minste twee beschikbare signaaltypes, waarbij het bevestigingsmiddel wordt ingericht voor het kiezen van het vermogensniveau waarbij het signaal wordt overgedragen afhankelijk van zijn type en afhankelijk van een aanduiding van het vermogensniveau waarbij elk type signaal wordt overgedragen, waarbij de aanduiding van het primaire station naar het secundaire station wordt overgeseind.

11. Secundair station volgens conclusie 10, met het kenmerk, dat de signaaltypes signalen omvatten die positieve en negatieve bevestigingen aanduiden en dat het bevestigingsmiddel negatieve bevestigingen bij een hoger vermogen dan positieve bevestigingen overdraagt.

12. Secundair station volgens conclusie 11, met het kenmerk, dat het bevestigingsmiddel enkel negatieve bevestigingen bij een hoger vermogen dan positieve bevestigingen overdraagt, indien een tijdgemiddelde verhouding van positieve bevestigingen tot negatieve bevestigingen groter is dan een vooraf bepaalde waarde.

13. Secundair station volgens conclusie 10 of 11, met het kenmerk, dat de beschikbare signaaltypes transportinformatie met betrekking tot geldende radiovoorwaarden verschillend van de status van het ontvangen gegevenspakket omvatten.

14. Secundair station volgens conclusie 10, met het kenmerk, dat de aanduiding op de hoogte stelt van een offsetwaarde van het vermogensniveau waarbij het signaal wordt overgedragen.

15. Werkwijze voor het laten werken van een radiocommunicatiesysteem met een communicatiekanaal voor de overdracht van gegevenspakketten uit een primair station (100) naar een secundair station (110), waarbij de werkwijze omvat dat het secundaire station een gegevenspakket (202) ontvangt en een bevestigings-signaal (204, 206) naar het primaire station overdraagt om de status van een ontvangen gegevenspakket aan te duiden, waarbij het signaal is gekozen uit een reeks van ten minste twee beschikbare signaaltypes, waarbij de werkwijze het kiezen omvat van het vermogensniveau waarbij het signaal wordt overgedragen afhankelijk van zijn type en afhankelijk van een aanduiding van het vermogensniveau waarbij elk type signaal wordt overgedragen, waarbij de aanduiding van het primaire station naar het secundaire station wordt overgeseind.

In de beschrijving van EP 525 is onder meer opgenomen:

Technical Field

[0001] The present invention relates to a radio communication system and further relates to primary and secondary stations for use in such a system and to a method of operating such a system. While the present specification describes a system with particular reference to the Universal Mobile Telecommunication System (UMTS), it is to be understood that such techniques are equally applicable to use in other mobile radio systems.

Background Art

[0002] There is a growing demand in the mobile communication area for a system having the ability to download large blocks of data to a Mobile Station (MS) on demand at a reasonable rate. Such data could for example be web pages from the Internet, possibly including video clips or similar. Typically a particular MS will only require such data intermittently, so fixed bandwidth dedicated links are not appropriate. To meet this requirement in UMTS, a High-Speed Downlink Packet Access (HSDPA) scheme is being developed which may facilitate transfer of packet data to a mobile station at up to 4Mbps.

[0003] A conventional component of a packet data transmission system is an ARQ (Automatic Repeat reQuest) process, for handling data packets received in error. For example, consider downlink packet transmission from a Base Station (BS) to a Mobile Station (MS) in HSDPA. When the MS receives a data packet it determines whether the packet has been corrupted, for example using Cyclic Redundancy Check (CRC) information. It then transmits a codeword to the BS, with a first codeword used as an acknowledgement (ACK), to indicate that the packet was successfully received, and a second codeword used as a negative acknowledgement (NACK), to indicate that the packet was received but corrupted. Since packet transmission is typically intermittent, discontinuous transmission (DTX) is normally employed, so that nothing is transmitted by the MS unless a data packet has been received.

[0004] A problem with such an ARQ scheme is that the consequences of errors in the ACK and NACK are significantly different. Normally the BS would re-transmit a packet if a NACK were received. If the BS receives a NACK when a ACK was sent, then the packet is re-transmitted anyway, which only wastes a little system resource. If a NACK is sent, but received as a ACK, then no re-transmission is made. Without special physical layer mechanisms, this situation can only be recovered from by using higher layer processes, which adds delay and is a significant waste of system resources. Hence, the cost of an error in a NACK is much more serious than the cost of an error in a ACK.

[0005] In order to optimise system performance, it is desirable to control the relative probabilities of errors in decoding ACKs and NACKs. In one UMTS embodiment this is done by setting different detection thresholds at the BS, which requires the MS to transmit the ACK/NACK codeword with a specific power level (e.g. relative to uplink pilot power). This power level and the detection threshold can therefore be chosen to balance costs of ACK/NACK errors, interference generated by the MS, and battery power used by the MS. With DTX, the situation is a little more complex. However, the BS, as the source of the packet, is aware of when a ACK/NACK should be sent by the MS and it should therefore not normally be necessary to specifically detect the DTX state.

[0006] In our co-pending German patent application DE10132577 a physical layer mechanism for recovering from the case where the BS misinterprets a NACK as an ACK is disclosed. This mechanism makes use of an additional codeword, REVERT, which informs the BS that the MS has received a transmission of a new packet when it was expecting retransmission of the previous packet. In a variation on this scheme two REVERT codewords are used, to provide in addition a NACK or an ACK in respect of the new packet.

[0007] US 4888767 discloses a radio communication system having a communication channel for the transmission of data packets from a primary station to a secondary station, the secondary station having receiving means for receiving a data packet and acknowledgement means for transmitting a signal to the primary station to indicate the status of a received data packet. In more details, the secondary station transmits a repeat request signal to indicate that the status of the data packet is erroneous, and does not transmit a signal if the status of the data packet is correct.

[0008] US 5517507 discloses subject matter similar to US 4888767. In more details, a NACK/ACK signal is transmitted, a NACK signal being represented by an energy burst and an ACK signal being no burst (which is equivalent, according to the examiner, to the transmission of a signal having a power level of zero).

Disclosure of Invention

[0009] An object of the present invention is to improve the efficiency of a packet data transmission system.

[0010] According to a first aspect of the present invention there is provided a radio communication system having a communication channel for the transmission of data packets from a primary station to a secondary station, the secondary station having receiving means for receiving a data packet and acknowledgement means for transmitting a signal to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, wherein the acknowledgement means is arranged to select the power level at which the signal is transmitted depending on its type.

[0011] By transmitting different acknowledgement signals at different power levels, the probability of the primary station correctly interpreting signals of different types can be manipulated to improve total system throughput and capacity. In one embodiment negative acknowledgements are transmitted at a higher power level than positive acknowledgements to increase the probability of the primary station retransmitting a data packet when necessary. In another embodiment an additional revert signal type is provided, which requests the primary station to retransmit a data packet initially transmitted prior to the current data packet and which was not correctly received. The revert signal may be identical to the negative acknowledgement signal but transmitted at a higher power level.

(…)

[0023] It is likely for most applications that DTX would be applied for most of the time, given the typically intermittent nature of packet data transmission. In addition, for a well configured system, NACKs 204 should be sent significantly less often than ACKs 206. Hence, in a system made in accordance with the present invention a NACK 204 is transmitted at a higher power level than an ACK 206. This power offset is advantageous because it reduces the error probability for the NACK 204 without increasing the power transmitted for the ACK 206. It is particularly advantageous if the probability of a MS 110 missing a packet is very small, so there is no need to consider optimum setting of BS detection thresholds to differentiate NACK from DTX. Hence, any given error performance targets could be achieved with minimum average power transmitted by the-MS 110.

[0024] It will be recognised that if a MS 110 is transmitting more NACKs 204 than ACKs 206, this proposed strategy would result in an increase in average uplink interference rather than the desired decrease. Therefore, in one embodiment of the present invention, the MS 110 is forbidden from applying the power offset unless it has previously positively acknowledged more than a certain proportion of packets (e.g. 50%). This prevents the power offset from causing an undue increase in uplink interference in poor downlink channel conditions.

[0025] In another embodiment of the present invention, the relative power levels of ACKs 206 and NACKs 204 are modified depending on the proportion of ACKs and NACKs sent. For example, this adaptation could be controlled by a time-weighted average of the proportion of ACKs 206 sent. The detection threshold at the BS 100 could adapted in a similar way based on the proportion of ACKs 206 received. It is apparent that such processes would converge, even in the presence of errors.

[0026] In another embodiment of the present invention, instead of being predetermined the ACK/NACK power offset (or maximum offset) could be signalled by the BS 100 depending on the type of service being conveyed to the MS 110 via the data packets 202. For example, in a real-time streaming service with strict timing constraints, a packet which is lost due to a wrongly-detected NACK 204 may simply be ignored by the application if there were not enough time even for a physical layer retransmission. However, for a data service where correct receipt of packets was essential, an ACK/NACK power offset could be signalled. The offset might also be useful in streaming services with slightly less strict timing requirements, where there was insufficient time for a higher-layer retransmission, but a NACK power offset would increase the chance of an erroneous packet being rectified by means of fast physical layer retransmission. It would therefore be beneficial to allow a different offset value to be signalled for each downlink transport channel.

[0027] This approach can be further developed by assigning different offset values to the ACK/NACKs for different packets of the same transport channel. For example, in an MPEG stream it is very important to receive the I-frames correctly to avoid errors in subsequent frames. An ACK/NACK power offset could therefore be applied for acknowledgement of packets containing I-frame data while a smaller (or zero) offset is applied for acknowledgement of other packets. Some special signalling could be required, such as a physical layer tag or a particular sequence number on the packets 202, to indicate which packets contained the I-frame data.

[0028] In a further development of this approach, other information, such as channel quality, could be signalled by the use of different codewords in the data field reserved for ACK/NACK messages, as disclosed in our co-pending International patent application WO 02067618 (applicant's reference PHGB 010069). In general it is likely that there are different costs of errors in detecting the different information possibilities. Therefore, there could be different power levels applied to the transmission of different subsets of codewords. Furthermore, this approach could be combined with design of the codeword distances to reach specified performance targets. As an example, if NACK is 0000, then ACK might be 1110, and sending ACK together with an indication of high channel quality might be 1111.

[0029] In one preferred embodiment, particularly suitable for UMTS HSDPA, the ACK/NACK power offset used by the MS 110, as well as the ACK power level would be determined by higher layer signalling from the network. Alternatively, the offset could be signalled using a single information bit, signifying "no offset" (i.e. equal transmit power for ACK 206 and NACK 204) or "use offset", signifying the use of a pre-determined value of power offset. More signalling bits could be used to indicate a larger range of values of offset.

[0030] The BS 100 (knowing the power levels used by the MS 110) would use a detection threshold adjusted to optimise system performance (although the BS 100 would not necessarily have to know the power levels used by the MS 110, as a "neutral" threshold could be set based on the received uplink pilot information). An optimised threshold could be set by the Radio Network Controller (RNC) or other means.

(…)

[0040] In the second embodiment, DTX and NACK sent with same (zero) - power, while REVERT sent as a different codeword to ACK but with the same power. (…)

[0048] In general, the power levels at which the ACK/NACK and/or REVERT commands are transmitted may be adjusted in order to achieve a required level of reliability. These power levels could be controlled by messages sent from the BS 100 to the MS 110. These could specify the power level relative to the pilot bits on the uplink dedicated control channel, or relative to the current power level for the channel quality metric. In the case of the dedicated control channels of one MS 110 being in soft handover with more than one BS 100 the power of the uplink dedicated control channel is not likely to be optimal for all the BSs 100 involved. Therefore, a different power level, preferably higher, may be used for sending the ACK/NACK and/or REVERT commands. This power difference could be fixed, or determined by a message from a BS 100. When the transmission of ACK/NACK and/or REVERT is directed to a particular BS 100, the power level may be further modified to take into account the quality of the radio channel for that transmission. For example, if the best radio link from the active set is being used, the power level may be lower than otherwise.

(…)

Bij EP 525 horen de volgende figuren:

Philips heeft in aanvulling op de technische inleiding op UMTS (r.o. 2.4), in randnummers 9 t/m 20 van de dagvaarding, de navolgende toelichting gegeven op de in EP 525 neergelegde techniek:

9. In mobiele telecommunicatiesystemen worden zgn. basisstations (BS) gebruikt. Een basisstation kan communiceren met verschillende zgn. mobiele stations (MS), wanneer deze zich binnen het bereik van het basisstation bevinden. In het Octrooi worden de basisstations als “primaire stations” aangeduid en de mobiele stations als “secundaire stations”.

10. Het Octrooi toont in Figuur 1 een voorbeeld van een communicatiesysteem met één basisstation 100 (links in de figuur) en twee mobiele stations 110 (rechts in de figuur) [tekst en kleur toegevoegd; adv.]:

11. Een basisstation en een mobiel station communiceren met elkaar door middel van radiosignalen, waarbij de communicatie in beide richtingen verloopt. Dat gebeurt via een uplink-verbinding (transmissie van MS naar BS) of via een downlink-verbinding (transmissie van BS naar MS). In de bovenstaande figuur is de downlink-verbinding aangeduid met verwijzingscijfer 122 en de uplink-verbinding met verwijzingscijfer 124.

11. Met betrekking tot de te verzenden informatie, kan een onderscheid worden gemaakt tussen twee typen informatie, te weten:

13. Enige tijd geleden ontstond de behoefte om grotere hoeveelheden data (zoals internetpagina’s e.d.) in mobiele communicatienetwerken te verzenden, met name in de downlink-richting. Voor dit doel werd in 2002 het hiervoor genoemde HSDPA-protocol geïntroduceerd als onderdeel van de UMTS-technologie (vgl. Productie EP2 [dit is de hiervoor weergegeven primer, zie r.o. 2.4, toev. rechtbank]). Om HSDPA te ondersteunen, werden de volgende fysieke kanalen gedefinieerd13.:

14. Het opsporen en elimineren van fouten in de gebruikersgegevens speelt een belangrijke rol in het HSDPA-protocol. De datapakketten bevatten daartoe additionele bits die het mobiele station in staat stellen om direct na ontvangst van het datapakket, fouten te detecteren. Dit kan worden gedaan door middel van een zgn. ‘Cycle Redundancy Check’ of ‘CRC’ (Octrooi, blz. 2, regels 20-21). Op basis hiervan is het mobiele station in staat om vast te stellen of het datapakket goed of met fouten is ontvangen en kan het aan het basisstation vervolgens een positief of negatief bevestigingssignaal verzenden.

14. Is het pakket goed ontvangen, dan stuurt het mobiele station aan het basisstation een zgn. ACK (= Acknowledgement) signaal. Indien het pakket met fouten is ontvangen, dan stuurt het mobiele station aan het basisstation een NACK (= Negative Acknowledgement) signaal (Octrooi, blz. 2, regels 21 – 24). Dit proces wordt ook wel aangeduid met de term “ARQ” (= Automatic Repeat reQuest) (Octrooi, blz. 2, regels 18-20).

14. De geoctrooieerde uitvinding ziet op het probleem dat het basisstation de bevestigingssignalen mogelijk verkeerd interpreteert. De gevolgen van een dergelijke onjuiste interpretatie zijn verschillend al naar gelang het bevestigingssignaal een acknowledgement (ACK) of een negative acknowledgement (NACK) is.

14. Wanneer het mobiele station een ACK aan het basisstation verzendt (ter bevestiging van de goede ontvangst van het datapakket) en het basisstation interpreteert dit signaal als een NACK, dan zal het basisstation het betreffende datapakket ten onrechte opnieuw aan het mobiele station verzenden. Dat resulteert in onnodig gebruik van systeem resources. Een groter probleem ontstaat wanneer het basisstation een door het mobiele station verzonden NACK interpreteert als een ACK. In dat geval neemt het basisstation namelijk ten onrechte aan dat een foutloze ontvangst van het datapakket heeft plaatsgevonden en zal het zonder aanvullende maatregelen geen vervangend datapakket aan het mobiele station verzenden (hoewel het door het mobiele station ontvangen datapakket dus in werkelijkheid ‘corrupt’ was). Vgl. blz. 2, regels 27-31 van het Octrooi:

“A problem with such an ARQ scheme is that the consequences of errors in the ACK and NACK are significantly different. Normally the BS would re-transmit a packet if a NACK were received. If the BS receives a NACK when an ACK was sent, then the packet is re-transmitted anyway, which only wastes a little system resource. If a NACK is sent, but received as an ACK, then no re-transmission is made. Without physical layer mechanisms, this situation can only be recovered from by using higher layer processes, which adds delay and is a significant waste of system resources. Hence, the cost of an error in a NACK is much more serious than the cost of an error in ACK.”

18. Het doel van de geoctrooieerde uitvinding is om de efficiency van de transmissie van datapakketten te verbeteren (vgl. blz. 2, regel 55).

18. Dit doel wordt bereikt doordat het mobiele station volgens de uitvinding in staat is om het vermogensniveau van het te verzenden bevestigingssignaal (e.g. ACK/NACK) te selecteren op basis van het signaaltype (ACK of NACK) en op basis van een van het basisstation ontvangen indicatie van het vermogensniveau van het betreffende signaaltype. Dit maakt het mogelijk om het vermogensniveau voor elk type bevestigingssignaal (ACK of NACK) aan te passen en de kans op correcte interpretatie van dit signaal door het basisstation te verhogen. Vgl. bijvoorbeeld blz. 3, regels 4-5:

“By transmitting different acknowledgement signals at different power levels, the probability of the primary station correctly interpreting signals of different types can be manipulated to improve total system throughput and capacity.”

20. Vgl. ook blz. 7, regels 49-52 van het Octrooi:

“In general, the power levels at which the ACK/NACK and/or REVERT commands are transmitted may be adjusted in order to achieve a required level of reliability. These power levels could be controlled by messages sent from the BS 100 to the MS 110. These could specify the power level relative to the pilot bits on the uplink dedicated control channel, or relative to the current power level for the channel metric.”

In haar pleitnota (randnrs. 12 tot en met 14) heeft Philips aan deze toelichting toegevoegd:

12. Om tot een optimale system performance te komen werd in de stand van de techniek gebruik gemaakt van drempelwaarden in het basisstation waarmee de kans op foutieve interpretatie van ACK en NACK kon worden gecontroleerd. Dat wordt beschreven in paragraaf [0005] van het Octrooi onder het kopje “Background Art”:

“In order to optimise system performance, it is desirable to control relative probabilities of errors in decoding ACKs and NACKs. In one UMTS embodiment this is done by setting different detection thresholds at the BS, which requires the MS to transmit the ACK/NACK codeword with a specific level (e.g. relative to uplink power level). This power level and the detection threshold can therefore be chosen to balance costs of ACK/NACK errors, interference generated by the MS, and battery power by the MS.” [onderstreping toegevoegd; adv.]

13. Zoals we hierna zullen zien, is dit ook de benadering in de stand van de techniek waarop ASUS zich beroept: zonder uitzondering wordt hierin voorgesteld om in het basisstation een drempelwaarde toe te passen, die zodanig is ingesteld dat met een zo laag mogelijk interferentie wordt voldaan aan gefixeerde ACK- en NACK- error rates

14. De geoctrooieerde uitvinding heeft als doel om de efficiency van de transmissiesystemen te verbeteren (vgl. paragraaf [0009]: “An object of the present invention is to improve the efficiency of a packet data transmission system.”). Kort gezegd, wordt hiertoe een systeem voorgesteld waarin het zendvermogen van het bevestigingssignaal kan worden aangepast al naar gelang het te verzenden bericht een ACK of een NACK is, en afhankelijk van een indicatie van het vermogensniveau van dat bericht die door het basisstation wordt overgeseind. Hierdoor is niet langer sprake van een gefixeerd systeem met vooraf vastgestelde error rates voor ACKs en NACKs; in de uitvinding kunnen ACK en NACK onafhankelijk van elkaar worden gevarieerd waardoor de kans op false ACKs en false NACKs van geval tot geval kan worden aangepast. Hierdoor wordt een zeer flexibel en efficiënt transmissiesysteem verkregen.

De CDMA2000-Standaard is een mobiele telefonie standaard die met name in Amerika en delen van Azië en Afrika wordt toegepast en die wordt gepubliceerd door de standaardisatie organisatie 3GPP2. In het tot deze standaard behorende document EVDO C.S0024 versie 2.0 van 27 oktober 2000 (GP24B, hierna: de EVDO standaard) is onder meer het navolgende opgenomen.

Op pag. 1-10 wordt een radiocommunicatiesysteem (Access Network) beschreven waarmee een mobiel station (Access Terminal) communiceert:

De EVDO standaard definieert een tweetal fysieke hoofdkanalen, het Forward Channel en het Reverse Channel. Het Forward Channel wordt verstuurd door het basistation (BS) naar het mobiele station (MS) en het Reverse Channel wordt in de omgekeerde richting verstuurd. Zowel het Forward Channel alsook het Reverse Channel omvat een aantal subkanalen, zoals getoond in figuren 1.5-1 en 1.5-2 van de EVDO Standaard.

In de EVDO Standaard verstuurt het BS datapakketten over het Forward Channel, meer in het bijzonder over het Forward Traffic Channel. Het versturen van datapakketten over de fysieke laag wordt bijv. beschreven in hoofdstuk 9.1.1:

3 9.1.1 Overview

4 The transmission unit of the physical layer is a physical layer packet. A physical layer

5 packet can be of length 256, 512, 1024, 2048, 3072, or 4096 bits. The format of the

6 physical layer packet depends upon which channel it is transmitted on. A physical layer

7 packet carries one or more MAC layer packets.

De EVDO Standaard schrijft tevens een Reverse Ack kanaal voor. Over dit kanaal verstuurt het MS positieve ACK bevestigingen en negatieve NACK bevestigingen. Deze ACK en NACK bevestigingen worden beschreven in paragraaf 9.2.1.3.3.4 op pag. 9-39 van de EVDO Standaard. In het bijzonder wordt hier beschreven dat het ACK kanaal door het MS (de “access terminal”) wordt gebruikt voor het informeren van het netwerk of een datapakket dat over het Forward Traffic Channel is verstuurd, al dan niet goed is ontvangen:

3 9.2.1.3.3.4 ACK Channel

4 The ACK Channel is used by the access terminal to inform the access network whether a

5 physical layer packet transmitted on the Forward Traffic Channel has been received

6 successfully or not. The access terminal shall transmit an ACK Channel bit in response to

7 every Forward Traffic Channel slot that is associated with a detected preamble directed to

8 the access terminal. The access terminal shall transmit at most one redundant positive

9 ACK in response to a Forward Traffic Channel slot that is detected as a continuation of the

10 physical layer packet that has been successfully received. Otherwise, the ACK Channel

11 shall be gated off.

12 The ACK Channel shall be BPSK modulated. A ‘0’ bit (ACK) shall be transmitted on the ACK

13 Channel if a Forward Traffic Channel physical layer packet has been successfully received;

14 otherwise, a ‘1’ bit (NAK) shall be transmitted. A Forward Traffic Channel physical layer

15 packet is considered successfully received if the FCS checks. For a Forward Traffic Channel

16 physical layer packet transmitted in slot n on the Forward Channel, the corresponding ACK

17 Channel bit shall be transmitted in slot n + 3 on the Reverse Channel (see Figure 9.2.1.3.1-

18 5 and Figure 9.2.1.3.1-6). The ACK Channel transmission shall be transmitted in the first

19 half of the slot and shall last for 1024 PN chips as shown in Figure 9.2.1.3.1-5 and Figure

20 9.2.1.3.1-6. The ACK Channel shall use the Walsh channel identified by the Walsh function

21 W84 and shall be transmitted on the I channel.

Op pag. 9-25 van de EVDO Standaard wordt vermeld dat het vermogen van het ACK kanaal (waarover de bevestigingsberichten worden verstuurd) wordt bepaald door een aanduiding van het vermogenniveau “ACKChannelGain”:

6 During the transmission of the ACK Channel, the power of the ACK Channel relative to that

7 of the Pilot Channel shall be as specified by ACKChannelGain, where ACKChannelGain is

8 public data of the Forward Traffic Channel MAC Protocol.

De EVDO standaard vermeldt over de AckChannelGain op pag. 6-58 het volgende:

26 AckChannelGain The access network shall set this field to the ratio of the power level

27 of the Ack Channel (when it is transmitted) to the power level of the

28 Reverse Traffic Pilot Channel expressed as 2’s complement value in

29 units of 0.5 dB. The valid range for this field is from –3 dB to +6 dB,

30 inclusive. The access terminal shall support the all the values in

31 valid range for this field.

In een bijdrage van Dr. F. Shad getiteld ‘Optimal Antipodal Signaling’ ten behoeve van een werkgroepbijeenkomst op 9 juli 2001 voor de 3GPP2-standaard staat onder meer het volgende (hierna ook ‘ Shad ’).

Op pag. 1:

Op pag. 2:

Op pag. 3:

Op pag. 5:

Philips heeft ten behoeve van de onderhavige procedure een tweetal hulpverzoeken geformuleerd waarop zij in conventie en reconventie een beroep doet. In het eerste hulpverzoek is aan het slot van conclusie 1 en van conclusies 10 en 15 (in het hulpverzoek omgenummerd naar conclusie 9 respectievelijk 13 omdat verleende conclusies 2 en 14 wegvallen) van EP 525 het volgende kenmerk toegevoegd:

“wherein the available signal types are signals indicating positive and negative acknowledgements, and

wherein the indication specifies the power level relative to the pilot bits on the uplink dedicated control channel.”

Voorts is in conclusie 11 (in het hulpverzoek omgenummerd naar 10) verwezen naar (nieuwe) conclusie 9 en is de zinsnede “the signal types include signals indicating positive and negative acknowledgements and in that” geschrapt.

Het tweede hulpverzoek ziet op de (verdere) toevoeging van “UMTS” aan het “radio communication system” in de aanhef van conclusies 1, 10 en 15 (resp. 1, 9 en 13).