(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2007/0097901 A1
`
`Tirkkonen et al.
`(43) Pub. Date:
`May 3, 2007
`
`US 20070097901Al
`
`(54) APPARATUS, METHOD AND COMPUTER
`PROGRAM PRODUCT PROVIDING
`COMMON CHANNEL ARRANGEMENTS
`FOR SOFT FREQUENCY REUSE
`
`Related US. Application Data
`
`(60) Provisional application No. 60/731,552, filed on Oct.
`28: 2005-
`
`Publication Classification
`
`(75)
`
`Inventors: Olav Tirkkonen, Helsinki (Fl); Preben
`.
`_
`Mogensen, Gistrup (DK); Mika P.
`Rlnne, ESPOO (F1)
`
`(51)
`
`Int. Cl.
`H043
`(52) US. Cl.
`
`(2006.01)
`7/185
`............................................ 370/318; 455/522
`
`Correspondence Address:
`HARRINGTON & SMITH, PC
`4 RESEARCH DRIVE
`3
`SHELTON CT 06484-6212 (US)
`
`(73) Assignee: Nokia Corporation
`
`(21) Appl. No.:
`
`11/588,519
`
`(22)
`
`Filed:
`
`Oct. 27, 2006
`
`(57)
`
`ABSTRACT
`.
`.
`.
`.
`.
`A deVice includes Circuitry adapted to place at least a portion
`of at least one common channel on a fraction of an available
`bandwidth of a cell in a cellular communication system that
`uses soft reuse such that different orthogonal transmission
`resources are transmitted with different transmission powers
`and power usage is planned on a cell-by-cell basis; and a
`.
`.
`.
`transmitter to transmit the common channel into the cell for
`
`reception by a plurality of receivers. Also disclosed is a
`method and a computer program product operable with the
`device.
`
` l-ZH Hm
`
`
`
`
`APPLE 1023
`
`APPLE 1023
`
`

`

`Patent Application Publication May 3, 2007 Sheet 1 0f 5
`
`US 2007/0097901 A1
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`.fixxoaumzH@MDGE
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`

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`Patent Application Publication May 3, 2007 Sheet 2 of 5
`
`US 2007/0097901 A1
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`

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`Patent Application Publication May 3, 2007 Sheet 3 of 5
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`US 2007/0097901 A1
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`(a) DRX optimized
`
`
`
`
`
`EIIIIIIIIIIIIIIIIII
`Ellllfllfllllllllfll
`
`§lllllllllllllllll=
`Ellllllllllllflllfll—
`
`Elwin"lllllllllllllllllllllll—
`
`(c) Allowing larger CCH
`
`
`
`
`
`
`
`.
`.
`LEGeuD
`:l Downlink Shared channeliDSCl—l) (and possible dediCated pilots)
`
`WW Control channlel (CCH), primary resources
`
`
`
`: mm Secondary resources for'bontrol channels (used for CCH if required, else for DSCH)
`
`I 3 Common 'pilo't subcér’n‘ers with other subcarriers used for D_SCH
`
`
`
`Common pilot subcarriers with other Subcarriers used for CCH
`
`
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`
`
`
`
`
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`
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`
`
`Common pilot subcarriers with other subcarriers used for CCH if I
`'
`' required, else for DSCH
`'
`
`Fina-0R6 3
`
`

`

`Patent Application Publication May 3, 2007 Sheet 4 of 5
`
`US 2007/0097901 A1
`
`
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`
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`//
`
`(a) DRX optimized
`
`7///}C’////lllllll
`
`=|||||||
`
`‘ lllll—
`
`
`fillll—
`
`
`
`(c) Allowing larger CCH
`
`Lasso!)
`-
`'
`“
`l:|. Downlink Shared channel (DSCH) (and possible dedicated pilots)
`- WWW Control Channlel (CCH), primary resources
`
`'
`
`BMW Secondary resources for Control channels (used for CCH if required, else for DSCH) ‘
`
`
`
`
`
`g Common pilot subcarriers with other subcarriers used‘for' DSCH
`
`Common pilot subcarriers with other subcarriers used forCCH
`
`Common pilot subcarriers with other subbaniers used for CCH if
`required, else for DSCH
`
`Common pilot subcarriers with System—info transmitted on other subcarriers
`%/
`. Reufie ' ‘4
`
`,4
`
`'
`
`

`

`Patent Application Publication May 3, 2007 Sheet 5 of 5
`
`US 2007/0097901 A1
`
`
`(5A) PLACING AT LEAST A PORTION OF AT
`LEAST ONE COMMON CHANNEL ON A
`
`FRACTION OF AN AVAILABLE BANDWIDTH
`
`OF A CELL IN A CELLULAR
`COMMUNICATION SYSTEM THAT USES SOFT
`
`REUSE SUCH THAT DIFFERENT
`
`ORTHOGONAL TRANSMISSION RESOURCES
`
`ARE TRANSMITTED WITH DIFFERENT
`
`TRANSMISSION POWERS AND POWER USAGE
`IS PLANNED ON A CELL-BY—CELL BASIS
`
`
`
`
`
`
`
`
`
`
`
`(5B) TRANSMITTING THE COMMON
`CHANNEL INTO THE CELL FOR
`
`
`RECEPTION BY A PLURALITY OF
`
`
`RECEIVERS
`
`
`FIGURE 5
`
`
`
`(6A) RECEIVING AT LEAST A PORTION OF
`
`AT LEAST ONE CONIMON CHANNEL FROM
`
`
`DIFFERENT ORTHOGONAL TRANSMISSION
`
`
`RESOURCES ON A FRACTION OF AN
`
`AVAILABLE BANDWIDTH OF AT LEAST ONE
`OF HIGHER TRANSMISSION POWER OR A
`LOWER TRANSMISSION POWER OF SOFT
`REUSE
`
`
`
`
`
`
`
`
`(6B) USING INFORMATION IN
`THE RECEIVED COMMON
`
`CHANNEL
`
`
`
`
`
`FIGURE 6
`
`

`

`US 2007/0097901 A1
`
`May 3, 2007
`
`APPARATUS, METHOD AND COMPUTER
`PROGRAM PRODUCT PROVIDING COMMON
`CHANNEL ARRANGEMENTS FOR SOFT
`FREQUENCY REUSE
`
`CLAIM OF PRIORITY FROM COPENDING
`PROVISIONAL PATENT APPLICATION
`
`[0001] This patent application claims priority under 35
`U.S.C. §ll9(e) from Provisional Patent Application No.
`60/731,552, filed Oct. 28, 2005, the disclosure of which is
`incorporated by reference herein in its entirety.
`
`TECHNICAL FIELD
`
`[0002] The exemplary and non-limiting embodiments of
`this invention relate generally to wireless cellular commu-
`nications systems and devices and, more specifically, relate
`to those wireless cellular communications systems that
`employ soft frequency reuse with channels transmitted to a
`receiver.
`
`BACKGROUND
`
`[0003] The following abbreviations are herewith defined.
`
`[0004]
`
`3GPP third generation partnership project
`
`[0005] UTRAN universal terrestrial radio access network
`
`[0006] E-UTRAN evolved UTRAN
`
`[0007] CDM code division multiplex
`
`[0008] CCH common channel
`
`[0009] DL downlink (Node B to UE)
`
`[0010]
`
`[0011]
`
`[0012]
`
`[0013]
`
`UL uplink (UE to Node B)
`DSCH downlink shared channel
`
`DRX discontinuous reception
`DTX discontinuous transmission
`
`[0014]
`
`DSP digital signal processor
`
`[0015]
`
`FDM frequency division multiplex
`
`[0016]
`
`[0017]
`
`[0018]
`
`[0019]
`
`FDMA frequency divisional multiple access
`Node B base station
`
`OFDM orthogonal frequency division multiplex
`SR sub-band soft reuse sub-band
`
`[0020]
`
`TDM time division multiplex
`
`[0021]
`
`UE user equipment
`
`[0022]
`
`WCDMA wideband code division multiple access
`
`[0023]
`
`WCDMA LTE WCDMA long term evolution
`
`interference is a serious problem that
`Inter-cell
`[0024]
`needs to be addressed during the design of a multi-cellular
`communication system. Some conventional systems reduce
`the amount of interference of geographically adjacent cells
`by allocating their carrier frequencies to different center
`frequencies, separated by the bandwidth of the carrier. Thus,
`there is a reuse factor, which determines tiers of geographi-
`cal cells such that base stations transmitting on the same
`center frequency are much further away than the geographi-
`cally closest neighbors. This approach is known to compli-
`
`cate network planning, since when introducing a new base
`station the operator may need to update the frequency plan
`of all the base stations in that area.
`
`Some modern systems, such as WCDMA, are
`[0025]
`designed so that frequency reuse planning is not needed at
`all, i.e., full coverage network can be deployed by applying
`the same frequency in all the cells within a certain geo-
`graphical area. This is also preferred as the system band-
`width can be large, e.g., 5 MHZ for WCDMA. Thus, it would
`not be efficient to deploy such a wideband system with
`frequency reuse. WCDMA, as any modem signal structure,
`is designed so that a frequency reuse 1 deployment
`is
`possible, practical and efficient.
`
`[0026] This same requirement has been set for E-UTRAN.
`The system bandwidth of E-UTRAN is scalable from values
`ranging from 1.25 MHZ up to 20 MHZ, and possibly even
`higher (e.g., up to 100 MHZ).
`
`[0027] E-UTRAN will be designed so that DL transmis-
`sion is a multi-carrier signal, where a mathematical trans-
`form is applied to form sub-carriers, each of which carry
`modulated symbols. Such a block of sub-carrier symbols is
`referred to as an OFDM symbol, if the transforms applied
`are DFT or FFT transforms. Other types of multi-carrier
`compositions exist by other mathematical transforms, such
`as sine or cosine transforms, lapped transforms, bi-orthogo-
`nal transforms,
`isotropic transforms, etc. In the UL, the
`E-UTRAN may be a similar multi-carrier signal as well, but
`is presently defined as a single carrier, FDMA (SC-FDMA)
`characterized by a frequency division multiplex of users. In
`any of the afore-mentioned techniques, the frequency reuse
`1 technique is feasible.
`
`[0028] One potential solution to the inter-cell interference
`problem employs a so-called soft reuse method (in time/
`frequency). In a soft reuse method, different orthogonal
`transmission resources are given different transmission pow-
`ers, and the power usage is planned in the cellular system on
`a cell-by-cell basis. While time domain soft reuse may be
`applied to any multiplexing technology, frequency domain
`soft reuse requires the presence of a multi-carrier system in
`order to be applicable.
`
`[0029] While soft reuse has been considered in the time
`domain and in the frequency domain, a frequency domain
`arrangement is more advantageous in an asynchronous com-
`munication system. It has been stressed in the requirements
`for WCDMA LTE that the E-UTRAN should be operable in
`an asynchronous fashion (see 3GPP TR 25.913, “3rd Gen-
`eration Partnership Project; Technical Specification Group
`Radio Access Network; Requirements for Evolved UTRA
`(E-UTRA) and Evolved UTRAN (E-UTRAN); (Release
`7)”. As such, a frequency domain soft reuse implementation
`is a strong candidate for a LTE system architecture. Such has
`been suggested in 3GPP by Huawei (“Soft frequency reuse
`scheme for UTRAN LTE”, Rl-050404, Athens meeting,
`May 2005). Reference may also be made to Alcatel, “Inter-
`ference coordination in new OFDM DL air interface”,
`Rl-050407, Athens meeting, May 2005 (attached hereto as
`Exhibit B), and to Ericsson, “Inter-cell interference handling
`for E-UTRA”, Rl-050764, August 2005. Note also the
`“Flarion FLEXband” concept (Signals Ahead, Vol 2, no 3,
`February 2005).
`
`[0030] Further, the concept of soft reuse is well described
`in the commonly assigned US. Pat. No. 6,259,685 B1,
`
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