SECOND LIEN COLLATERAL AGENCY AGREEMENT

Exhibit 10.4

EXECUTION VERSION

SECOND LIEN COLLATERAL AGENCY AGREEMENT

This SECOND LIEN COLLATERAL AGENCY AGREEMENT (this Agreement ) dated as of October 9, 2008 is entered into by and among The Bank of New York Mellon, as collateral agent ( Collateral Agent ), and the undersigned Purchasers (together with their successors and assigns and any subsequent holder of Notes under the Purchase Agreement referred to below, the Holders ).

R E C I T A L S

A.        The Holders are the purchasers and holders of Notes under the Second Lien Subordinated Note Purchase Agreement dated as of the date hereof (as the same may be amended, restated, supplemented or otherwise modified from time to time, the Purchase Agreement ) by and among NextWave Wireless LLC, a Delaware limited liability company (the Company ), NextWave Wireless Inc., a Delaware corporation ( Parent ), the other Guarantors from time to time party thereto (the Subsidiary Guarantors and, together with Parent, the Guarantors ), the Purchasers named therein and the Collateral Agent.

B.        The Subsidiary Guarantors and the Collateral Agent, in its capacity as collateral agent and representative for the Holders, have entered into that certain Second Lien Guaranty dated as of the date hereof (as the same may be amended, restated, supplemented or otherwise modified from time to time, the Subsidiary Guaranty ) pursuant to which the Subsidiary Guarantors have guaranteed the payment and performance of the Notes and the obligations of the Company under the Purchase Agreement and other Note Documents (the Obligations ), and Parent and the Collateral Agent, in its capacity as collateral agent and representative for the Holders, have entered into that certain Second Lien Parent Guaranty dated as of the date hereof (as the same may be amended, restated, supplemented or otherwise modified from time to time, the Parent Guaranty ) pursuant to which Parent has guaranteed the Obligations.

C.        The Company, the Guarantors and the Collateral Agent, in its capacity as collateral agent and representative for the Holders, have entered into that certain Second Lien Pledge and Security Agreement dated as of the date hereof (as the same may be amended, restated, supplemented or otherwise modified from time to time, the Security Agreement ), pursuant to which the Company and Guarantors have granted and assigned to the Collateral Agent all of the Companys and the Guarantors right, title and interest in and to the Collateral.

D.        Pursuant to the terms and conditions of the Collateral Documents, the Company and the Guarantors have provided collateral security for all of the Obligations.

E.        Pursuant to the terms and conditions of the Collateral Documents, among other things, the Company and the Guarantors have granted to the Collateral Agent for the benefit of Holders, a security interest in, and a lien on the Collateral.

F.        The Company, the Guarantors, the First Lien Collateral Agent, the Collateral Agent and the Third Lien Collateral Agent have entered into that certain Intercreditor Agreement dated as of the date hereof (as the same may be amended, restated, supplemented or otherwise modified from time to time, the Intercreditor Agreement ).

G.        The Collateral Agent and the Holders wish to enter into this Agreement to, among other things, set forth their understandings and agreements regarding the Holders and the Collateral Agents respective rights, obligations and priorities with respect to the Collateral and all proceeds thereof.

NOW, THEREFORE , for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged and the mutual covenants and promises set forth herein, each of the parties to this Agreement agrees as follows:

1.01       Definitions . Initially capitalized terms used in this Agreement without definition in Exhibit A or otherwise defined herein are defined in the Purchase Agreement.

1.02       Headings . Headings in this Agreement are for convenience of reference only and are not part of the substance hereof or thereof.

1.03       Plural Terms . All terms defined in this Agreement in the singular form shall have comparable meanings when used in the plural form and vice versa.

1.04       Time . All references in this Agreement to a time of day means New York City time, unless otherwise indicated.

1.05       Construction . This Agreement is the result of negotiations among, and has been reviewed by, the Holders, the Collateral Agent and their respective counsel. Accordingly, this Agreement shall be deemed to be the product of all parties hereto and no ambiguity shall be construed in favor of or against any Holder or the Collateral Agent.

1.06       Conflicts . In the event of a conflict between the terms of this Agreement and the terms of any of the other Note Documents with respect to the matters related to the Collateral contained herein, as among the Collateral Agent and the Holders the terms of this Agreement shall control.

1.07       Other Interpretive Provisions . References in this Agreement to Recitals, Sections, Exhibits and Schedules are to recitals, sections, exhibits and schedules herein and hereto unless otherwise indicated. References in this Agreement to any document, instrument or agreement shall (a) include all exhibits, schedules and other attachments thereto, (b) include all documents, instruments or agreements issued or executed in replacement thereof, and (c) mean such document, instrument or agreement, or replacement or predecessor thereto, as amended, modified and supplemented from time to time and in effect at any given time. The words hereof, herein and hereunder and words of similar import when used in this Agreement shall refer to this Agreement as a

whole and not to any particular provision of this Agreement. The words include and including and words of similar import when used in this Agreement shall not be construed to be limiting or exclusive.

2.01       Priority of Liens . The Collateral Agent and the Holders hereby agree that the security interests and liens granted to the Collateral Agent under the Collateral Documents and any claims of the Collateral Agent and/or Holders under guaranties executed by Guarantors shall be treated, as among the Holders, as having equal priority and shall, except to the extent otherwise provided in Section 3.02, at all times be shared by the Holders as provided herein regardless of any claim or defense (including any claims under the fraudulent transfer, preference or similar avoidance provisions of applicable bankruptcy, insolvency or other applicable Governmental Rules affecting the rights of creditors generally) to which the Collateral Agent or any Holders may be entitled or subject.

2.02       Custody of Collateral . From and after the occurrence and during the continuation of an Event of Default, if any Holder acquires custody, control or possession of any Collateral other than any proceeds thereof distributed to such Holder pursuant to the terms of any Note Document, then such Holder shall promptly cause such Collateral to be delivered to, or put in the custody, possession or control of, the Collateral Agent for disposition or distribution in accordance with the provisions of this Agreement and the Intercreditor Agreement. From and after the occurrence and during the continuation of an Event of Default and until such time as the provisions of the immediately preceding sentence have been complied with, such Holder shall be deemed to hold such Collateral in trust for the parties entitled thereto under this Agreement.

2.03       Additional Collateral or Guaranties . None of the Holders shall accept a security interest in, or a Lien on, any collateral for the Obligations other than such Holders beneficial interest in the security interest in, and Lien on, the Collateral granted to the Collateral Agent under the Collateral Documents; provided , however , that nothing contained in the foregoing shall be construed as prohibiting the opening and maintenance of deposit accounts for the account of the Company or Guarantors in the ordinary course of business. No Holder shall accept any guaranty of its Obligations from any Person unless such Person has previously or simultaneously guaranteed the Obligations held by each of the other Holders.

2.04       Enforcement of Remedies . Upon the occurrence and during the continuation of any Event of Default, the Collateral Agent shall, subject to the other provisions of this Agreement, take such action with respect to such Event of Default as shall be directed by the Required Holders (a Direction Notice ); provided , however , that, in the absence of a Direction Notice, the Collateral Agent may (but shall not be obligated to) take such action, or refrain from taking such action, with respect to such Event of Default as it shall deem advisable in the best interests of the Holders (other than the exercise of foreclosure remedies). Upon receipt by the Collateral Agent of a Direction Notice, the Collateral Agent shall seek to enforce the Collateral Documents and to realize upon the

Collateral in accordance with such Direction Notice; provided , however , that the Collateral Agent shall not follow any Direction Notice if the Collateral Agent reasonably determines on the basis of an opinion of counsel that such Direction Notice is in conflict with any provisions of any applicable Governmental Rule, this Agreement or any of the relevant Collateral Documents, and the Collateral Agent shall not, under any circumstances, be liable to any Holder, the Company or any other Person for following a Direction Notice.

2.05       Remedies of the Holders . Unless otherwise consented to in writing by the Required Holders, no Holder, individually or together with any other Holder, shall have the right to, nor shall it, exercise or enforce any of the rights, powers or remedies which the Collateral Agent is authorized to exercise or enforce under this Agreement or any of the Collateral Documents.

(a)       Collateral Agent shall provide to any Holder, when and if requested by such Holder, a copy of the Register delivered to Collateral Agent by the Company in accordance with Section 1.7(a) of the Purchase Agreement.

(b)         If the Collateral Agent proceeds to foreclose upon, collect, sell or otherwise dispose of or take any other action with respect to any or all of the Collateral or to enforce any provisions of the Collateral Documents or takes any other action pursuant to this Agreement or any provision of the Collateral Documents or requests directions from the Holders as provided herein, upon the request of the Collateral Agent, each of the Holders (or any agent of or representative for such Holder) shall promptly deliver a written notice to the Collateral Agent and each of the other Holders setting forth (a) the aggregate amount of principal, interest, fees, and other Obligations owing to such Holder under the applicable Note Documents as of the date specified by the Collateral Agent in such request and (b) such other information as the Collateral Agent may reasonably request.

(a)       Upon receipt of a Direction Notice, the Collateral Agent shall establish a collateral proceeds account subject to the Lien created by the Collateral Documents in the name of the Collateral Agent into which the Proceeds (as defined below) shall be deposited and from which only the Collateral Agent may effect withdrawals (the Collateral Proceeds Account ). Such amounts shall be held by the Collateral Agent in the Collateral Proceeds Account and shall be distributed from time to time by the Collateral Agent in accordance with Section 3.02.

(b)       Following the occurrence and during the continuation of an Event of Default, the following proceeds, payments and amounts (collectively, the Proceeds ) shall be deposited and held by the Collateral Agent in the Collateral Proceeds Account and shall be distributed from time to time by the Collateral Agent to the Holders in accordance with Section 3.02:

(i)        any proceeds of any collection, recovery, receipt, appropriation, realization or sale of any or all of the Collateral through the enforcement of the Collateral Documents received by the Collateral Agent or any Holder; and

(ii)       any amounts held in the Collateral Proceeds Account at the time an Event of Default occurs.

Each Holder agrees to deliver any Proceeds to the Collateral Agent within three (3) Business Days after receipt of such Proceeds, or if later (in the case of clause (ii)), within three (3) Business Days of being advised of the occurrence of an Event of Default. Until such time as the provisions of the immediately preceding sentence have been complied with, such Holder shall be deemed to hold such Proceeds in trust for the parties entitled thereto under this Agreement.

3.02       Distribution of Proceeds . The Collateral Agent, at the request of the Holders, shall distribute the Proceeds which are held in the Collateral Proceeds Account in accordance with Section 12 of the Security Agreement, it being understood, however, that the Collateral Agent may deduct from any distribution the amount of all Collateral Agents reimbursable fees and expenses that have not been paid by the Company or the Holders pursuant to Section 4.03 or otherwise. The Collateral Agent shall make such distributions as promptly as reasonably practicable after the deposit of any Proceeds into the Collateral Proceeds Account and in any event within five (5) Business Days of receipt thereof.

3.03       Distributions Recovered . Notwithstanding anything to the contrary contained in this Agreement, in each case in which any proceeds (or the value thereof) or payments are recovered as a preferential or otherwise voidable payment (whether by a trustee in bankruptcy or otherwise) from the party which distributed those proceeds to another party or parties under this Agreement (the Distributor ), each party to whom any of those proceeds were ultimately distributed (a Distributee ) shall, upon the Distributors notice of the recovery to the Distributee, return to the Distributor an amount equal to the Distributees ratable share of the amount recovered, together with a ratable share of interest thereon to the extent the Distributor is required to pay interest thereon computed on the amount to be returned from the date of the recovery. For purposes of this Agreement, proceeds means any payment (whether made voluntarily or involuntary) from any source, including any offset of any deposit or other indebtedness, any security (including any guaranty or any collateral) or otherwise.

4.01       Appointment, Powers and Immunities . Each Holder has appointed and authorized the Collateral Agent to act as its agent hereunder and under the Note Documents with such powers as are expressly delegated to the Collateral Agent by the terms of the Note Documents, together with such other powers as are reasonably incidental thereto. The Collateral Agent shall not have any duties or responsibilities except those expressly set forth in the Note Documents. Notwithstanding anything to the contrary contained herein, the Collateral Agent shall not be required to take any action which is contrary to any Note Document or any applicable Governmental Rule. The Collateral Agent may employ agents and attorneys-in-fact

and shall not be responsible to the Holders or any Holder for the negligence or misconduct of any such agents or attorneys-in-fact selected by it with reasonable care.

Notwithstanding anything in any Note Document to the contrary, the Collateral Agents duties under all such Note Documents are administrative only and it shall not be required under any circumstances to exercise discretion in the performance of its duties under any Note Document, but shall be required to act or to refrain from acting upon instructions of the Required Holders and shall in all cases be fully protected by the Holders in acting, or in refraining from acting, hereunder or under any Note Document in accordance with the instructions of the Required Holders, and such instructions of the Required Holders and any action taken or failure to act pursuant thereto shall be binding on all of the Holders. As to any other matters not expressly provided for by any Note Document, the Collateral Agent shall n